Introduction

Pornography use can have positive effects on one’s overall psychological functioning, such as helping one explore one’s sexuality and normalizing sexual desires (McKeown et al. 2018). Although the consumption of pornography is not inherently problematic, a segment of the population self-identifies as being addicted to pornography, as they perceive their use of pornography to affect their overall psychological well-being and their social and vocational functioning (Sniewski et al. 2018; Twohig and Crosby 2010). The use of the term ‘perceived’ is intentional, as pornography use is considered problematic based on the subjective interpretation of one’s behavior. Hence, a person may perceive themselves to have a problem with pornography addiction if they watch porn 3 or 30 times a day, depending on one’s own evaluation of their behavior. Self-perceived problematic pornography use (SPPPU) is mostly related to people who feel unable to regulate their pornography use (Sniewski et al. 2018). The criteria used to evaluate one’s behavior regarding their pornography use is varied, although self-perceived pornography addiction has been significantly associated to religiosity, moral disapproval, identifying as male, and average pornography use per day (Grubbs et al. 2019; Grubbs et al. 2015). Given the subjective nature in defining pornography addiction, efforts in integrating levels of analysis in research are complicated (Sniewski et al. 2018). Hence, we propose a model of self-perceived problematic pornography use, in which we highlight how different levels of analysis (i.e., from biological to societal) can provide insight into this construct, to help guide mental health professionals to better consume research and provide better services to those who perceive themselves to have a problem with pornography use. By critically consuming pornography research, mental health practitioners may explore both ‘pro’ and ‘anti’ pornography discourse with clients who struggle with the extent and content of their consumption of pornography, leading to a decrease on their overall distress (Barker 2014). Hence, our model also fosters a critical analysis of pornography research and consumption, opposed to a polarization between pro- and anti-pornography stances (Smith and Attwood 2014).

Self-Perceived Problematic Pornography Use

Self-perceived problematic pornography use (SPPPU) can be a public health concern due to its adverse effects in multiple levels, ranging from individual to societal impact (Love et al. 2015; Perry 2017; Kingston et al. 2009). The self-perceived overuse of pornography (i.e., SPPPU) has a significant and negative effect on well-being (Grubbs et al. 2013), as internet pornography is pervasive and easily accessible to all. The United States has the largest market of pornography production, distribution, and consumption (Perrin et al. 2008). The global pornography industry net worth is about 97.1 billion dollars, with 13.3 billion in the United States alone, which exceeds the combined revenues of professional football, baseball, and basketball franchises (Perrin et al. 2008). According to PornHub (2018), one of the industry’s largest providers, in 2017 alone they had 28.5 billion visitors, an average of 81 million visitors per day, and an average of 800 searches per second. Moreover, PornHub (2018) reported over 4 million videos were uploaded in 2017, with enough hours to spend 68 years continuously watching pornography. There was an average of 118 GB of data streamed per second during 2017, which according to the report, would be enough data to fill the memory of every iPhone currently in use around the world.

Access to pornography has significantly changed in the past decade, as high-speed internet services allowed for immediate access to a variety of pornographic content (Ashton et al. 2019). The immediacy of internet pornography has been found to have adverse effects on people’s overall functioning and well-being, such as lower sex drive, erectile dysfunction, higher endorsement of rape myths, and violence against women (Kingston et al. 2009; Park et al. 2016). Literature on SPPPU use has increased in the past decade, mainly focusing on the establishment of pornography overuse as a problem despite its exclusion from the DSM-5 (Love et al. 2015; Hajela and Love 2017) and identification of specific mechanisms involved in self-perceived pornography overuse (Cotigă and Dumitrache 2015). Previous studies on this topic were fundamental in the establishment of evidence for ‘pornography addiction’. However, this topic has been studied through different lenses, and has not been integrated in the literature. Different researchers have addressed a small piece of the puzzle, but there has not been an integration among the different units of analysis and intersectionality of this issue, which may hinder studies on prevention and treatment effectiveness for problematic pornography use.

This review will fill this gap in the literature by proposing a unifying paradigm to assess pornography overuse, in which different levels of analysis are integrated using an ecological model and a Research Domain Criteria (RDoC) perspective, from molecules to sociopolitical impact. Using an ecological model to organize risk factors and impact of SPPPU allows for understanding how this complex and dynamic system of factors interacts within and across levels (i.e., micro, meso, exo, and macrosystems) to increase risk or protection. These risk factors, “from the individual to the global, play out within an immediate and historical milieu of oppressions on the basis of gender and sexuality, race and ethnicity, social class, and other identities” (APA 2014, p. 22). Due to the complexity and interaction of these systems, preventive and remedial efforts that target only single risks have limited utility (IOM 2013). Therefore, a comprehensive understanding of different levels of risk factors and impact of self-perceived overuse of pornography is important to conduct relevant research and provide effective treatment and prevention strategies.

