“And now you will be sound asleep.” This can be heard often in popular media when hypnosis is demonstrated by lay hypnotists. It has given its name to a procedure and a phenomenology that has little to nothing to do with the nature of hypnosis or sleep. Perhaps because of the popularization in a variety of channels, the application and use of hypnosis in medicine, psychology, and psychiatry has varied considerably over time. There were periods when hypnosis was overvalued, and other times when it was undervalued or ignored, despite empirical evidence for its usefulness with different mental health problems and disorders.

Sleep disturbance is quite common in patients with post-traumatic stress disorder (PTSD), as a symptom of the underlying disorder; as a part of comorbid anxiety, depression, or chronic pain disorder; or as an independent sleep disorder diagnosis [1]. Chronic sleep disturbance from any cause is associated with poorer daytime functioning as well as medical comorbidities and thus critical to address [2]. Insomnia , the most common sleep symptom, is a state of hyperarousal linked to central changes in metabolism and electroencephalographic activity and peripheral mechanisms such as autonomic activation [3, 4]. This physiological state when combined with inadvertent behavioral conditioning (e.g., checking the bedside clock) can become a chronic condition. In patients with PTSD, insomnia can be even more severely chronic given how the associated heightened hypervigilance and nightmares further disrupt sleep [4]. Abnormalities in the brain’s default mode network (DMN) have been implicated in both PTSD, combat trauma (even without PTSD), childhood trauma, and insomnia [5–9]. The DMN is a network of interconnected brain regions which is most active during low-demand tasks such as daydreaming and self-absorbed thinking and when not attending to outside stimuli. One of the under-recognized treatment modalities for insomnia in patients with PTSD is hypnosis. This chapter will review the empirical evidence on the effectiveness of hypnosis for insomnia and PTSD and summarize the neurobiological substrates underlying the hypnotic state, including changes in the DMN [9, 10].

Hypnosis is a state of inner absorption or focused attention which leads to greater suggestibility [11]. Hypnosis is also both a procedure and a phenomenon or outcome of that procedure. Three key factors, or components, with accompanying changes in neural network activity of this state have been identified [12–14]:

There are different theories about how hypnosis works [15]. State theories propose that hypnosis is an altered state of consciousness and that state is associated with a dissociation from higher brain control centers leading to cognitive distortions and increased suggestibility [16]. This latter phenomenon is called trance logic , a voluntary state of acceptance of suggestions without critical judgment or evaluation. Non-state theories propose that the increased suggestibility is a product of a person’s attitudes, expectancies, and motivation and that suggestibility is enhanced by an empathic connection with the hypnotherapist [17]. Regardless of the theoretical underpinnings , hypnosis is a trance state which is associated with different mental and physical processes that are present during a normal alert state [18]. Different depths of trance can be achieved, each associated with different brain wave patterns [19]. Lighter trance states are adequate for relaxation, limb and eyelid catalepsy, and more vivid mental imagery, while deeper trances are associated with catalepsy of all skeletal muscles, ideomotor phenomena (such as automatic writing), age regression, hallucinations, and post-hypnotic effects with amnesia for the event.

The depth of a trance state and individual can achieve is called hypnotizability [20, 21]. Hypnotizability, or hypnotic susceptibility, can best be viewed as a disposition, only manifested under certain conditions, in the same way that water vaporizes when heated and wood is flammable when it is dry and close to a fire. The hypnotic ability may become manifest not only during formal hypnotic induction procedures but also in the context of environmental challenges such as psychological trauma. Although hypnotizability is considered to be variable across individuals, it is stable within individuals, with a test-retest correlation of 60 over periods of 10–25 years, despite training and previous exposure effects [21, 22]. Those who are low on hypnotizability are typically unable to enter a hypnotic state, while those who are high in this trait do so very easily [23]. Hypnotizability appears to peak between the ages of 6 and 10 and then begins a gradual decline as age increases [24]. Approximately 10–15% of the population are highly susceptible to hypnosis, 10–15% are unresponsive, and the remaining 70–80% are moderately susceptible [25]. As a rule of thumb, low hypnotizables often prefer various introspective, analytically oriented psychotherapies. Those who are in the midrange group in hypnotizability respond better to consoltatioin and confrontation from the therapist. Highly hypnotizable individuals benefit most from firm guidelines to enhance their capacity to generate their own decisions and directions.

