Introduction

Happiness is a fuzzy concept that has been defined in many ways by many researchers. Related concepts are well-being, gladness, satisfaction, pleasure, quality of life and flourishing. It is a mental or emotional state of comfort defined by positive or pleasant emotions ranging from contentment to intense joy. A variety of biological, psychological, religious and philosophical approaches had been attempted to define happiness and identify its sources. Various researchers, research groups, including positive psychology, are employing the scientific method to research questions about what happiness is and how it might be attained. In fact, we all want to be happy and hence we do meditation, yoga and exercise. We think that if we had more money, a higher IQ, a better marriage, more loyal friends, more successful children, lived in a better climate, a new expensive car and a new luxurious house, etc., we would be happier. We also think that if we can shop whatever we want, eat whatever we like, obtain whatever we desire, get enough sleep, exercise and sex, high self-esteem and optimism, we would be happy.

But the reality is totally different than the above ideas. There is a clear consensus in the literature of happiness that people who have religious or spiritual beliefs are happier than those who do not, no matter what they physically possess. This is because religious beliefs give people a sense of meaning of life, a sense of well-being or comfort and a genuine social network. Religious belief makes people helpful, productive, loyal, honest, truthful, sincere, hard-working and accountable. It also provides better physical shape, health and mental peace. Often, the people who are religious have a community, a place of worship (mosque, church, temple, synagogue, etc.), and holy book study groups (Qur’an, Bible, Gita, Torah, etc.). It is the social support network that fulfills human desires. Thus a religious person could easily be working in a good environment, joining a book club or belonging to a neighborhood watch. It is the sense and feeling that people are mutually looking after one another which matters a lot for human happiness. People who are believers have a certain mind-set: the power of prayer, the belief in an afterlife, the sense of mutually looking after one another and there is a higher power that things happen for a reason. This mind-set helps people to make sense of tragedy, struggles and loss. One can believe “God only tests you with what you can handle,” or “There is a silver lining in the suffering.” Religion is about helping other people and having others looking after you.

The current research paper provides a broad and systematic literature review of the work on the relationship between religion and happiness. “Research Methodology” section provides the methodology used for this review. “Literature Review” section contains the detailed review of all the materials obtained in this research. “Observation” section illustrates the observations that can be made from the review. A brief discussion has been provided in “Discussion” section. “Conclusion and Future Works” section concludes the overall study.

Research Methodology

The current study is a systematic literature review (SLR) on the issue of relationship between religious belief and happiness. The procedure for the SLR was based on that of Kitchenham (Kitchenham 2004; Kitchenham and Charters 2007). Kitchenham (2004) defined SLR as a systematic procedure to identify, evaluate and interpret all the research relevant to a given research question, topic or area of interest. SLR was divided into three steps, and they have been elaborated below.

  • Planning The resources and publications were initially collected from sources like Google Scholar, Scopus, ScienceDirect, ProQuest, Taylor & Francis, Wiley and Springer, etc. The keywords that were implemented were words like religiosity, happiness, religiousness, religious belief, satisfaction, well-being, health, quality of life and spirituality. By going through the title, abstract and introduction of the papers, the selection and rejection decision was taken. To find only the latest literature for the review, a strict timeline from 1996 to 2015 was used.

  • Conducting Out of the 115 research papers obtained, 85 fitted with the research topic. These were further screened to obtain 77 papers were in the scope of this paper.

  • Reporting The 77 papers were read and studied very carefully and elaborately. Seventy-three of them were found to be surveys and the remaining four were reviews. The materials obtained for our study were organized along the timeline and presented accordingly in this review paper.

Literature Review

During the last two decades, a number of researches have been put their attention and effort toward understanding the relationship between religion and happiness. The religion was evaluated using parameters like religiosity, religiousness, religious belief, attendance to place of worship, knowledge about the respective religious belief, intrinsic behavior and extrinsic behavior. The happiness has been measured by the parameters like satisfaction in life, love of life, well-being, quality of life, mental health and physical health. To evaluate the happiness, scales like Oxford Happiness Inventory and Satisfaction with Life Scale were used, while the religiousness was measured using self-evaluation, Francis scale and other models. This section provides a comprehensive systematic literature review considering the last two decades (1996–2015) by analyzing the studies in terms of religion, geographical location, scales implemented and the significance of the relationship.