Moreover, the RDoC perspective will be used as a magnifying glass to look at the microsystem of pornography overuse, reviewing research produced on the molecular, circuitry, physiological, and behavioral levels of analysis. The RDoC was developed by the National Institute of Mental Health (NIMH) in order to introduce a dimensional model of understanding mental illness, enhance the study of brain-behavior relationships, and foster precision medicine in psychiatry (Kozak and Cuthbert 2016; Clark et al. 2017). The RDoC framework emphasizes and encourages the integration of behavioral and neuroscience research by using different units of analysis (e.g., molecular, circuits, physiology, behavioral, self-report). Although environmental and developmental factors are recognized as essential in every level of analysis in the RDoC model, these factors are commonly neglected and not made explicit in research. Indeed, there has been a call for more integration of environmental and developmental factors in research using the RDoC model (Lilienfeld 2014; Cuthbert 2014; Shankman and Gorka 2015). In that effort, it is valuable to examine macro-level units of analysis that go beyond the individual, given that people are nested in an ecological environment that includes families, communities, institutions, and historical epoch.

The goal of this review was to integrate different areas of literature, to create a thorough and comprehensive model of self-perceived problematic pornography use. The ultimate objective was to combine both RDoC and ecological models, to better guide and integrate research in different levels of analysis. The goal of integrating the literature on problematic pornography use (i.e., pornography addiction) is to encourage different ways of conceptualizing and developing research in this area from an integrative perspective and stimulate treatment interventions that include social prevention. Additionally, an integrated model will likely aid prevention and public policy making, with the intent to increase individual well-being in society, individually, and developmentally. This study is an integration of the available literature through an ecological and RDoC lenses, and will be organized as follows: (a) a definition of pornography and self-perceived pornography use will be provided, (b) the different units of analysis will be addressed through the RDoC lens, including molecules, circuits, and behavior, and how they are interrelated, (c) the different systems of the ecological model will be presented as they pertain to pornography use, and (d) a critique of the implications for future research and practice based on the proposed model will be discussed.

Definitions: Current Issues and Models

Pornography can be defined as visual stimuli (i.e., pictures or videos) that have been produced professionally or nonprofessionally with the intent of sexually arousing the viewer (Attorney General Commission on Pornography 1986; Sniewski et al. 2018). In a recent review of published manuscripts on pornography, Ashton et al. (2019) proposed a new definition of pornography taking in consideration the different parameters set by the digital age, considering both participants and consumers. The authors noted that pornography can be defined as “material deemed sexual, given the context, that has the primary intention of sexually arousing the consumer, and is produced and distributed with the consent of all persons involved” (Ashton et al. 2019, p. 163). Pornography is, therefore, separate from any material that involves sexual exploitation of children and non-consenting adults. Although it is important to make the definition of pornography clear and consistent in the literature, it is also important to note that consumers of erotic material are not able to make a distinction between pornography and sexual exploitation, further complicating the investigation of the societal impact of pornography.

‘Pornography addiction’, on the other hand, is a controversial term in the literature due to the non-recognition of behavioral addictions by the DSM, and a lack of a formalized conceptualization and parsimonious criteria across research (Love et al. 2015; Sniewski et al. 2018; Ley et al. 2014). Nevertheless, the term pornography addiction has been widely used, mostly due to the vast body of research in neuropsychology that has consistently shown the same mechanisms and circuitry involved in substance addiction are also involved in pornography addiction (Hajela and Love 2017; Love et al. 2015). There have been many critiques regarding the criteria for conceptualizing addiction in the DSM-5, as well as the exclusion of behavioral addictions (Hajela and Love 2017). Many authors have called for an expansion of the addiction diagnosis recognized by the American Psychiatric Association (APA), in keeping with other countries and research in the area, in order to provide more rigorous and consistent treatment for populations affected by behavioral addictions (Hajela and Love 2017; Love et al. 2015).

Some authors contend however, that the term ‘pornography addiction’ is inaccurate, stigmatizing, and pathologizing, given moral and historical values that regard sexual activity as a taboo topic (Voss 2015). In this review, we use the term self-perceived problematic pornography use (SPPPU), defined as self-identified pornography addiction and feelings of inability to regulate pornography use (Sniewski et al. 2018). This definition is important as it highlights the user’s subjective perception regarding their pornography use and its consequences, which is commonly the basis for research and treatment. Problematic pornography consumption, or ‘pornography addiction’, will be conceptualized as “any use of pornography that leads to and/or produces significant negative interpersonal, vocational, or personal consequences for the user” (Sniewski et al. 2018, p. 217).

Research Domain Criteria (RDoC) and SPPPU

The RDoC will be used in this review of literature to organize the different units of analysis involved in SPPPU. An integrated understanding of the different individual-level factors that influence the development and maintenance of SPPU can increase understanding and clinical conceptualization of this phenomena. Therefore, a summary of studies conducted in this area will be organized according to different units of analysis according to the RDoC framework, namely molecules, circuits, and behavior (Fig. 1), which integrate into a generalized understanding of SPPPU.

