**1. Introduction**

#### **1.1. PTSD and nightmares**

Nightmares (NM) are one of the intrusion symptom clusters of post-traumatic stress disorder (PTSD) in the fifth edition *Diagnostic and Statistical Manual of Mental Disorders* (DSM-5) [1]. The prevalence of frequent NM is 70% in individuals with PTSD compared to only 2–5% in the general population [2]. Post-traumatic nightmares (PTNMs) are different from "normal" dreams as they are recurrent frightening dreams of past traumatic events [3]. Their content may vary from an exact replay to only some components of the trauma, such as changes in time and place [3]. Another distinction is their role in PTSD. In the general population, sleep loss impacts daily functioning due to fatigue and cognitive difficulties [4], leading to poor quality of life [5]. However, in the particular PTSD context, the presence of NM seems to be related to PTSD prevalence and severity [6], and therefore, to contribute to the development of PTSD. They could even contribute to PTSD symptom maintenance [7].

PTSD used to be considered as an anxiety disorder in the fourth edition revised *Diagnostic and Statistical Manual of Mental Disorders* (DSM-IV-TR) [8]. Now, it is part of the trauma- and stressor-related disorders in the DSM-5 [1]. Several meta-analyses, systematic reviews, and guidelines underline that general trauma-focused cognitive and behavioral treatments (CBTs) (through exposure and cognitive restructuring) are superior, or equivalent, to other types of psychological treatments, such as eye movement desensitization and reprocessing (EMDR), psychodynamic psychotherapies, or supportive techniques (e.g., [9]). They also emphasize the efficacy of selective serotonin reuptake inhibitors (SSRIs) as a pharmacological treatment [10]. However, studies also reveal that CBTs and SSRIs do not effectively resolve all PTSD symptoms in individuals who no longer meet PTSD diagnosis criteria. In fact, NMs were found to be treatment resistant, and residual insomnia was also reported [11, 12].

#### **1.2. Emergence of treatments directly targeting nightmares**

One approach is to conceptualize NMs in two steps after a traumatic event. First, right after the trauma, NMs would be considered as trauma-induced and would be a PTSD symptom. Later, at a second stage, they would become a learned behavior distinct from PTSD symptoms. The idea is that the person, by fearing and avoiding NM content, cannot process the information related to the event and cannot incorporate it [13]. As these NMs disrupt sleep, it can be difficult for the victims to return to sleep and they may adopt unsuitable sleep hygiene, which could lead to insomnia [14]. Therefore, new psychological and pharmacological treatments are emerging and tested to directly reduce NMs.

Recently, the Standards of Practice Committee (SPC) of the American Academy of Sleep Medicine (AASM) commissioned a task force to assess the literature on the treatment of NM disorder in general. They presented their recommendations in a Best practice guide about pharmacotherapies and CBTs for NM for adults [15, 16]. Their classification was based on study designs from "level 1" (high-quality randomized clinical trials with narrow confidence intervals) to "level 4" (case series or poor case-control studies or poor cohort studies or case reports). Their suggestions were made according to a level of recommendation from "level A" (treatment recommended—level 1 or 2) to "level C" (treatments that may be considered—lever 3 or 4). Their recommendations concerned both psychological and pharmacological treatments.

Regarding the medications conclusions, Prazosin was given an "A level recommendation" compared to antidepressants, anxiolytics, anticonvulsants, and antipsychotics. Prazosin is an α1-adrenergic receptor antagonist, which was first introduced as a treatment for high blood pressure in 1970. It reduces the adrenergic response and has the advantage of crossing the blood-brain barrier. We know that stimulation of α1 receptors induces the primitive fear response, disrupts rapid eye movement (REM) sleep, and increases non-REM sleep. We believe that Prazosin exerts its effect through a mechanism that blocks the primitive fear responses by antagonizingthe α1 receptors in the CNS and decreasing PTNMs [17].

