Nightmares and PTSD: Research Review

Tina Crenshaw, PhD, MLS, MSEd

Nightmares are dreams that are threatening and frightening. Nearly everyone has had an occasional nightmare, but for trauma survivors, nightmares can be a common source of distress. Nightmares are one of the 17 symptoms of PTSD (1). Along with flashbacks and intrusive thoughts or memories, nightmares are one of the ways in which a trauma survivor may re-experience or relive the traumatic experience for months or years following the event.

How common are nightmares following trauma?

In the general population, few people complain of nightmares; estimates range from 3-7% (2-4) of the population. Those who have gone through trauma, regardless of its specific type, are more likely to have distressing nightmares after the event (4-6). Trauma survivors who develop PTSD are even more likely to complain of nightmares. For example, data from the National Vietnam Veterans Readjustment Study showed that nightmares occurred sometimes or more frequently in only 3% of civilian subjects. In contrast, 52% of combat Veterans with PTSD reported that level of nightmares (4). In other research using normative data, 71% of those with PTSD endorsed nightmares (7). That figure jumped to 96% of those with PTSD and a comorbid diagnosis of panic disorder. Not only are nightmares seen in a high percentage of people with PTSD, those who have nightmares may experience them quite frequently. In one study, participants with PTSD had nightmares several times a week (8).

What are the characteristics of posttraumatic nightmares?

The content of posttraumatic nightmares often involves the original threatening or horrifying circumstances of the traumatic event. For example, someone who went through Hurricane Katrina may have dreams about high winds or floods, trying to escape the waters, or being in the Superdome or some place that did not feel safe. A survivor of a hold-up might experience nightmares about the attacker or about being held at gunpoint.

Not all nightmares that occur following trauma are a direct replay of the trauma. Despite varying methodology which makes comparisons difficult, the results of several studies suggest that roughly half of those who experience posttraumatic nightmares may have dreams that exactly replicate the traumatic event (2, 8). Individuals diagnosed with PTSD are more likely to have nightmares that are exact replays of the traumatic event than are trauma survivors without PTSD (8).

Lab research has shown that posttraumatic nightmares are different in their physical characteristics from those experienced in the general population. They may occur earlier in the night and during different stages of sleep, and they are more likely to be accompanied by body movements (9).

Nightmares and cultural differences

Posttraumatic nightmares may be viewed differently in different cultures (10). For example, in some cultures nightmares are interpreted as representing physical and spiritual vulnerability (11). In other cultures, it is believed that the dreams may contain messages from spirits or premonitions about the future (12). These interpretations may lead nightmare sufferers to perform specific rituals and practices in an effort to protect themselves. Clinicians should be aware of cultural differences in nightmare interpretation, and possible practices in response to posttraumatic nightmares.

Are there any effective treatments for posttraumatic nightmares?

Nightmare symptoms often remit with standard PTSD treatment. If nightmares persist, specific behavioral and psychopharmacological treatments have been found to reduce their frequency.

Behavioral treatment

One promising treatment is known as Imagery Rehearsal Therapy (IRT). In IRT, the clients, while awake, change the endings of their remembered nightmares, so that the ending is no longer upsetting. Clients then imaginally rehearse the new, nonthreatening images associated with the changed dream. In two randomized controlled trials, an IRT-treated group showed improvement in nightmare frequency and PTSD symptoms relative to controls (13-14).

In addition to psychotherapy approaches, treatment for sleep-disordered breathing may also be useful in managing posttraumatic nightmares. High levels of sleep-disordered breathing have been seen in trauma survivors (15) and treatment of sleep apnea with continuous positive airway pressure (CPAP) has been shown to eliminate violent, anxious dreams (16).

Psychopharmacological Treatment

Little information is available on medications for posttraumatic nightmares. The research to date has largely been uncontrolled, with small samples, heterogenous participants, and contradictory results. The most promising research is with prazosin. Two placebo-controlled trials have found positive results for prazosin in reducing nightmare symptoms (17-18), and another controlled trial of prazosin is under way (19). Other medications that show promise, but with an even more limited evidence base, include nefazodone, mirtazepine, and olanzapine (20-21).

References

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15. Krakow, B., Haynes, P.L., Warner, T.D., Santana, E., Melendrez, D, Johnston, L., ...Shafer, L. (2004). Nightmares, insomnia, and sleep-disordered breathing in fire evacuees seeking treatment for posttraumatic sleep disturbance. Journal of Traumatic Stress, 17(6), 257-268.
16. Carrasco, E., Santamaria, J., Iranzo, A., Pintor, L., De Pablo, J., Solanas, A., ...Boget, T. (2006). Changes in dreaming induced by CPAP in severe obstructive sleep apnea syndrome patients. Journal of Sleep Research, 15(4), 430-6.
17. Raskind, M.A., Peskind,E.R., Hoff, D.J., Hart, K.L., Holmes, H.A., Warren, D., ... McFall, M.E. (2007). A parallel group placebo controlled study of prazosin for trauma nightmares and sleep disturbance in combat veterans with post-traumatic stress disorder. Biological Psychiatry. 61(8), 928-34.
18. Raskind, M.A., Peskind, E.R., Kanter, E.D., Petrie, E.C., Radant, A., Thompson, C.E., ...McFall, M.M. (2003). Reduction of nightmares and other PTSD symptoms in combat veterans by prazosin: a placebo-controlled study. American Journal of Psychiatry, 160(2), 371-3.
19. Seed money from Seattle VA-affiliated foundation leads to PTSD breakthrough. (November 9, 2009). Veterans Health Administration, Research & Development. Accessed at: http://www.research.va.gov/news/research_highlights/ptsd-110909.cfm.
20. van Liempt, S., Vermetten, E., Geuze, E., & Westenberg, H.G.M. (2006). Pharmacotherapy for disordered sleep in post-traumatic stress disorder: A systematic review. International Clinical Psychopharmacology, 21(2), 193-202.
21. Friedman, M.J., Davidson, J.R.T., & Stein, D. J. (2009). Psychopharmacotherapy for adults. In E.B. Foa, T.M. Keane, M.J. Friedman, & J.A. Cohen (Eds.), Effective Treatments for PTSD (2nd ed., 245-268). New York, NY: Guilford.