Fig. 1
figure 1

Integration of different units of analysis of self-perceived problematic pornography use using the RDoC perspective

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Molecules

Arousal can be explained in neurobiological terms, in which regions of the limbic system (e.g., hypothalamus, amygdala, hippocampus) are linked with neurons that create synapses that travel down the spinal cord and through other neurons in the genitals. Arousal can also be explained by hormones, such as oxytocin, vasopressin, and dopamine, which can act as neuromodulators. Dopamine released during sexual excitement activates the brain’s reward system (Cotigă and Dumitrache 2015). Although research in the molecular mechanisms involved in SPPPU is limited, the molecules found to be most commonly associated with SPPPU are dopamine, ΔFosB, and glutamate.

Researchers have found that dopamine seems to be the key in understanding SPPPU, as it is related to the reward system, arousal, and brain plasticity (Love et al. 2015; Cotigă and Dumitrache 2015; Hilton 2013; Park et al. 2016). Myelination is an adaptive process of weakening or removal of old connections as well as strengthening or creation of new ones, and it is essential in brain plasticity. According to the hebbian learning rule (i.e., “neurons that fire together, wire together”), the brain develops new sexual maps after long-term exposure to pornography material, which is reinforced by the reward circuit through dopamine release after viewing pornography and reaching orgasm (Cotigă and Dumitrache 2015; Park et al. 2016). However, overuse of pornography can also dull the reward system, due to the brain’s protective mechanism from excess dopamine, which decreases the sensitivity to the neurotransmitter. This leads to a decrease in satisfaction and increased need for more sexual stimuli in order to obtain an erection (Cotigă and Dumitrache 2015).

Further, increasing evidence suggests the transcription factor ΔFosB represents one of the mechanisms by which addiction can produce relatively stable changes in the brain (Nestler et al. 2001; Hilton 2013). ΔFosB accumulates within a subset of neurons of the nucleus accumbens and dorsal striatum after repeated administration of different kinds of drugs of abuse, as well as after performing compulsive behaviors. After accumulation, ΔFosB remains in neurons for relatively long periods of time due to its enduring stability. According to a recent review, ΔFosB functions as a type of sustained ‘‘molecular switch’’ that slowly converts acute reward responses, such as those present in pornography use, into relatively stable adaptations. These adaptations seem to underlie addiction, because they contribute to long-term neural and behavioral plasticity (Nestler et al. 2001). The effect of ΔFosB on dendritic plasticity seems to be mediated by the D1 dopamine receptor in the nucleus accumbens, and dopamine has been shown as central in assigning salience to sexual cues (Hilton 2013).

Circuits

The most prominent circuit involved in SPPPU is the mesolimbic dopaminergic pathway (i.e., reward circuit; Brand et al. 2016; Love et al. 2015; Park et al. 2016; Hilton 2013). Several key brain regions are involved in male sexual response. The hypothalamic nuclei provides the integration between brain and peripheral input and facilitates erections by receiving input from the mesolimbic dopamine pathway, which comprises the ventral tegmental area (VTA) and the nucleus accumbens (NAc). The VTA-NAc circuit, commonly called the reward system, detects rewarding stimuli, and largely regulates response to natural rewards. Erections depend upon the activation of dopaminergic neurons in the VTA and dopamine receptors in the NAc, facilitated by excitatory glutamate inputs from other limbic structures (e.g., amygdala, hippocampus) and the prefrontal cortex. Dopamine signaling in the reward system and hypothalamus seems to play a central role in sexual arousal, sexual motivation and penile erections (Park et al. 2016).

The Reward System

Chronic internet pornography use can alter the circuits involved in the reward system. Hyper-reactivity to pornography cues by means of glutamate inputs, which can lead to downregulation of the response of reward system to normal sexual rewards (Park et al. 2016). The unique properties of internet pornography, namely the video format, novelty, immediacy, and potential for easy escalation, may condition sexual arousal to these unique aspects of internet pornography that may not translate to real-life partners, leading to decline in arousal (Park et al. 2016). Moreover, executive input from frontal regions has been shown to modulate the mesencephalic dopaminergic reward impetus projecting to the nucleus accumbens–ventral striatal reward region in humans when it relates to sexual behavior (Hilton 2013). Dendritic arborization precedes gyral sculpting that occurs with learning, and reward-based learning is no different. Addiction can be thought of as a powerful way of learning, but with the consequential neuroplasticity being detrimental (Hilton 2013).

The ventral striatum seems to have a central role in processing reward anticipation and gratification linked to subjectively preferred pornographic material. Gola et al. (2017) conducted a double-blind study which examined ventral striatal responses to erotic and monetary stimuli using functional magnetic resonance (fMRI). The researchers found that sensitivity to cues predicting erotic pictures, when compared to cues predicting monetary gains, was significantly related to increased behavioral motivation to view erotic images, which suggests higher ‘wanting’. The researchers also found this pattern of increased cue-related ‘wanting’ in the SPPPU group was dissociated from reward-related ‘liking’, which was found in the control group, resembling findings in the substance addiction literature.

