Post-traumatic nightmares (PTNs) are common and persistent…

Post-traumatic stress disorder (PTSD) develops in approximately 25–30% of people of any age who experience a stressful event or situation of an exceptionally catastrophic or threatening nature [1]. PTSD can stem from experiencing or witnessing single, multiple or repeated traumatic events such as abuse (including childhood or domestic), accidents of a serious nature, assault (physical or sexual), conflict and war, torture, trauma related to health problems or childbirth experiences (e.g. admission to intensive care, neonatal death), and work-related trauma exposure (including remote exposure) [1].

PTSD can present with a wide range of symptoms [1], including the four symptom clusters [2] of avoidance (of activities, people, places and situations associated with trauma-related stimuli, or of general social contact), emotional numbing, hyperarousal (e.g. anger, hypervigilance, irritability), and re-experiencing or intrusive symptoms (e.g. unwanted thoughts, flashbacks, nightmares) [1,2,3]. Among these, post-traumatic nightmares (PTNs) have a prevalence as high as 88% [3] and can persist throughout life even if the other symptoms of PTSD resolve [4]. This persistence has led to the conceptualisation of PTNs as an independent sleep disorder [3].

…and targeted treatment is important

PTNs worsen the prognosis of PTSD, possibly by disrupting the normal processing of traumatic memories during sleep [3]. PTNs can also lead to other sleep disturbances such as insomnia or sleep avoidance that may, in turn, adversely affect daytime PTSD symptoms. PTNs are associated with functional impairment, poor health outcomes, significant distress and a decreased quality of life. In addition, nightmares are an independent risk factor for suicide. Persistent chronic nightmares, in particular, are associated not only with repeated suicide attempts but also with non-suicidal self-injury [3]. Considering this and the resistant nature of PTNs to general PTSD treatment, targeted treatment of PTNs is important [2]. This article summarizes existing and promising treatment options for PTNs, as reviewed by Geldenhuys et al. [3] and Martin et al. [2].

Post-traumatic stress disorder treatments don’t always treat PTNs…

PTSD can be treated with psychological therapies, pharmacotherapy, or both [2]. Most guidelines recommend cognitive behavioural therapy (CBT), trauma-focussed CBT, or eye movement desensitisation and reprocessing (EMDR) specifically, as first-line psychological therapy [2]. CBT is a general term that encompasses several different short-term and goal-oriented therapies that involve psychotherapeutic and behavioural techniques striving to modify a person’s dysfunctional behaviours, emotions and thoughts [4]. CBT includes cognitive processing therapy, image rehearsal therapy (IRT) and prolonged exposure therapy [2]. Psychotherapy is recommended over pharmacotherapy for first-line treatment of PTSD in approximately one third of guidelines. SSRIs (e.g. fluoxetine, sertraline, paroxetine) or venlafaxine are first-line pharmacological options [2].

Nightmares, which are one of the most critical symptoms of PTSD to treat, are often overlooked as a secondary symptom of PTSD [2]. Most guidelines for PTSD do not mention the targeted treatment of nightmares as a symptom of PTSD. Those that do recommend the targeted treatment of nightmares vary in the choice and strength of their recommendations [2]. Effective treatment of nightmares is important and often leads to improvement of other PTSD symptoms [3].

Trauma-focussed CBT additionally includes psychotherapies like EMDR [2]. There is good evidence for IRT and some evidence for sleep-specific CBT in the treatment of nightmares, while the positive efficacy of EMDR in PTNs has not been investigated extensively in randomized controlled trials [3]. In terms of pharmacological therapies, sertraline can lead to significant reductions in nightmares, and fluoxetine is associated with a non-significant improvement in nightmares. Paroxetine is not a treatment option for PTNs because it is associated with nightmare induction, and evidence does not support the use of venlafaxine [3].

Although non-pharmacological therapies are preferred…

Non-pharmacological therapies are currently the preferred treatment for PTNs [3]. The American Academy of Sleep Medicine (AASM) recommends IRT for the treatment of PTN [4], and the American Psychiatric Association suggests it as a treatment option [2, 5]. Behavioural treatment of PTNs is based on the concept that nightmares are acquired/learned behaviours that can be modified with target intervention [6]. In IRT, it is thought that daytime rehearsal of altered dream scripts (i.e. script of recurring nightmare modified with a new scenario and different ending) can alter the conditioned relationship between sleep and nightmares [6]. The AASM also states that the following behavioural and psychological treatment options may be used for the treatment of PTSD-associated nightmares: CBT, CBT for insomnia, exposure, relaxation and rescripting therapy (ERRT; an IRT variant), and EMDR [4].