Reviews

Over the last two decades, the topic of religiosity and happiness has gained much importance. Subsequently, this has led to enough literature that was used by some researchers to review the status of the topic. Lewis and Cruise (2006) conducted a literature review and categorized the text into consensus, contradictions, comments and concerns. The consensus was the implementation of common measuring scales that facilitates having a standard measurement and comparison. The major contradiction was the variation between positive and no relationship between religion and happiness among different authors. Some of the concerns are the samples being limited and cross-sectional and the lack of clear definition for religiosity and happiness.

A more recent review was conducted by Tay et al. (2014) taking an international perspective. It showed that although there were many researchers and atheists, who were trying to demonstrate religion as irrelevant, the majority of the human regarded religion as an important part of their daily lives to obtain peace and happiness. Vishkin et al. (2014) provided another literature review in the same year. They proposed and explained that religion is a major tool for emotion regulation and happiness by analyzing the concepts of joy, hatred, gratitude, awe and guilt from a religious perspective. Religion sets the emotion goals and the emotions are regulated using a combination of intrinsic and extrinsic processes of religion.

Religion

The major religions in the world are Christianity, Islam, Hinduism, Buddhism and Judaism (Hackett et al. 2012). All of these religions have been studied for the relationship between religiousness and happiness. Major study has been conducted on Christianity and Islam, while small number of researches has been seen on Hinduism, Buddhism and Judaism. The following subsections discuss the findings in each religious group.

Christianity

Christianity was the earliest religion that was studied by the researchers to find its significance on happiness and satisfaction in life. The findings by Robbins and Francis (1996) using a sample of 360 undergraduate students demonstrated a significant positive relationship between religion and happiness as early as in 1996. On the other hand, Lewis et al. (1996) found no relationship between religiosity and satisfaction in life when they surveyed a group of 150 students in the same year. A contradiction to this result was presented by Francis and Lester (1997) when a survey of 212 undergraduate students showed that the happiest individuals were found to be the ones who were more religious and extravert and less neurotic. Lewis et al. (1997) countered the results again by the survey of 221 undergraduate students and finding no evidence of a relationship between religiosity and happiness.

A dissimilar approach was used by a different researcher, Levin and Chatters (1998), who used the data from earlier national surveys with a total sample size of 4792 older adults and grouped them in terms of gender, age, race, marital status, education level and geographical region. The analysis showed a significant and positive relationship of organizational religiosity with well-being and health. French and Joseph (1999) showed that religiosity also led to well-being since it helped in the realization of purpose of life in the 101 students surveyed. In the subsequent year, Lewis et al. (2000) consolidated on their earlier outcome by conducting a survey using samples of priests and members of the Anglican Church to indicate no relationship between religiosity and happiness. Furthermore, a similar conclusion was also obtained by Argyle and Hills (2000) after analyzing 364 respondents. A converse approach was used by Maltby and Day (2000), who studied the relationship of religiousness with depression rather than that with happiness. The survey consisting of 360 students showed that high level of extrinsic orientation and low level of intrinsic orientation led to higher depressive symptoms, which meant that religiousness led to happiness.

The concept of tripartite was introduced by Compton (2001) to study the relationship between religiousness, mental health and happiness. His test over 242 students showed that the tripartite factor holds true and religiosity has a positive impact on mental health and happiness. Furthermore, religion was demonstrated as a source that explained the purpose of life and led to well-being, happiness and better life expectancy in Ferriss (2002). A converse result was found by Lewis (2002) after studying 154 Christian undergraduate students and concluding that no evidence was found to show impact of religiosity over happiness. Likewise, O’Connor et al. (2003) studied 177 undergraduate students to find no significance between religion, stress and psychological distress. A contradiction to O’Connor et al. was provided in the next year (i.e., 2004) by surveying 246 undergraduate students (Francis et al. 2004b). Additionally, testing the two major sections of Christianity, 1206 Catholic and 1464 Protestant adolescents, the relationship between religiousness and the perception of purpose in life revealed to be positively significant (Robbins and Francis 2005). Thus, religiosity led to happiness since purpose in life provides a direct link to happiness as discussed in Ferriss (2002; French and Joseph 1999; Lewis et al. 1997).