Furthermore, aside from high levels of activation of the VTA in people with SPPPU, the frontostriatal network seems to have a role as well, due to its connection to reward and novelty-seeking behavior. Kühn and Gallinat (2014) conducted a cross-sectional experimental study and found a significant negative association between reported use of pornography per week and gray matter volume in the right caudate. According to the authors, this negative association could reflect change in neural plasticity as a consequence of intense stimulation of the reward system, paired with a lower top-down modulation of prefrontal cortical areas. The observed gray matter cluster in the striatum are implicated in reward delivery and anticipation, as well as coding reward magnitude and salience. This suggests that intense exposure to pornographic stimuli results in downregulation of the natural neural response to sexual stimuli.

Late Positive Potentials

There has been some evidence for differences in LLP (late positive potential) amplitude among people who reported having problematic pornography use. Prause et al. (2015) conducted a study with 122 heterosexual men and women who reported SPPPU. Participants were exposed to unpleasant, neutral, pleasant non-sexual, pleasant sexual, and pleasant explicit-sexual images while their evoked potentials were recorded. Among the group of participants that reported a problematic pornography use, the level of desire for sex with a partner predicted late positive potential (LPP) amplitude. Hence, these participants reported higher sexual desire and had lower LPP in response to sexual images when compared to non-sexual images. Gola (2016) argues that sexual images might play the role of rewards, due to their innate (i.e., biological sexual drive) and learned (i.e., association with orgasm) reward values. Therefore, lower LPP for sexual images in problematic pornography users reflects diminishing in “liking”. Additionally, it is important to note that these findings come from an artificial laboratory setting, as participants were asked not to masturbate in this study, which could result in lower LPP amplitudes due to an effort to downregulate sexual responses.

In a recent study, Kunaharan et al. (2017) investigated whether frequency of pornography use affected non-conscious and conscious emotion processes. The authors suggest a desensitization and physiological downregulation process due to habituation effects in those participants who frequently seek pornographic material. ERPs showed changes in frontal and parietal regions of the brain in relation to “pleasant” and “violent” emotion picture categories, which seemed to be processed similarly in the brain in high frequency porn users. The researchers suggest that this pattern of physiological responses could be a consequence of frequent exposure to pornographic material, which can increase “liking” and approach motivation towards pornography, resulting in an intensified LPP. This LPP seems to be comparable to the LPP generated when viewing violent imagery, due to the possible effects of avoidance motivation. Be it as it may, it seems that there is a difference in LPP amplitude in people with SPPPU. Further research in this area is needed, to better understand how learning, liking, and approach motivation influence problematic pornography use, and its effects on neuroplasticity. Neuroplasticity of brain circuits and processes also appear to be closely connected to behavior and can affect behavioral responses of those with SPPPU.

Behavior

Although scarce, there have been a few studies that address the behavioral risk factors and effects of SPPPU. Overall, reduced executive control over multitasking performance, high approach/avoid tendencies towards pornographic stimuli, and high conditioning effects seem to be related to self-perceived problematic pornography use (Snagowski and Brand 2015; Schiebener et al. 2015; Snagowski et al. 2016). These are also comparable to behavioral effects observed in the substance addiction literature (Love et al. 2015), and have been found to be related to negative consequences in personal and work settings (Schiebener et al. 2015).

In a study with 123 heterosexual males who used internet pornography an average of 3.6 times per week and spent an average of 22 min per visit, participants completed an Approach-Avoidance-Task (AAT) modified with pornographic pictures. The authors found that participants with tendencies toward internet pornography addiction also tended to either approach or avoid pornographic stimuli. Moreover, participants with self-reported high sexual excitation and problematic sexual behavior who showed high approach/avoidance tendencies, reported higher symptoms of pornography addiction. The same approach/avoidance tendencies found in substance addiction seem to play a role in internet pornography addiction, and an interaction with sensitivity toward sexual excitation and problematic sexual behavior could have an accumulated effect on the severity of people’s complaints related to SPPPU (Snagowski and Brand 2015).

These approach/avoidance tendencies are also related to diminished executive control over cognition and behavior. One study found that participants with self-reported tendencies toward problematic pornography use had a less balanced performance in a multitasking paradigm, by either overusing or neglecting to work on pornographic pictures (Schiebener et al. 2015). Another study showed that neutral stimuli can be conditioned to rewarding outcomes of pornographic pictures (i.e., sexual arousal), and that the strength of this learning process is related to internet pornography tendencies. Participants completed a Standard Pavlovian to Instrumental Transfer Task modified with pornographic pictures, and researchers found that the interaction between the conditioning of neutral stimuli and strength of this conditioning might increase risk for developing and maintaining problematic pornography use (Snagowski et al. 2016).