…patients may want pharmacological agents…

Patients may prefer pharmacological agents over non-pharmacological therapies because they are possibly easier to access than non-pharmacological therapies [3]. Although there is no pharmacological agent that has been specifically approved for the treatment of PTNs, there are established agents that have been used to treat PTNs (Table 1) [3].

Table 1 Examples of established agents and evidence for the treatment of post-traumatic nightmares in adults, as reviewed by Geldenhuys et al. [3]
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The efficacy of prazosin in the treatment of PTSD-associated nightmares has been demonstrated in at least ten studies [4]. However, results from the recent PACT trial (Table 1) has led to the downgrading of the recommendation for use of prazosin to treat nightmare disorder by the AASM. The AASM task force noted that > 75% of patients in either group in that trial were receiving maintenance antidepressant medications, and that a possible interaction between prazosin and antidepressant medications needs to be clarified [4]. Also, whether inconsistencies in findings could be related to the type of trauma population (e.g. civilian vs military [3], with or without psychosocial instability [2]) remains to be determined.

Despite the downgrade because of the contradictory trial, the AASM retains prazosin as an option for treatment and acknowledges that prazosin may remain the first choice for pharmacological therapy because it is apparent to clinicians that many patients have a very good response to prazosin [4]. In addition, subsequent meta-analyses (Table 1) have shown strong evidence for the efficacy of prazosin in reducing PTNs [3]. Although the efficacy of prazosin for the treatment of PTNs has been questioned, it remains the agent with the strongest evidence base for reducing PTNs [3]. The Anxiety Disorders Association of Canada (ADAC) lists prazosin as having level I evidence for reducing trauma nightmares in patients with PTSD [7]. Other guidelines discuss the potential for prazosin use but recommend it as third-line therapy or include no specific recommendation on its use [2].

Although other pharmacological options can be considered for the management of PTNs (Table 1), data supporting their use are low-grade and sparse [3]. Doxazosin may be considered an alternative to prazosin pending further research. Clonidine has some evidence supporting its use, but with caution in patients with cardiac conduction disturbances, ischaemic heart disease and renal impairment. Evidence supporting the use of antidepressant monotherapy (e.g. selective serotonin reuptake inhibitors) is limited. Data for tricyclic antidepressants and mirtazapine (both mostly used as add-on therapy) are from low-evidence studies. Trazodone has some evidence of efficacy but may be poorly tolerated. While single prospective trials support the use of the atypical antipsychotics risperidone, olanzapine and quetiapine as add-on therapy, quetiapine is poorly tolerated. The evidence base for the antihistamine cyproheptadine, which has been investigated as add-on therapy, remains fairly weak. Limited evidence from non-randomized studies support add-on therapy with the anti-seizure medications gabapentin and topiramate. Of note, evidence does not support the use of β-blockers, benzodiazepines (particularly clonazepam), phenelzine, sedative hypnotics or venlafaxine for the treatment of PTNs [3].

Table 2 Examples of agents with potential but requiring further investigation for the treatment of post-traumatic nightmares in adults, as reviewed by Geldenhuys et al. [3]
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…and the decision regarding treatment should be shared

Upon determination to treat the nightmares, the decision regarding optimal therapeutic intervention (behavioural or pharmacological) should be shared between the patient and clinical provider [6]. The severity of the nightmares, accessibility of the treatment modality (e.g. some may not be readily available in rural areas), cost of treatment, duration of treatment and patient preference should all be taken into consideration [2, 6].

Additional agents require further investigation

Pharmacological agents that are promising but lack more supportive data are presented in Table 2. The use of ramelteon, cannabinoids, ketamine, 3,4-methylenedioxymethamphetamine and trihexyphenidyl are not yet advised in routine management [3]. Although data are sparse for these agents and their use is controversial, they should not be overlooked. Further evaluation is needed to determine the efficacy of these agents in the treatment of a range of PTSD symptoms, including PTNs [3].

Take home messages

  • PTNs are one of the most critical symptoms of PTSD requiring treatment

  • Targeted treatment of PTNs is important because they are resistant to general PTSD treatment

  • Recommend non-pharmacological therapies first, IRT in particular

  • Consider prazosin if pharmacological therapy is warranted

  • Additional treatments are available, though of low-grade or limited data, and novel agents are being explored