In addition, the Best practice guide lists six specific CBTs for NMs: imagery rehearsal therapy (IRT) (Level A), systematic desensitization (Level B), lucid dreaming therapy (LDT) (Level C), exposure, relaxation, and rescripting therapy (ERRT) (Level B), sleep dynamic therapy (Level C), and self-exposure therapy (Level C). These CBTs conceptualize NMs as a learned behavior, but each treatment approaches them differently. The IRT rationale is to select a repetitive NM, to transform and write it into a new dream, and finally to rehearse it in imagination. The idea is to gain control over the NM. The ERRT model is to expose the person to his original nightmare content a little further than IRT. The participant has to write down his original NM and to identify traumatic themes that will be used when rescripting and rehearsing it. Going further than IRT, it also incorporates sleep hygiene education and modification, and relaxation for insomnia. Contrary to IRT and ERRT, LDT will train individuals to become aware that they are dreaming while they are actually dreaming and to change the scenario [18].

#### **1.3. Objectives**

**1. Introduction**

**1.1. PTSD and nightmares**

Nightmares (NM) are one of the intrusion symptom clusters of post-traumatic stress disorder (PTSD) in the fifth edition *Diagnostic and Statistical Manual of Mental Disorders* (DSM-5) [1]. The prevalence of frequent NM is 70% in individuals with PTSD compared to only 2–5% in the general population [2]. Post-traumatic nightmares (PTNMs) are different from "normal" dreams as they are recurrent frightening dreams of past traumatic events [3]. Their content may vary from an exact replay to only some components of the trauma, such as changes in time and place [3]. Another distinction is their role in PTSD. In the general population, sleep loss impacts daily functioning due to fatigue and cognitive difficulties [4], leading to poor quality of life [5]. However, in the particular PTSD context, the presence of NM seems to be related to PTSD prevalence and severity [6], and therefore, to contribute to the development

PTSD used to be considered as an anxiety disorder in the fourth edition revised *Diagnostic and Statistical Manual of Mental Disorders* (DSM-IV-TR) [8]. Now, it is part of the trauma- and stressor-related disorders in the DSM-5 [1]. Several meta-analyses, systematic reviews, and guidelines underline that general trauma-focused cognitive and behavioral treatments (CBTs) (through exposure and cognitive restructuring) are superior, or equivalent, to other types of psychological treatments, such as eye movement desensitization and reprocessing (EMDR), psychodynamic psychotherapies, or supportive techniques (e.g., [9]). They also emphasize the efficacy of selective serotonin reuptake inhibitors (SSRIs) as a pharmacological treatment [10]. However, studies also reveal that CBTs and SSRIs do not effectively resolve all PTSD symptoms in individuals who no longer meet PTSD diagnosis criteria. In fact, NMs were found to be

One approach is to conceptualize NMs in two steps after a traumatic event. First, right after the trauma, NMs would be considered as trauma-induced and would be a PTSD symptom. Later, at a second stage, they would become a learned behavior distinct from PTSD symptoms. The idea is that the person, by fearing and avoiding NM content, cannot process the information related to the event and cannot incorporate it [13]. As these NMs disrupt sleep, it can be difficult for the victims to return to sleep and they may adopt unsuitable sleep hygiene, which could lead to insomnia [14]. Therefore, new psychological and pharmacological treatments are

Recently, the Standards of Practice Committee (SPC) of the American Academy of Sleep Medicine (AASM) commissioned a task force to assess the literature on the treatment of NM disorder in general. They presented their recommendations in a Best practice guide about pharmacotherapies and CBTs for NM for adults [15, 16]. Their classification was based on study designs from "level 1" (high-quality randomized clinical trials with narrow confidence intervals) to "level 4" (case series or poor case-control studies or poor cohort studies or case

of PTSD. They could even contribute to PTSD symptom maintenance [7].

206 A Multidimensional Approach to Post-Traumatic Stress Disorder - from Theory to Practice

treatment resistant, and residual insomnia was also reported [11, 12].

**1.2. Emergence of treatments directly targeting nightmares**

emerging and tested to directly reduce NMs.

The first objective of this chapter is to review and evaluate the impact of CBTs compared to Prazosin for NM reduction, after a traumatic event in an adult population. The secondary objective is to evaluate the impact of both types of interventions on other PTSD symptoms and sleep.