Lelkes (2006) added the concept of economic freedom with religiousness and happiness using a sample of 9167. The study revealed a very interesting result that religion had a positive effect on the happiness, while the monetary status and the increase in the economic freedom were insignificant for life satisfaction. Thus, opposing the popular perception, it was concluded that the economic transformation led to lower happiness. Alternatively, Robbins et al. (2008) added the factor of prayer frequency to test 131 students and find a significantly positive relationship between prayer and happiness. Afterward, a new perspective into this field was brought about by Idler et al. (2009) surveying 499 elderly people from the USA in the last year of their lives. The sample consisted individuals who died with 12 months of the interview in the timeframe of 1982–1994. It was proved that being more religious during the last year of the lives led to better quality of life.

The research in this topic also brought about the interest of research students and with this intension Malpere (2010) conducted a comprehensive study and survey toward her Master’s thesis in 2010. A small sample of 44 government employees demonstrated a contradiction to most other researchers as the analysis of the responses failed to find any significance between religiosity, spirituality and happiness. Additionally, the Master’s thesis by Pena (2013) used 59 adults on Facebook to signify the above conclusion once again.

Opfinger and Gundlach (2011) brought a different approach into this research by considering other factors to happiness in addition to religiosity and comparing their dependence. High religiosity showed higher degree of happiness when other factors of happiness were kept constant and at a constant level of happiness religiosity could be replaced by other commodities like increase in income (Gundlach and Opfinger 2013).

In the current years, it has been observed that the study of topic of religiousness and happiness in the context of Christianity has been declining, while it has gained interest in other religions like Islam and Hinduism. The following sections thus discuss such researches.

Islam

One of the first surveys to study the Muslim population was in 2004 when a sample of 973 respondents from various backgrounds was used to show that religiosity was directly proportional to the happiness (Suhail and Chaudhry 2004). However, the above researchers did not continue for more surveys, and Abdel-Khalek took a great interest in this topic and studied that Muslim population of various countries and ages. In 2006, Abdel-Khalek surveyed 2210 Muslim undergraduate students and demonstrated that religiosity had a significant positive effect on the happiness, physical health and mental health (Abdel-Khalek 2006). In continuation, Abdel-Khalek and Naceur (2007) studied 244 students in a different setting and confirmed that religiosity had a positive effect on the happiness. They also found that women were more satisfied in life than men. Another survey by Abdel-Khalek (2007) was on a sample of Muslim adolescents, which revealed that among both the genders, the religiosity had a compelling and positive relationship with happiness, mental and physical health, while a negative relationship with anxiety and depression. In addition to this, 424 employees were also surveyed to obtain similar positive results (Abdel-Khalek 2008). Abdel-Khalek and Lester (2009) proved their claim once again when they surveyed 162 undergraduate students and demonstrated a noticeable association between religion and happiness. Abdel-Khalek brought about many more research outputs on the relationship between religiosity and happiness and will be discussed in the coming sections. As a summary to all the research done by him and others over the Muslim population, Abdel-Khalek (2014b) complied a comprehensive study. The paper discussed the various aspects of Islam like the Quran, prophet Muhammed, pillars of Islam and the statistical proof of religious Muslims being happier.

In a like manner with earlier researchers, Hafeez and Rafique (2013) surveyed 60 senior citizens in old age homes and found that psychological well-being could be positively predicted by the religiosity. A similar study was conducted by surveying 100 elderly to demonstrate that religiosity had a positive effect on life satisfaction (Gull and Dawood 2013).

In another study, 271 Muslim undergraduate students of Medical Sciences were surveyed to show that higher religiosity led to higher happiness (Sahraian et al. 2013). It was then recommended to take religiosity into account in general mental health and well-being programs. Furthermore, a significant positive link between happiness, social relationship and religious attitude was observed by surveying university 370 students (Jesarati et al. 2013). The study on the Sunni sect of Islam also proved a significant relationship between religious personality and mental health (Parveen et al. 2014).

Hinduism

The study on the concerned topic among the followers of Hinduism is in its initial stages and demands further research and analysis. The first survey on the followers of Hinduism was conducted by recruiting 154 pilgrims from the Ardh-Kumbh Mela pilgrimage held in 2007 at the bank of river Ganga in Allahabad in India (Maheshwari and Singh 2009). It showed a clear indication that religiousness led to higher happiness and life satisfaction among. Another study was conducted by surveying 171 older adults and demonstrated a significant and positive correlation between spirituality on the well-being (Gupta and Chadha 2014).

Buddhism

Buddhism is a major religion in the eastern part of Asia. The first study on people associated with Buddhism was done by studying 1599 responses from the Korean General Social Survey of 2009 (Jung 2014). The analysis showed that there is a slight but noticeably significant relationship between religious attendance and happiness, especially for the women. Another study took the responses from a total of 1881 people to find that organizational religious acts had no significance on happiness, while personal religiosity like being thankful, praying daily and repenting led to higher happiness. (Liu et al. 2012).