There is compelling evidence that robust psychological and physiological phenomena underlie hypnosis [26–30]. Changes in neural activity underlie the focused attention, enhanced somatic and emotional control, and lack of self-consciousness that characterizes hypnosis. Changes in relaxation, focus, and absorption, induced by standard hypnotic procedures, are associated with changes in brain activity within different brain areas. There is now growing evidence of the involvement of areas modulating self-related and external sensory input brain networks [29]. One network involves midline brain structures such as the precuneus and the rostral ACC [31], often referred to as the “ default mode network” or DMN (which is thought to involve self-referential processing) [32]. A second network involves lateral frontoparietal regions, associated with attention-demanding tasks and the cognitive processing of sensory input. There are changes in the electrical activity of the brain as evaluated by electroencephalographic (EEG) studies which correlate with trance depth [33]. These EEG changes as well as patterns of eye movement are different than those observed during sleep, suggesting they are different states [34].

In addition to changes in the brain, there are measurable physiological changes in the periphery observed during hypnotic trance states including changes in autonomic (heart rate, respiration, skin conductance), metabolic, and endocrine (glucose and basal metabolism) systems [35, 36]. While these biological processes have been linked to therapeutically induced hypnotic states, they also occur in “spontaneous” hypnotic states such as religious rituals, physical exercise, or getting “lost” in music, a good book, or a mesmerizing movie. Hypnosis used as a therapeutic tool can be referred to as hypnotherapy, though in the literature, the two terms are often used interchangeably.

The use of hypnosis in treating insomnia and sleep disturbances (e.g., night terror) has been described in numerous clinical reports. A meta-analysis by Lam (2015) of randomized controlled trials (RCTs) or quasi-RCTs where hypnosis was the intervention and insomnia the target [37], a total of 502 subjects were included with 6 using hypnotherapy and 7 using hypnotic techniques such as autogenic training or guided imagery. In a meta-analysis across all the studies, hypnosis was associated with significant reduction in sleep latency compared to wait-list control but no difference compared to a heterogeneous mix of conditions including psychotherapy, pharmacological treatment, back massage, and sham (placebo). Nonrandomized studies demonstrated that hypnosis can reduce sleep latency in patients with chronic insomnia [38] and increase slow wave sleep [39] and internet-based self-hypnosis and hypnosis audiotapes [40] can improve sleep over time. A meta-analysis of 59 outcome studies showed short- and longer-term advantages of hypnosis and relaxation training are comparable and, in some studies, greater than drug therapy effects [41].

Prior to using hypnosis, it is advisable to familiarize the patient with “hypnotic-like” experiences, to reinforce debunking of myths about hypnosis, and to ameliorate potential underlying fears about the modality (e.g., loss of control), which will also help build rapport and trust. Quite contrary to giving up control, gaining expertise in self-hypnosis is an opportunity to enhance their control over both mental and physical states and also in gaining control over sleeping problems. In hypnotizability testing there is an element of surprise which is also important. It is this very occasion that can be turned around to demonstrate to the patient how easily he can enhance and expand his own sense of control of himself and his body. These brief quasi informal clinical tests are very useful in evaluating patients for possible hypnotherapy [42]. They not only serve to screen and evaluate, but their very administration can establish a positive psychological set and make later inductions of hypnosis easier. For these reasons, hypnosis may be of greatest benefit in psychotherapy when it is used as a means of teaching skills that empower the patient.

