IRT is indicated for the treatment of chronic nightmares, including trauma-related nightmares . In individuals with PTSD, IRT is typically considered an adjunctive intervention targeting nightmare symptoms once psychotherapeutic and/or pharmacologic treatments for PTSD have been optimized. Because imagery techniques can trigger flashbacks, use of IRT may be contraindicated in individuals with severe PTSD symptoms [29]. Other contraindications include individuals with cognitive deficits (e.g., brain injury, inability to access the visual imagery system), severe mental illness, and high levels of anxiety, stress, or avoidance [15, 17].

Certain challenges in implementing IRT can be anticipated. Because avoidance is a common response to anxiety-provoking nightmares, engaging the patient in the treatment process may be difficult. Indeed, investigators have reported dropout rates exceeding 40% in some samples, with many individuals dropping out before or very early in treatment [2, 30–33]. Patients may be skeptical about their ability to change nightmares or reluctant to engage in a psychological intervention. They may attend return visits having not revised their nightmare or practiced the imagery technique. Some individuals are resistant to changing the nightmare, particularly if it is replicative of a trauma memory, because such a change does not represent the reality of the event. We have found that such patients often respond positively to our “movie mogul” analogy wherein they are encouraged to pretend they are a movie director, producer, screenwriter, and starring actor of their new story line. This perspective may enhance the creative flexibility to create a new story. Overall, these challenges bespeak the importance of the therapeutic relationship for developing rapport and fostering treatment credibility.

Adverse effects related to IRT have been described [20, 24]. Patients engaging in imagery rehearsal may experience negative, distracting, or intrusive images. Teaching skills to help patients normalize and manage such experiences typically are incorporated into the IRT protocol [28]. Additionally, IRT may exacerbate PTSD symptoms in some cases [2, 24]. Clinically, we sometimes experience this phenomenon with patients who do not adhere to treatment recommendations and instead focus on their distressing nightmare while failing to complete the rescripting and rehearsal steps .

Various treatment modifications have emerged as IRT has grown. These variations include elements of the technique itself, the application of IRT to special populations, and alterations in treatment duration, delivery, and format. IRT has also been combined with other therapies in attempts to maximize therapeutic success.

Among psychotherapy interventions for nightmares, IRT has received the most empirical support and has the highest recommendations for nightmare treatment based on substantial clinical data and strength of clinical consensus [24, 54]. Several meta-analytic reviews of IRT over the past few years have substantiated these clinical recommendations for samples that have included civilian and veteran populations [31, 33, 37]. IRT reduces nightmare frequency, improves sleep quality, and alleviates PTSD symptoms and other measures of psychological distress, with treatment effect sizes in the moderate to large range [30, 31, 33, 37, 55]. Furthermore, the therapeutic benefits of IRT are maintained long term [2, 31, 56–58, 59], with one study of civilian nightmare sufferers showing sustained treatment gains at 2.5 years follow-up [57]. Whether individuals with a PTSD diagnosis benefit from IRT equally to those without a PTSD diagnosis is difficult to discern due to variations in sample reporting [30], although one small uncontrolled study suggests that individuals with PTSD may have a muted response to IRT treatment [60]. However, a recent randomized controlled study compared IRT to treatment as usual in an outpatient psychiatric population with nightmares and a diverse array of psychiatric disorders (including PTSD) [55]. The patients receiving IRT showed a significant reduction in nightmare symptoms, suggesting that individuals with psychopathology and comorbid nightmares can benefit from IRT.

Given the high rates of PTSD and sleep disturbances in military service members, there is growing interest in the application of IRT to military populations. Meta-analytic reviews suggest that military/veteran populations benefit as much as civilian populations in their posttreatment reductions in nightmare frequency and PTSD symptoms [31, 37]. Sleep quality outcomes are less clear, with one meta-analytic review reporting that civilian participants showed greater improvement in sleep quality compared to veteran participants [31], a finding that was not replicated in a second review [37]. Several investigators have recognized a potential benefit of trauma-focused PTSD treatment in preparing veterans for a successful therapeutic engagement in IRT [21, 23, 56, 61], although conditions determining the optimal sequencing of treatments remain to be elucidated. Difficulties with IRT treatment engagement and adherence in veterans have been observed [21, 23, 61] and will be an important focus of future research .

IRT is an effective short-term intervention that is both inexpensive and flexible. It is an attractive alternative for individuals who may be seeking non-pharmacologic approaches for treating nightmares. Pharmacologic treatments such as prazosin provide symptomatic relief of nightmares in combat veterans , the benefits of which may be lost after medication withdrawal [62]. In contrast, IRT provides therapeutic benefit long after the treatment is concluded, in a manner that is empowering to the patient.

Clearly, additional randomized controlled trials with larger veteran samples are needed to further clarify the benefits of IRT. The literature to date is limited not only by a paucity of randomized controlled study designs but also by variations in IRT treatment approaches and the use of different outcome measures to assess nightmares, insomnia, and PTSD. Developing a standardized treatment approach along with measures of treatment integrity and fidelity is needed to advance understanding [33]. In addition to measuring primary outcomes , investigators should explore secondary outcomes such as depression and anxiety. Dismantling studies are needed to reveal the therapeutic mechanisms or active ingredients of IRT. Further, the optimal dose of IRT (e.g., number and length of sessions) remains to be determined, along with the relative benefits of group versus individual formats. Combining IRT with other treatments for PTSD and/or insomnia shows much promise, although more information is needed on how to best apply these approaches. The optimal sequencing of IRT relative to trauma-focused therapy for PTSD as well as any additive benefit from prior trauma processing is unclear.

Additionally, studies are needed to clarify patient variables that influence IRT success in veterans . Such variables include comorbid psychiatric or medical disorders , nightmare content or type (e.g., recurrent, trauma related, replicative), PTSD severity, and era of military service. As others have noted, younger veterans returning from current conflicts and reassimilating into civilian life experience unique stressors (e.g., traumatic brain injury, threat of redeployment) and life situations (e.g., inflexible work or school schedules) that may impact their ability to engage in treatment [47, 51]. IRT may need to be tailored to suit the needs of these individuals. An important question with veterans newly exposed to trauma is whether early intervention with IRT could prevent or mitigate future PTSD symptoms.