Judaism

After Christianity and Islam, Judaism is yet another major Abrahamic religion and is mainly practiced in Israel. In case of Judaism, positive correlation was discovered, between religiousness and happiness, by Francis and Katz (2002) in their survey of a sample of 298 Jewish female undergraduate students. As a continuation to the above survey, Francis et al. (2004a) surveyed the 203 male students and proved the same results. The results were further consolidated with the survey on the 284 females (Francis et al. 2014).

Cross-Religion

The cross-religion study of the concerned topic of interest is a challenging task. Every religion has its own unique kind practices and signs of piety. The other challenge is that the regions with comparable populations of multiple religions ares rare. Rather, in most regions, the follower of a single religion forms a vast majority, while followers of other religions form a small minority. Thus a cross-religious study is rare in this case. In one of the studies, a cross-country and cross-cultural survey on university students over four countries (Ghana, Nigeria, North Ireland and Swaziland) (Dorahy et al. 1998) was conducted. The analysis showed a positive significance between religiosity and life satisfaction for most males, while no significance was found among the females. It is interesting to note that only Ghana and Nigeria had some Muslim population, and both these countries showed higher attitude toward God and higher association with life satisfaction. The other notable study was done by Abdel-Khalek and Lester (2007), who compared the responses of 460 Muslim and 274 Christian college students. Although there were differences in various factors among the two samples, religiosity had a significant positive effect on physical health, mental health and optimism for both. To compare better, equal number of Muslim and Christian undergraduate students were surveyed (Abdel-Khalek 2010a). The analysis once gain reinforced the notion that religiosity leads to better quality of life and subjective well-being. The study also highlighted the dominant score of the Muslim (Arab) samples as compared to that of Christian (American), using which the authors claim that Islam was higher in importance to its believers as compared to other people for their respective religions. Thus, Muslims were happier and more satisfaction in life compared to Christians.

Geographical Location

The literature has shown that the study on the relationship between religiousness and happiness was initiated in the West, specifically the UK and the USA. After about a decade of rigorous study in various parts of UK and the USA, the attention slowly shifted worldwide, especially to Asia and Africa. The Middle East as well as the Oceania regions has also found consideration and analysis. The following sections discuss the studies conducted in various regions of the world.

Europe

Most of the initial studies in the concerned topic has been studied in the European lands. Notably, numerous regions of the UK have been studied carefully. Positive results were seen at Wales (Francis et al. 2003a, 2004b; Robbins and Francis 1996; Robbins et al. 2008) and Sheffield (Maltby and Day 2000). On the other hand, no significance was seen in Ulster (Lewis et al. 1997), North England (Lewis et al. 2000), Oxfordshire (Argyle and Hills 2000), Leeds and Strathclyde (O’Connor et al. 2003). Additionally, positive as well as no significance was observed in Essex (French and Joseph 1999; Lewis et al. 1997) and North Ireland (Dorahy et al. 1998; Francis et al. 2004b; Lewis 2002; Lewis et al. 1996; Robbins and Francis 2005) when different authors studied the same regions.

Apart from the UK, the relationship has been studied in Germany by surveying 331 students from University of Würzburg and demonstrating no significance between religion and happiness (Francis et al. 2003b). Similarly, Estonian students provided the same outcomes when 150 responses from two different universities were studied (Francis et al. 2012). Furthermore, 274 Slovakian students also had no significance between religiousness and happiness (Halama et al. 2010). On the contrary, analysis of 196 high school students from Turkey showed that religious attendance and prayers indicated life satisfaction, happiness and well-being (Eryilmaz 2015). The author also listed the factors like feeling of being rewarded, security, unity and building intimacy to be the reasons behind this positive relationship. Positive results were also obtained in Hungary (Halama et al. 2010; Lelkes 2006).

Americas

Among the countries in the Americas, the USA has been the country with most interest. Various researchers have studied the vast country since 1997. The literature has shown that the majority of the studies have shown a positive relationship between religiosity and happiness (Compton 2001; Ferriss 2002; Francis and Lester 1997; Idler et al. 2009; Levin and Chatters 1998). On the contradictory side is the study by Malpere (2010) studied religion and spirituality with happiness among 44 adults on Facebook to find not significance among the concepts. The other study in the continent came from Canada by surveying 320 children of age 8–12 years and their respective parents using relevant scales (Holder et al. 2010). The analysis clearly demonstrated that regardless of religious practice, spirituality formed the strongest predictor for happiness.

Asia

The enormous continent of Asia consists of large populations from all major religions of the world. Although the study on the regions in this continent has started much later that the European and American counterparts, the current literature shows a great number of articles have been published in the recent times.

Among the regions of Asia, the Middle East has been observed to be the region with most studies and surveys. Israel, the only country with a majority population following Judaism, has shown positive relationship between religion and happiness in every instance that it was studied (Francis and Katz 2002; Francis et al. 2004a, 2014). Similar results were also seen among the Muslim population in Kuwait from various ages, backgrounds and gender (Abdel-Khalek 2006, 2007, 2008, 2010a, b, 2011a, 2012b; Abdel-Khalek and Lester 2009). In addition, the religious people were found to be happier, healthier and less depressed when 7211 Saudi children and adolescents were studied (Abdel-Khalek 2009). Males were shown to be more religious and satisfied with life than females. Furthermore, the survey of 372 adolescents and 246 young adult students in Qatar showed that both, males and females were happier, healthier and more satisfied in life when they considered themselves religious (Abdel-Khalek 2013a, b). Similarly, the two studies on Lebanon consisting of 239 and 476 young adults revealed that the religious people were happier and healthier (Abdel-Khalek 2014a, 2015).

The other major Middle East country that was studied was Iran. One of the earliest studies on Iran was done by analyzing 1491 professional employees like doctors, lawyers, engineers and teachers in the country (Aghili and Venkatesh Kumar 2008). The analysis clearly demonstrated a positive link between religiousness and happiness. The result was consolidated further when 301 students from Shiraz University showed that religiosity had a positive effect, while neuroticism had a negative effect on happiness (Moltafet et al. 2010). The mediation between these two aspects was found to be obtained by religious orientation (extrinsic and intrinsic). A different approach was observed when religious orientation was studied with the traits of anxiety and depression (Amrai et al. 2011). They recruited 347 students from the University of Tehran and the analysis indicated a negative link for religiosity with anxiety and depression, thus positive link to happiness. Staying consistent with most other researchers, it proved that Iran was studied for the sixth time with a sample size of 358 undergraduate students (Bayani 2014). In consistence to the earlier results on Iran, the analysis showed that religiosity had a positive impact on the happiness.

The Indian sub-continent majorly consists of Muslims and Hindus. Studies in India as well ask Pakistan have shown that both Muslims (Gull and Dawood 2013; Hafeez and Rafique 2013; Parveen et al. 2014; Suhail and Chaudhry 2004) and Hindus (Abdel-Khalek and Singh 2014; Gupta and Chadha 2014; Maheshwari and Singh 2009) of variable ages, cultures and backgrounds were happier when they observed more religiousness in their lives.

The eastern Asian countries have also been a subject of interest among some researchers in the recent times. The survey and analysis have been carried out in Taiwan (Liu et al. 2012) and South Korea (Jung 2014). In the case of Taiwan, it was found that the relationship was positive among all people, while in South Korea, the relationship was positive only among the women.

Africa and Australia

The continent of Africa consists of varied religious population as one moves from the north to the south. The first study considered the central African countries of Ghana, Nigeria and Swaziland and found in general that religiousness had positive effect on happiness among the men (Dorahy et al. 1998). Additionally, the Muslim students in Algeria as well as Egypt were observed to be happier when more religious (Abdel-Khalek 2011b; Abdel-Khalek and Naceur 2007). The only study on Ethiopia was accomplished by the survey of 214 elderly people (Hamren et al. 2015). The analysis proved that religion and spirituality had a positive effect on the quality of life among the Ethiopians and thus proposed that religiousness could alleviate the deprivation in the under-developed country.

The study on Australia is in its initial stage and only two notable surveys have been observed in the literature. The first study on Australia surveyed three different samples with a total of 1952 respondents (Fisher 2013). The analysis showed that the closeness to God had a significant and positive effect on happiness irrespective of personality and age. The second study on Australian population was conducted by using the data from national surveys conducted in 2004, 2007 and 2010 with a sample size of 28,962 adults (Kortt et al. 2015). Religiosity and life satisfaction showed a positive significance between them.

