Treating post-traumatic stress disorder-related dreams: what are the options?

Keywords::

• nightmare
• post-traumatic stress disorder
• trauma
• trauma-related dream
• treatment

Trauma-related dreams are a highly prevalent and distressing symptom of post-traumatic stress disorder (PTSD). They are classified as one of the intrusive or re-experiencing symptoms along with daytime memory intrusions, dissociative flashbacks and distress, when confronted by reminders. International treatment guidelines consistently recommend trauma-focused cognitive behavior therapy as the first-line treatment for PTSD, and selective serotonin reuptake inhibitors as the preferred pharmacological treatment [1]. Where effective, these treatments that target the full range of PTSD symptoms represent the most parsimonious approach. Unfortunately, however, the post-traumatic dreams of PTSD can be resistant to standard psychological and pharmacological treatments for the disorder [2,3]; and in recent years, there has been increasing attention paid to treatments that target the symptom specifically.

On the basis of evidence to date, the recommended first-line psychological treatment for post-traumatic dreams of PTSD is imagery rehearsal therapy, and the recommended first-line pharmacological treatment is prazosin [4]. It is interesting to note that neither of these treatments was originally intended for PTSD. Imagery rehearsal is a cognitive behavioral intervention for recurrent idiopathic nightmares that involves changing the storyline of a nightmare and rehearsing the new dream images [5]. Prazosin is a treatment for hypertension, with its positive impact on the post-traumatic dreams of PTSD discovered secondarily [6]. The reason for the effectiveness of prazosin, with its impact on CNS adrenergic activity, is self-evident. However, the success of imagery rehearsal therapy raises a fundamental question about the nature of post-traumatic dreams. Why should post-traumatic dreams, an intrusive symptom of psychological disorder, be effectively treated with an intervention intended for normal dreams?

In consideration of this issue, it is important to remember that post-traumatic dreams are not specific to PTSD; they are also common in people exposed to trauma who do not develop PTSD [7]. However, far from being considered pathological, these non-PTSD trauma-related dreams are believed to serve an adaptive psychological function in promoting the emotional and cognitive integration of traumatic experience [8]. The two types of dream (PTSD and non-PTSD trauma-related dreams) have long been understood as categorically different phenomena: a pathological symptom of disorder versus a dream [8,9]. However, there is no empirical evidence for this [10]; and the success of treatments intended for normal dreams, when applied to the post-traumatic dreams of PTSD, challenges the assumption of a categorical distinction.

Although current pharmacological and psychological approaches to the treatment of post-traumatic dreams are promising, both have their limitations. Prazosin, for its part, has been found to provide symptomatic relief of nightmares, but the positive effects do not persist when the treatment is ceased. With respect to imagery rehearsal, a number of studies have shown promising results overall; but there is evidence that the intervention is effective for some but not others. For example, a number of small, uncontrolled trials report that the treatment was effective for 50–60%, but not all participants [11–13]. This variability highlights the possibility that post-traumatic nightmares of PTSD are not a single phenomenon, and may respond differentially to imagery rehearsal treatment depending upon the extent to which they are similar in their phenomenology to PTSD intrusions or normal dreams. Hence, improved understanding of the phenomenology of post-traumatic dreams is needed to guide future developments in psychological treatment.

To differentiate between phenomenological ‘types’ of post-traumatic dream in PTSD, the assessment would need to go beyond current B2 diagnostic criterion, which specifies “recurrent, distressing dreams of the event” [14], or even the proposed tightening of criterion in the Fifth Edition of Diagnostic and Statistical Manual of Mental Disorders to “recurrent, distressing dreams in which the content and/or affect of the dream is related to the event” [101]. Determining the extent to which dreams are more like intrusions or normal dreams is not as simple as looking to their content and affect. Researchers have described a range of dreams associated with PTSD, which vary in the extent to which the traumatic event is replicated [15,16]; and Phelps et al. found no difference between replay, mixed and nonreplay dreams in PTSD severity [17]. Rather, the assessment would need to incorporate phenomenological features of daytime PTSD intrusions, such as sensory fragments of traumatic experience, strong physical sensations and original emotions [18], as well as features of normal dreams, such as their elaborate storyline, distorted or bizarre elements and strong visual imagery [19].