The beneficial effects of hypnosis for insomnia have been most linked to therapeutic targeting of mood (mainly anxiety), thoughts (mainly ruminative worries), and body sensations (physiological arousal). The most common techniques in published literature are relaxation, thought slowing and redirection, and access to preconscious cognitions and emotions [43, 44]. There are specific skills that someone suffering insomnia can learn that will make a positive difference. While relaxation using breathing, muscle relaxation, and guided imagery is the most common skill, targeting the cognitive symptom of rumination or repetitive thinking can also be a powerful tool for insomniacs.

Rumination (repetitive thinking) is the cognitive process of spinning around the same thoughts over and over again. It is considered an enduring style of coping with ongoing problems and stress [45]. Coping responses may distinguish between strategies oriented toward confronting the problem and strategies oriented toward reducing tension by avoiding dealing with the problem directly. Rumination can be thought of as a pattern of avoidance that actually increases anxiety and agitation. Ruminative responses include repeatedly expressing to others how badly one feels, thinking to excess why one feels bad, and catastrophizing the negative effects of feeling bad. By ruminating, the person avoids having to take decisive and timely action, further compounding a personal sense of inadequacy. Rumination leads to more negative interpretations of life events, greater recall of negative autobiographical memories and events, impaired problem-solving, and a reduced willingness to participate in pleasant activities. Various studies provide evidence that ruminative behavior is not only highly associated with depression but serves to increase both the severity and duration of episodes of depression [46]. Thus, rumination is an especially high-priority target at which to aim interventions, hypnotic or otherwise. Rumination generates both somatic and cognitive arousal, both of which can increase insomnia, but the evidence suggests cognitive arousal is the greater problem. Minimal cognitive processing and special effort toward sleep are key hypnotic treatment goals.

In one small parallel arm study included where the 32 participants were combat veterans with PTSD , group hypnosis twice a week for 2 weeks significantly improved symptoms of PTSD as well as insomnia immediately posttreatment and at 1 month follow-up compared to those randomized to zolpidem (10 mg) [47]. Age regression techniques were used to access memories from a time in life when the patient had no sleep disturbances. The past experiences were enhanced and then associated with present feelings using a technique called a cognitive-affective bridge . Ego-strengthening (building sense of self-efficacy and confidence) techniques were also used. For the larger meta-analysis, methodological weaknesses across the studies and a relatively small sample size were cited as limitations. A recent study examined the effectiveness of sleep-directed hypnosis as a complement to cognitive processing therapy (CPT) [48]. When 3-week hypnosis training preceded CPT, significantly greater improvement than the control condition was seen in sleep and depression, but not in PTSD. Hypnosis was effective in improving sleep impairment, but those improvements did not augment gains in PTSD recovery during the trauma-focused intervention. Nightmares are a hallmark symptom of PTSD and a frequently endorsed cause of poor sleep. The use of various behavioral techniques to help patients with nightmares has been discussed in previous chapters. While there is a relative absence of empirical evidence for the efficacy of hypnosis for nightmares, there are several ways that the hypnotic trance can be used to understand the etiology of these re-traumatizing dreams. For example, the content of the nightmares can be more vividly accessed, and related negative emotions can be more readily processed [49]. There is support that dissociation in hypnosis is similar to that which occurs spontaneously during dreams [50]. With the ability of the hypnotist to suggest amnesia for the material that might be re-traumatizing during an alert waking state, hypnosis provides a powerful medium by which to have patient rework traumatic origins of repetitive dream through revivification or dream substitution. There are several case studies supporting the use of hypnosis to improve repetitive nightmares both unrelated to [51] and related to PTSD [52]. These techniques demonstrate that patients can have control first of their hypnotic dreams and then dreams at night. Dream substitution is different from hypnotic abreaction or interpretation of dreams [53].

One way to help PTSD-related insomnia is to treat the PTSD directly. Hypnotic techniques were already used to treat combat neurosis during World War II [54]. There is evidence for the positive effects of hypnosis for both acute and chronic PTSD but few randomized controlled trials [55–58]. In the military, hypnosis has been found to be particularly useful in helping soldiers work through combat traumas [59, 60]. Patients with PTSD, including combat veterans, are more susceptible to dissociation than the general population [61, 62]. Hypnosis in this population can be thought of as controlled dissociation and dissociation in turn as a form of spontaneous self-hypnosis [63]. These patients need to learn to control their flashbacks and learn to regulate their capacity to dissociate. Hypnosis can help with anxiety, reverse traumatic dissociation, facilitate the process of working through traumatic memories, increase ego strength, and promote a sense of competency.