Cross Region

The cross-regional study has been a topic of interest and scrutiny among a number of researches. Some research was conducted by studying the national databases while others have used self-designed specific surveys. Another contrast was that some were used to compare the religiosity and happiness in between different countries and others were conducted to obtain a general consensus on the topic.

One of the first comparative was between the adults in US and Singapore where it was discovered that in both the countries, materialism had a negative effect on happiness and the quest to satisfaction in life by material acquisition was a painful cycle (Swinyard et al. 2001). Specifically, the practice of religion was identified as the primary source of happiness. More importantly, inner religiosity led to higher happiness as compared to considering religion just as a social act. In addition, a comparative study of Slovak and Hungarian students showed that the Hungarian sample had a positive link between religiosity and happiness while the Slovak students related religiosity only to meaning of life (Halama et al. 2010). Consequently, it demonstrated a concern that religiosity and happiness may also be culture dependent. Moreover, comparative studies were also done using parameters like religiosity, well-being, health, depression and satisfaction in life by surveying 1937 Kuwaiti and 1009 Palestinian children (Abdel-Khalek and Eid 2011). Eventually, due to the fact that Kuwaitis were found to be more religious than their Palestinian counterparts, they were found to be happier. A similar comparison between the samples of 577 Egyptian and 674 Kuwaiti students showed that the Kuwaitis were happier and more religious than the Egyptians (Abdel-Khalek 2012a). In conclusion, the religiousness was a source of happiness, better mental health and well-being.

Multi-regional, multi-religious comparison conducted between Kuwait and USA was done by surveying 154 undergraduate students from each country, and it revealed that the religiosity had a positive impact on happiness in both the samples (Abdel-Khalek and Lester 2013). A recent study took a sample of 264 Israeli-Palestinian students in college (Abu-Raiya and Agbaria 2015). The inquiry demonstrated a positive impact of religiousness in happiness and emotions.

One of the general studies was conducted by analyzing samples from 60 countries to discover that religious fragmentation led to lower happiness among the population (Mookerjee and Beron 2005). It is the consequence of the distrust, suspicion, jealousy, hatred and uncertainty fragmentation creates among the people. An interesting, innovative and vital understanding was obtained by Opfinger and Gundlach when they conducted a cross-country survey of 93 countries using the data from World Values Survey from 1982 to 2000 (Opfinger and Gundlach 2011). They discovered that religiosity had a U-shaped significance on happiness. Keeping the parameter of income constant, a person could achieve happiness whether by following the religion piously or by not following it all. But the people with an intermediate level of religiousness are observed to be less happy. It has also been noticed that the religiosity decreases with the increase in income.

Scales Implemented

The evaluation and analysis of the surveys by most of the researchers depended upon the scales and questionnaires implemented in the study. The scales used could be divided into two types: one that was used to measure the religiousness of an individual and the other was to measure the traits of happiness and well-being. In the context of religiousness, the most used method by the authors was to implement the self-evaluation of each individual about his/her religiousness, example (Abdel-Khalek 2009; Abdel-Khalek and Lester 2007). Although this method was simple and quick to complete, it did not always provide a universal and standardized level of religiousness. A more precise but longer questionnaire used by authors was that which asked the respondent about various religious acts and practices based on the individual’s belief. Some of the scales used were Intrinsic Religious Motivation (Abdel-Khalek 2007), Religious Attitude Questionnaire (Sahraian et al. 2013), Francis scale of Attitude toward Christianity (Francis and Lester 1997; Francis et al. 2003a, 2004b; Halama et al. 2010; Lewis et al. 1997, 2000; O’Connor et al. 2003; Robbins and Francis 1996), Religious Attitudes Scale (Dorahy et al. 1998), Katz–Francis Scale of Attitude toward Judaism (Francis and Katz 2002; Francis et al. 2004a, Francis et al. 2014), Spiritual Well-Being Questionnaire, Intrinsic-Extrinsic Religious Orientation Scale (Moltafet et al. 2010) and Religiosity Orientation Scale (Bayani 2014; Jesarati et al. 2013).

The second important parameter in this research is the measurement of the level of happiness and well-being in the individual. The most elaborately used scales were the Oxford Happiness Inventory (Abdel-Khalek 2015; Francis et al. 2014; French and Joseph 1999; Jesarati et al. 2013; Moltafet et al. 2010; Robbins and Francis 1996) and the Depression-Happiness Scale (Bayani 2014; Lewis et al. 1997, 2000). Although all the studies using the OHI generated a positive significance, The DHS has shown to provide positive as well as no significance in some cases. One of the studies was by Lewis et al. (2005), when they surveyed 138 adults from the UK using both OHI and DHS. The analysis using OHI demonstrated a significant relationship between religion and happiness but the DHS showed no relationship. This was justified by the argument that religiosity brings more happiness and life satisfaction when it is intrinsic rather than extrinsic. On the other side, the implementation of both OHI and DHS by French and Joseph (1999) showed positive significance irrespective of the scale. Other scales that were used are Purpose in Life Test (Halama et al. 2010; Lewis et al. 1996), Index of Self-Actualization (French and Joseph 1999), Somatic Symptoms Inventory (Abdel-Khalek 2006), Kuwait University Anxiety Scale (Abdel-Khalek and Lester 2007), Quality of Life (Ferriss 2002), Satisfaction With Life scale (Abdel-Khalek 2015), Eysenck Personality Questionnaire (Fisher 2013; Francis et al. 2014), Beck Depression Inventory (Amrai et al. 2011), General Health Questionnaire Francis et al. (2004b) and Self-Esteem Scale (Suhail and Chaudhry 2004).

Observation

Based on the review conducted, various observations were made using the vital data. The data were categorized on the basis of region and religion.

Religion

As seen in Table 1, Christianity is the most studied religion, immediately followed by Islam. The table shows that no significance was observed only in a few studies on Christianity, while all the studies on other religions always showed positive relation.

Table 1 Religion-wise data and results
Full size table

Region

As seen in Table 2, it is observed that the most of the study was conducted in UK and the results were mixed. The study to find no correlation between religion and happiness were just one each for USA and Germany. As a majority, the Asian countries seemed to be the most happy by being religious, especially those of the Middle East.

Table 2 Country-wise data and results
Full size table

Discussion

Based on the literature review conducted, it can be noticed that convincing and legitimate cross-religious studies have not yet been conducted by any authors. Some of the efforts toward this were seen in (Gundlach and Opfinger 2013; Opfinger and Gundlach 2011). But none of these except (Abdel-Khalek and Lester 2013, 2007) and (Abdel-Khalek 2012a; Abdel-Khalek and Eid 2011; Halama et al. 2010) tried a comparative analysis among the religions and countries, respectively.

The surveys which found no significance between religiousness and various components have been very small in number and most of them with small sample sizes. Also, there have not been any reports yet, which could demonstrate a negative relationship between religiousness and happiness. One research group have showed that higher happiness was obtained either by being highly or by being unremarkably religious, but moderate religiousness made people less happy (Opfinger and Gundlach 2011). Later, the same group concluded that religion can also be substituted by higher income to obtain happiness (Gundlach and Opfinger 2013). But even that factor cannot be considered permanent, as good income can never be guaranteed throughout a lifetime.

As seen in the study, most of the authors have reported a positive association between religion and the factors that control happiness. As mentioned in the introduction, the reasons behind them are the factors like, feeling of being united, being cared mutually, feeling of security, feeling blessed and grateful and the feeling of intrinsic peace. This could lead to an understanding that among majority of the people, religiousness does lead to happiness in life and it is never a negative component in life.

Among the religions, Christianity and Islam were the most rigorously studied ones. Although in Christianity, there has been a variable association between religiosity and happiness. Among Muslims, the association have always been positive till date. Even in the comparative studies conducted by (Abdel-Khalek and Lester 2007, 2013) have shown that Muslims were more religious and happier compared to believers of other religions. Thus this observation is worth a notice and requires further study.

Conclusion and Future Work

A detailed and systematic study on the literature concerning the relationship between religious belief and happiness has been conducted in this paper. The analysis of the data has shown some interesting observations and results. It has been observed that the Asians are the happier people among others. Furthermore, the most religious nations and hence the happiest people were found in the Middle East. Although most of the studies have provided a good understanding on the link between the religious belief and happiness, it is still required by the current and future researchers to conduct further surveys and analyses to solidify the results more clearly. The researchers must try to survey the untested nations to have a wider perception on the human nature. Also, it has become vital to conduct comparative study between nations, cultures and religions to get an understanding of the best combination of characters for a prosperous life.

The study also showed that although various Arab nations have been surveyed, there has been no survey conducted in Oman yet. Thus the authors plan to conduct a survey among the citizens and residents of Oman to find the significance of religious belief on happiness in the country.