However, it is also possible that all dreams following trauma begin as the same phenomenon, but their course of chronic repetition (associated with PTSD) or resolution (associated with recovery) is determined by other factors [10]. The most obvious potential mediating factor is the sleep disturbance associated with PTSD. Sleep is a necessary condition for the proposed adaptive function of dreams in facilitating the cognitive and emotional integration of traumatic experience. Sleep disruption may prevent this adaptive function, and thus contribute to nightmares becoming stuck in a pattern of chronic repetition.

A second possibility is that the course of post-traumatic dreams is determined by the individual’s response to the experience of the dream, with nightmare-related fear and avoidance contributing to the maintenance of the phenomenon. This is consistent with Steil and Ehlers contention that negative appraisals of intrusive symptoms exacerbate distress, which, in turn, leads to cognitive and behavioral avoidance and the maintenance of symptoms [20]. Similarly, within the dream treatment literature, the power that the nightmare holds over the dreamer is considered critical in the maintenance of the nightmare and successful interventions involve ‘facing and conquering’ the feared nightmare [21].

Going forward, options for the treatment of post-traumatic dreams in PTSD should be guided by more detailed assessment of the precise phenomenology of the dream, associated sleep disturbance and the individual’s response, in order to target potential maintaining factors. First, with respect to phenomenology, dreams that are like other intrusions of PTSD, with phenomenology shaped by the psychopathology of PTSD, may respond to established PTSD treatment. On the other hand, dreams that are more influenced by normal dreaming processes and share features of normal dreams, may be better treated with interventions such as imagery rehearsal therapy. Second, with respect to associated sleep disturbance, there is growing evidence for the efficacy of cognitive behavioral therapy for insomnia in PTSD [22], with the need to address particular features of trauma-related insomnia, such as the avoidance of sleep for fear of nightmares, or loss of vigilance, increasingly recognized [23]. Third, cognitive behavioral therapy should target such maladaptive appraisals and promote a ‘face and conquer’ orientation, where the individual’s response to post-traumatic dreams serves to foster fear and avoidance. Of note, this change in stance towards the nightmare is at the core of the imagery rehearsal intervention [5].

As we come to understand more about phenomenological differences between post-traumatic dreams of PTSD and normal dreams, a more directive approach to imagery rehearsal, which deliberately changes dreams in ways that make them more ‘dream like’, and therefore, more amenable to adaptive emotional processing functions, may emerge. There are a number of possibilities in this regard. First, imagery rehearsal aims to promote sleep continuity by reducing the distress experienced in the dream. There is potential to address this more explicitly by building in, not just a positive, but a relaxing end to the dream. Second, imagery rehearsal could be used to rescript the post-traumatic dream in ways that make it more like a normal dream with bizarre, distorted and unrealistic elements. Third, any loose connections between the content of the dream and previous (nontraumatic) experience could be exploited. For example, a combat veteran who has a recurrent replay dream of an ambush on operation, made a connection between hearing the sound of movement in the bushes prior to the ambush, with playing hide and seek as a child. Through imagery rehearsal, the storyline of the dream could be changed to ‘switch track’ from the traumatic experience to the memory of a previous nontraumatic experience, at the point of hearing a sound in the bushes.

The relative success of targeted treatments for PTSD-related sleep disturbance supports the notion that these are core features of the disorder, rather than a secondary symptom [2]. To the extent that the experience of post-traumatic dreams of PTSD, and the individual’s reaction to them, contributes to the perpetuation of the disorder, further developments in effective treatments have the potential to lead to substantially improved outcomes for people with PTSD.

Finacial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.