Summary of the RDoC Framework for SPPPU

Self-perceived problematic pornography use seems to be related to multiple units of analysis and different systems in the organism. Based on the findings within the RDoC paradigm described above, it is possible to create a cohesive model in which different units of analysis impact each other (Fig. 1). It appears that elevated levels of dopamine, present in the natural activation of the reward system related to sexual activity and orgasm, interfere with the regulation of the VTA-NAc system in people who report SPPPU. This dysregulation leads to greater activation of the reward system and increased conditioning related to the use of pornography, fostering approach behavior to pornographic material due to the increase in dopamine in the nucleus accumbens. Continued exposure to immediate and easily available pornographic material seems to create an imbalance in the mesolimbic dopaminergic system. This excess dopamine activates GABA output pathways, producing dynorphin as a byproduct, which inhibits dopamine neurons. When dopamine decreases, acetylcholine is released and can generate an aversive state (Hoebel et al. 2007), creating the negative reward system found in the second stage of addiction models. This imbalance is also correlated to the shift from approach to avoidance behavior, seen in people who report problematic pornography use.

These changes in internal and behavioral mechanisms among people with SPPPU are similar to those observed in people with substance addictions, and map into models of addiction (Love et al. 2015). However, these changes occur in an organism that lives within a family system, has socially ascribed identities, relates to peers and societal institutions, and is shaped and affected by culture, norms, and expectations surrounding pornography use. In order to effectively address SPPPU and its impact on overall functioning, there needs to be a better understanding of these external influencing factors, and their interface with internal factors.

Ecological Perspective on SPPPU

Humans do not live in a vacuum. Our internal processes influence how we act, and our internal circuits are shaped by environmental influences and social learning (LeDoux 2003). Bronfenbrenner (1979, 1986) proposed an ecological model, in which the interaction between the person and environment was of the utmost importance to human development. The ecological environment has a nested structure, as different levels of the environment (e.g., micro, meso, macro) impact each other. Bronfenbrenner (1986) calls attention to how individual behavior and human development is significantly impacted by external systems, and cannot be understood without a contextual analysis. Developmental and environmental factors influence SPPPU and are integral in the understanding of this phenomena. Thus, with the ultimate goal of developing a comprehensive model of SPPPU, the ecological model will be used to summarize and organize research conducted in this area among different systems.

Ecological Microsystem: Individual Risk Factors and Identity

Overall, the individual and developmental variables mostly associated with SPPPU is identifying as a man and being an adolescent or young adult (Wetterneck et al. 2012; Wolak et al. 2007). Moreover, SPPPU has been connected to sexual dysfunction in men and decreased enjoyment in sexual activities (Park et al. 2016). In an exploratory study of pornography use among college students, Carroll et al. (2008) found that 87% of male subjects endorsed viewing pornography, whereas only 31% of women subjects endorsed similar behaviors. The authors also found that most participants found the use of pornography to be acceptable (67% of men, 49% of women). Cooper and Klein (2018) also found that nearly half (48%) of their sample endorsed using online pornography.

Gender

Wetterneck and colleagues (2012) conducted a survey study with 94 men and women regarding their use of internet pornography. The authors found significant gender differences in the sample studied. Men reported higher use of internet pornography (M = 12 h) than women (M = 5 h), and men scored significantly higher in impulsivity, compulsivity, sexual symptoms, and overall positive and negative effects of pornography than women. The authors also found that the more hours per week an individual views pornography, the more they report sexual urges and problems with sexual compulsivity. Pornography use seems to be maintained through negative reinforcement as a method of distraction from unpleasant internal events (e.g., boredom, loneliness). Significant gender differences in pornography use are also seen in college students, with men watching more pornography and approving more of pornography than women (O’Reilly et al. 2007). Although gender differences have been observed, gender as a categorical variable by itself does not explain differences in self-perceived problematic pornography use (cf. Helms et al. 2005). It is important to identify other psychosocial continuous variables that would better explain gender differences in SPPPU (e.g., interpersonal variables and social norms).

Developmental

A cross-sectional study was conducted with a nationally representative sample of 1500 youth aged between 10 and 17 years that used the internet at least once per month for the last 6 months. The majority of participants used the internet at home and school, and most commonly used the internet to play games, talk with friends, and instant messaging. Forty-two percent reported seeing pornography online over the past year, and two-thirds of those reported only unwanted exposure. The preteen boys had the highest risk for unwanted exposure, rates of wanted exposure to internet pornography increased with age, and more than one third of male internet users aged between 16 and 17 reported visiting pornography websites on purpose over the past year (Wolak et al. 2007).

Overall, although gender predicts pornography exposure in general, it does not seem to influence exposure to different types of pornography (e.g., affection, violence, dominance). A longitudinal study with a sample of 1557 Dutch adolescents found that younger adolescents were more exposed to affection-themed pornography, whereas older age and higher level of academic achievement predicted exposure to dominance-themed pornography, and hyper gender identity positively predicted exposure to violence-themed pornography (Vandenbosch 2015). It is important to note however, that although gender has been found to predict pornography exposure, it does not explain the disparity in pornography access between boys and girls. Categorical variables, such as gender and race, neglect within-group variability and are not useful as explanatory variables for psychological phenomena (Helms et al. 2005). Hence, it is important to address other continuous variables that can better explain these differences, such as interpersonal and community factors.

Sexual Dysfunction

In a recent review of literature, self-perceived problematic pornography use was found to be correlated with sexual dysfunction in men, including problems with arousal, attraction, and sexual performance (e.g., difficulty achieving orgasm, diminished libido, erectile function), decreased enjoyment of sexual intimacy and negative effects on partnered sex, preference for using pornography as opposed to partnered sex to achieve and maintain arousal, and greater brain activation in response to pornography (Park et al. 2016).

Ecological Mesosystem: Interpersonal Risk Factors

Overall, cross-sectional, longitudinal, and case studies have shown SPPPU to be linked to negative effects in interpersonal relationships, especially with sexual and romantic partners (Cotigă and Dumitrache 2015; Perry 2017; Schneider 2000). There seems to be frequent intimacy issues among self-perceived problematic pornography users, including difficulty maintaining an erection with partners, and dissatisfaction in the relationship reported by both partners (Cotigă and Dumitrache 2015). Studies have found that female romantic partners consistently report experiencing serious adverse outcomes of their partner’s problematic pornography use, including traumatic discovery of usage, feelings of betrayal, rejection and abandonment, shame and humiliation, isolation and anger, loss of self-esteem, and questioning of partners’ character (Schneider 2000; Bergner and Bridges 2002). Partners of people with SPPPU reported adverse effects on their children, which included: (a) exposure to pornography and objectification of women, (b) involvement in parental conflicts, (c) lack of attention from parents, and (d) breakup of the marriage (Schneider 2000).

Perry (2017) used data from the Portraits of American Life Study, conducted from 2006 to 2012 with a nationally representative sample of 1314 participants. The author found that frequency of pornography use in 2006 was the second strongest predictor of marital quality in 2012, with high pornography use associated with low relationship quality. The authors found, however, that although negative effects on marital quality applied to husband use of pornography, wife use of pornography seemed to predict higher marital quality. The author found that men were more likely to use pornography alone as a means for masturbation, while women were more likely to use pornography as part of sexual relations, as a way to build romantic intimacy. Exposure to pornography has also been linked to an increase in extradyadic behavior in relationships, which seems to be mediated by perceptions of the quality of alternative romantic partners (Gwinn et al. 2013).

Ecological Exosystem: Community and Institutional Risk Factors

Generally, SPPPU has been related to norms among peers that see pornography use as acceptable, engagement in offline peer support, and lack of parental guidance regarding sexual activity. A study exploring the relationship between parental mediation of pornography during adolescence and salient pornography-related norms, surveyed 308 emerging adults (18–26 years old). The accessibility of norms about pornography was measured by the time it took for participants to press a key that corresponds to the descriptive norm (i.e., whether or not they think others use pornography) or to the injunction norm (i.e., believe others think they should use pornography). Participants were more likely to view pornography when they held a salient belief that their peers both approve of viewing and regularly view pornography. Additionally, parents’ provision of rules about viewing pornography during adolescence reduced future pornography use, by means of instilling the salient belief of parent disapproval of viewing pornography (Rasmussen et al. 2016). A survey study with college students found that students who did not engage in online sexual activities were more satisfied with their “offline” life and felt more connected to friends and family. Participants that engaged in online sexual activities for informational and entertainment purposes reported being more dependent on the internet and had lower “offline” social integration (Boies et al.2004).

In a study investigating pornography-viewing habits of urban, low income, youth of color in the U.S. found that although youth reported mainly watching one-on-one sexual intercourse pornography, they also reported having seen extreme pornography (e.g., public humiliation, incest). Youth also reported that pornography was frequently watched in school in their phones or computers, with the intent to be entertained, sexual stimulation, instructional purposes, and to alleviate boredom. Youth reported they felt pressure to imitate content seen in pornography in dating relationships, and unable to discuss sexual activity with their parents. Participants reported their parents were unsupportive of pornography use but did not have the tools to discuss or monitor pornography use (Rothman et al. 2015).

Ecological Macrosystem: Societal and Public Policy Risk Factors

There is strong evidence consistent across experimental and nonexperimental studies and across different populations that pornography use is a risk factor for aggressive outcomes and violence against women, especially for men who also have other risk factors and use pornography frequently (Kingston et al. 2009). Multiple meta-analyses have found moderate to large effect sizes for sexual deviancy, sexual assault perpetration, intimate relationships problems, and increased rape myths acceptance for participants frequently exposed to pornography, as well as positive associations between men’s pornography use and their attitudes supporting violence against women (Hald et al. 2010; Wright et al. 2016; Wright et al. 2017). Additionally, college men who view pornography seem to be significantly less likely to intervene as a bystander, report an increased behavioral intent to rape, and are more likely to believe rape myths (Foubert et al. 2011).

The connection between pornography use and violence against women is well-established in the literature. In a content analysis of popular pornography videos, Bridges et al. (2010) found high levels of aggression present, both verbal (48% of scenes) and physical (88% of scenes). Most depicted aggression included spanking, gagging, slapping, and name-calling, and perpetrators were usually male, whereas targets were overwhelmingly female. Targets of aggression mostly showed pleasure or responded neutrally. This finding contributes to the evidence of systemic depiction and normalization of violence against women in pornography.