The arousal symptoms of PTSD (flashbacks, dissociative states) can be triggered by olfactory as well as other environmental cues. In a study using hypnosis to associate a particular environmental stimulus with a desired emotional response in a patient with combat-related PTSD, mood and anxiety disorders, and chronic insomnia, there was a nonspecific improvement in all of these disorders [64, 65]. The main hypnotic technique used was an “olfactory bridge ” by which age regression leads the patient to access pleasant memories associated with a sense of control while experiencing a pleasant scent. During repetitive review of the traumatic event during hypnosis, the therapist offers a reframing of the traumatic olfactory memory, replacing it with the pleasant scent. The pleasant scent can be used as an anchor for patients to practice self-hypnosis in the face of anxiety. Other hypnotic techniques to treat trauma as part of PTSD, which are beyond the scope of this chapter, include cognitive restructuring of prior traumatic events [55], ego-part techniques [66], abreactive ego-state therapy [67], “hidden observer” technique to bring closure to the target event [68], and “split screen technique ” by which patients project images of trauma memories on the left side and something they did to protect themselves or their safe place on the right side [69–71]. It remains to be seen what the best strategy is for the dissociative subtype for PTSD as this group of patients frequently engages in self-hypnosis in order to defend against traumatic and stressful experiences and memories [72].

With an understanding of hypnotic principles and techniques, hypnosis can be used to augment the effects of other therapeutic interventions covered in this book (e.g., imagery reversal therapy (IRT), exposure relaxation and reinterpreting (ERRT), nightmare deconstruction and reprocessing (NDR), cognitive processing therapy (CPT), and cognitive behavioral therapy (CBT)) using a multicomponent approach. For example, in classic CBT for insomnia which consists of modifying cognitions interfering with sleep (cognitive restructuring ) and behavioral skills (sleep hygiene behaviors, stimulus control, and sleep restriction techniques), hypnosis can enhance the acceptance and internalization of suggestions in these other domains [73]. Because hypnosis can facilitate relaxation, facilitate imagery rehearsal, and help patients access to preconscious cognitions and emotions, it can be a helpful adjunct [74].

Cognitive hypnotherapy is a treatment where hypnosis combined with CBT is a useful intervention for PTSD [56, 75]. In a study comparing CBT plus hypnosis to CBT alone or supportive therapy, the cognitive hypnotherapy condition was associated with the greatest improvement in reexperiencing symptoms posttreatment but not at 3-year follow-up [76]. The hypothesized mechanism of action for the hypnotic augmentation of CBT in the acute phase of the study was the promotion of self-soothing skills to counter hyperarousal, fortification of positive expectations of the future, and cue-controlled relaxation where an image or verbal cue is paired with a conditioned response to relaxation or some other positive experiences. Even if hypnosis is not used as a therapeutic technique, training and certification to become a medical hypnotist are valuable as it can provide therapeutic value in understanding the language of change and patient receptivity to suggestion. The use of permissive language and techniques such as pacing and leading can all enhance treatment recommendations [77].

Formal hypnosis involves a series of sequential steps: induction, deepening , hypnotic suggestions , re-orienting (arousal, awakening), and debriefing (processing and reflecting) when the patient is fully alert. An example of an induction is as follows:

Traditional induction is often done with the eyes closed using suggestions of drowsiness or relaxation. One technique that has shown positive effects for veterans with PTSD is using an alert induction technique [78], where eyes are open and suggestion is for activity and alertness instead of relaxation. “You are becoming increasingly more alert and attentive” (while the patient is doing something active such as moving arms or hands rigorously and with open eyes staring at a stationary spot). Examples of deepening techniques include: