Sexual assault victims (SAV) have an elevated risk of developing posttraumatic stress disorder (PTSD). Trauma-focused cognitive-behavioural therapy (CBT) is an effective first-line treatment for this pathology. However, although sleep disturbances are a common complaint in SAV with PTSD, trauma-focused CBT does not directly address this symptom. Posttraumatic nightmares are widespread among SAV. Trauma-related sleep disturbances are associated with significant impairment in general functioning and quality of life (mental and physical health), and contribute to the maintenance of PTSD symptoms. This study evaluates the efficacy of sequential nightmare therapy (imagery rehearsal therapy; IRT) and trauma-focused CBT, in comparison to CBT alone. Forty-two SAV suffering from PTSD and sleep difficulties were recruited and randomly assigned to the experimental (IRT+CBT) or control condition (waiting period followed by CBT alone). Participants were administered a clinical interview and a series of questionnaires assessing PTSD symptoms, general functioning and quality of life.

Inclusion Criteria:

• over 18 years of age;
• able to understand and speak French;
• history of unwanted sexual experience;
• PTSD diagnosis according to DSM-IV-TR;
• sleep complaints, as established by Pittsburgh Sleep Quality Index score ≥ 5 and a mean of one or more NM per week for at least one month;
• if psychotropic medication was used, (antidepressant, antianxiety, antipsychotic or hypnotic medication) stable for a minimum of three months;
• available for in-person assessments and therapy sessions.

Exclusion Criteria:

• past or present psychotic episode, bipolar disorder or organic mental disorder (e.g. dementia);
• substance use disorder;
• sleep apnea diagnosis;
• use of prazosine to treat nightmares;
• presently in treatment for psychological difficulties;
• significant suicidal thoughts requiring immediate intervention.