The American Psychological Association Task Force on Sexualization of Girls (2010) reviewed the literature on the sexualization of women and girls, and consequences and impact in the individual and societal level. According to the report, “if girls learn that sexualized behavior and appearance are approved of and rewarded by society and by the people (e.g., peers) whose opinions matter most to them, they are likely to internalize these standards, thus engaging in self-sexualization” (p. 2). This self-sexualization affects women’s mental and physical health. Social problems that disproportionately affect girls, including violence, sexual exploitation, forms of pornography, and sex trafficking is usually maintained and increased by continued sexualization of girls.

Aside from the sexualization and objectification of women, pornography has been proposed to maintain oppressive societal systems, including racism and sexism (Cowan and Campbell 1994; DeKeseredy and Hall-Sanchez 2017; Garos et al. 2004). Given that online sexual explicit materials can impact viewers’ sexual script, it can lead to stereotypical sexual perception and attitudes. Furthermore, many people use ethnicity labels to looks for specific pornography. A content analysis of depicted sexual behaviors in a sample of videos from the category “Asian Women” taken from the most visited pornography website in the United States was conducted to better understand how Asian women are being portrayed when compared to other categories of pornographic material. The researchers found that Asian women were depicted very differently from women in other categories of pornography, and included being treated less aggressively, less objectified, having lower agency in sexual activities, and seen as innocent, submissive, and docile (Zhou and Paul 2016).

Summary of the Ecological Model for SPPPU

When considering developmental and environmental variables, the issue of SPPPU becomes more complex and comprehensive. Young men are widely at more risk for watching pornography online, and therefore more at risk for developing SPPPU. This gendered phenomenon is influenced and maintained by sexist attitudes in society and encouragement of toxic masculinity. Toxic masculinity is defined by the “constellation of socially regressive male traits that serve to foster domination, the devaluation of women, homophobia, and wanton violence” (Kupers 2005, p. 714). Toxic masculinity, sexism, and stereotypes have been shown to be consistently portrayed in pornographic materials, which are accessed online and used by adolescents and young adults for informational purposes and sexual arousal. This is also influenced by moralistic beliefs regarding sexuality and difficulty in discussing healthy sexuality in schools and by parents. This usually leads youth to look for knowledge online, which is also maintained by peer norms of acceptance and encouragement to watch pornography among men. This constant exposure to pornography engenders and maintains rape myths, misogyny, sexualization of women, violence against women, and toxic masculinity in general. The combination of these ecological variables appear to contribute to the development of self-perceived problematic pornography use. Moreover, problematic pornography use appears to affect interpersonal relationships and generates intimacy issues, sexual dysfunction and difficulty with arousal, approach/avoidance tendencies, and difficulty with executive control.

Integrative Model of SPPPU

Self-perceived problematic pornography use appears to be a complex phenomenon, impacted by both individual (e.g., molecules, circuits, behavior) and social level variables (e.g., toxic masculinity, gender roles). By combining available evidence from both an ecological and RDoC perspectives, we propose an integrative model, highlighting how these variables intersect and impact SPPPU (Fig. 2). The combination of peer and societal encouragement and reinforcement for watching pornography may lead to neuroplasticity and changes in the reward system associated with arousal in young men. Men with SPPPU usually report difficulties in arousal and need to watch pornography to achieve orgasm, which might be directly caused by the inhibition of dopamine neurons after dysregulation of the mesolimbic dopaminergic system, which generates an aversive state and negative reward for watching pornography. By understanding the complex relationship among the variables impacted by SPPPU, future research can be geared toward how these variables intersect, aiding in future remedial and preventive measures to alleviate the deleterious effects of SPPPU. In developing an integrative model of SPPPU we hope to foster a critical analysis of pornography research and consumption (Smith and Attwood 2014), opposed to a polarized discussion of pro- and anti-pornography, with the intent that practitioners and researchers are able to better integrate levels of analysis in developing treatment strategies and investigating the impact of self-perceived problematic pornography use.

Fig. 2
figure 2

Integrated model of different systems involved in self-perceived problematic pornography, integrating levels of analyses from both the RDoC and ecological perspectives

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Discussion

Given the impact and intersectionality of different units of analysis in SPPPU, the current literature was organized using the RDoC and ecological models. By understanding the connections between molecules, circuits, physiology, behavior, ascribed social identities, interpersonal relationships, community norms, and societal implications of SPPPU, future research and treatment should focus on the multifaceted nature of this phenomena. We hope that this model of SPPPU (Fig. 2) can better guide future research, helping to develop more adequate and effective ways of preventing and treating SPPPU.

Implications for Research and Treatment

To our knowledge, there is little evidence for effective treatments for self-perceived problematic pornography use up to date. Although case studies on pharmacological treatments (e.g., naltrexone; Bostwick and Bucci 2008; Capurso 2017) and psychological treatments (e.g., ACT, CBT; Hardy et al. 2010; Twohig and Crosby 2010) have been researched, there is still a lack of evidence to support the effectiveness of these treatments due to small sample sizes and limited research. Moreover, there are ambiguous findings in the literature due to disagreement on treatment goals and lack of a parsimonious criteria for SPPPU, which has consequences for the standardization of procedures (Sniewski et al. 2018).

