paid to sleep disturbances, patients often continue to suffer from insomnia and nightmares, which, according to these models, may perpetuate PTSD. The possible interactions of sleep disturbances and PTSD are compatible with several models of the relation of stress, sleep, and PTSD, each of which may hold for different patients:
- Sleep abnormalities, regardless of cause, predispose one to the development of PTSD after an acute stressor;
- Sleep abnormalities resulting from acute stressors may cause PTSD— i.e., sleep disturbances mediate the relationship between acute stress and PTSD; and
- Sleep disturbances and other PTSD symptoms develop in response to the acute stressor, and sleep disturbances may be resistant to standard PTSD therapies that do not explicitly deal with them. If any of these three relationships hold, it is clear that treatments must explicitly focus on sleep disturbances to obtain optimal results with PTSD.
FINE-TUNING UNDERSTANDING
Recent studies have indicated that PTSD is often associated with sleep-disordered breathing. Two explanations for this association have been advanced, both of which are plausible and may cooccur. As has been described, sleep, including REM sleep, is broken up in patients with PTSD. It has been shown in experimental settings that such sleep fragmentation is associated with an increased tendency for airway collapse. While such airway collapses may not be of magnitude to cause sleep apnea (a temporary suspension of breathing occurring repeatedly during sleep), with its easily observable arousals, gasping for breath, snoring, etc., they can cause hypopneas (abnormally slow, shallow breathing), which trigger microarousals that serve to restore sufficient airflow— i.e., hypopneas lead to further sleep fragmentation. This is known as upper airway resistance syndrome (UARS). These apneas or hypopneas have been shown to lead to nightmares or at least
to impart negative emotional tones to the dreams associated with them. Thus, it is clear how a vicious cycle could result, leading to both nightmares and fragmented sleep.
Disruptions of other phases of sleep lead to lack of restorative sleep (sleep that leaves a person feeling that he or she has had a good night's rest). This decrease is often associated with daytime sleepiness and/or a lack of energy. Other signs of sleepdisordered breathing include: morning headaches, dry mouth, nocturia (waking up to urinate), and cognitiveaffective disturbances, which include depression, anxiety, attentional problems, and memory disturbances, among others. Since upper airway resistance syndrome may require state-of-the-art technology for its detection, sleep-disordered breathing often remains undetected and hence ignored. Aside from the technical difficulties associated with the detection of subtle forms of sleep-disordered breathing, their neglect in part results from the tendency of both doctors and patients to focus most on the psychological aspects of PTSD as the explanation of symptoms, including sleep disturbances.
It has been proposed that in at least some cases, sleep problems that persist after psychological and/or pharmacological treatments result from sleep-disordered breathing continuing. Indeed, it has been shown that in some cases, treating PTSD by continuous positive airway pressure (CPAP) alone, which is the gold-standard treatment for sleepdisordered breathing, and without any psychological intervention, not only alleviates sleep problems but can also cause a dramatic relief from other PTSD symptoms, underscoring the potential causal or mediating role of sleep problems, including sleep-disordered breathing in the genesis of PTSD. Since many patients with PTSD find that continuous positive airway pressure may produce claustrophobia and anxiety, conservative approaches such as instruction to sleep on the side instead of the back, attention to nasal hygiene, or the use of nasal dilator strips may be used first. The latter techniques clear the nasal
passages, thus decreasing airway resistance and, hence, mini-collapses. Periodic limb movements in sleep, which disrupt and fragment sleep are also increased in patients with PTSD, probably due to increased noradrenergic tone.
PSYCHOLOGICAL TREATMENTS
In addition to medication and treatments for underlying sleep-disordered breathing, there are a variety of psychological approaches to the treatment of sleep disturbances. One of these, imagery rehearsal therapy (IRT), focuses on the symptom of disturbing nightmares. In this treatment, patients are taught techniques of imagery and how to apply these to their nightmares. Two types of instructions have been employed that are equally effective.
In one of these, patients are asked to remember a nightmare, write it down, and then change the ending in any way they deem helpful and rehearse the new "dream." This is often done in group sessions. This technique has been shown to have ongoing positive effects on the number of nightmares per week and the number of nights without nightmares. Furthermore, insomnia is often improved because of the decrease in sleep disturbances resulting from nightmares and a decrease in protective behaviors adopted in attempts to ward off nightmares. (These protective behaviors include: delaying bed time, getting out of bed when waking rather than trying to get back to sleep, sleeping with lights on, substance abuse, and others). PTSD symptoms often decrease as sleep improves. Some patients find that imagery rehearsal is stressful and may increase fears. These negative effects may be decreased by first teaching patients how to employ pleasant imagery and having them start with less fear-inducing dreams (e.g., those not dealing explicitly with the traumatic events and limiting imagery rehearsal therapy to one dream per week).
A second form of psychotherapy dealing with sleep issues is Sleep Dynamic Therapy® (SDT), which includes a multitherapeutic focus on sleep issues in