Given the current scarcity of evidence for effective treatments, there is a need for research in this area that addresses the multiplicity of factors related to SPPPU, and exploration of the interface across units of analysis as it relates to treatment and reduction of negative symptoms in people with SPPPU. Future research should make an effort to integrate different methods, and research treatment strategies that focuses on brain changes in reward systems in relation to preventative and remedial interventions in environmental systems that relate to SPPPU. Promising prevention intervention areas for treatment of SPPPU would be to implement media literacy interventions in schools, with specific interventions to increase executive control. Further, to address the societal expectations regarding SPPPU, interventions focusing on toxic masculinity in college students, addressing approach/avoidance tendencies, can be particularly helpful in combatting the potential harmful effects of SPPPU. Additionally, clinicians should be mindful of different societal, community, interpersonal, and individual variables that affect SPPPU when conducting treatment and setting goals for therapy. Assessing for well-being, approach/avoidance behavior, toxic masculinity, conditioning of neutral stimulus, norms regarding pornography use among peers and family members, and dissatisfaction in relationships may provide insight to the experiences of clients presenting with SPPPU.

Limitations of Literature

The majority of studies reviewed used biological data, mostly focusing on brain imaging findings. Although these findings are useful in contextualizing the biological underpinnings of SPPPU, they only provide correlational data (i.e., what systems of the brain are activated when viewing pornographic material). Future studies should address this gap in the literature investigating causal relationship between SPPPU and neuroplasticity and behavioral change, specifically using longitudinal and experimental methods and integrating self-report, behavioral observations, and physiological data. It is important to foster different methodologies and approaches to studying SPPPU, as it is a phenomenon with social and individual implications.

Furthermore, most of the reviewed studies emphasized internal validity but neglected to address concerns regarding external validity. Given the homogeneity of subjects researched (i.e., white heterosexual men), these findings may not be generalizable to the overall population. It is important to focus on the external validity of studies to provide more socially responsible research that can be clinically useful for practitioners (Sue 1999). Further research should focus on how ethnic, gender, and sexual identities can moderate the experience SPPPU, and if these models are generalizable to different cultural groups.

Choudhury et al. (2009) propose viewing neuroscience as a cultural activity and identify different methods that can be used to analyze how neuroscience influences society. The authors suggest engaging in the following critical activities when conducting research: (a) historical contextualization of the development of neurosciences (i.e., clues about why this may occur), (b) socio-economic drivers of research programs (i.e., why does a certain question about the brain is more significant than others), (c) ethnographic analysis of lab practices (i.e., examination of the scientific community and ‘collective eye’ that is trained to see and determine what counts), (d) conceptual and technical scrutiny of methodologies, paradigms, data analysis and interpretive frameworks (i.e., are scientific standards met and are results and implications judged appropriately), (e) media representations and their interaction with processes of research (i.e., how this knowledge is processes and used), (f) engagement with the mechanisms of agenda setting in the neurosciences (i.e., identify and track economic influences), and (g) the implementation of alternative approaches, methods, designs and interpretations in neuroscientific research. The authors relate the main goal of a critical neuroscience is to develop a more complete self-understanding of the social implications of research and its uses, which can provide feedback to neuroscience in general. In that effort, critical neuroscience can be a useful paradigm to guide future studies on SPPPU.

Limitations of this Review

The goal of this review was to develop an integrated model of SPPPU through an integrative review, to guide and contextualize current and future research. Hence, although an extensive literature review was conducted, this was not a systematic review of literature. Further, only research published in peer-reviewed journals were included in this integrative review. As there is a publication bias toward studies with significant results (Simonsohn et al. 2014), it might be possible that research with nonsignificant findings could have further informed the model proposed. Another limitation of note is that studies reviewed were all published in the English language alone, which can have contributed to non-generalizability of this research to countries other than the USA.

Future Directions

An important aim of this integrative review is to combine the literature pertaining to self-perceived problematic pornography use across different units of analysis, from molecules to societal factors, to inform treatment and future research. The ultimate goal is to stimulate translational efforts in RDoC research and draw attention to the intersectionality of the units of analysis, using an ecological framework. Self-perceived problematic pornography use is a social phenomenon, which has been found to be associated with sexism, stereotypes, misogyny, and violence against women. However, the social implications alone are not enough to explain SPPPU, as the phenomenon is also connected to biological sexual activity that activates a natural reward system in the brain, which can have negative effects in the individual level and amplify societal implications. Therefore, our goal is not to oppose the pornography industry, but to promote a model that can be used to critically analyze pornography research and content. Through this critical lens, providers can better understand the SPPPU phenomenon, which can have significant adverse effects to a small proportion of pornography users. We hope that future studies on the prevention and treatment of SPPPU can look at this phenomenon holistically, integrating different units and levels of analysis.