**5. Conclusions**

and should be interpreted with caution for Prazosin studies, more particularly for the PTSD

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

Finally, systematic reviews and meta-analysis have previously been published on these new psychological treatments and on Prazosin (e.g., [17, 74–78]). The main advantages of the present study are, compared to the previous ones, to have screened studies written in English and French and to have considered randomized and nonrandomized studies. Also, if looked at all types of nightmares, treatments not only considered imagery rehearsal treatments, in an adult population with PTSD evaluated by validated questionnaires or structured interviews. At last, this study combined both a meta-analysis and a systematic review on CBT for nightmares and Prazosin, which allowed discussing their respective impacts and advantages.

Despite the contribution of this study, future trials should consider some of the weaknesses observed in this meta-analysis when NM is in a PTSD context. First, efforts should be made to standardize the methodology used by including a control group, reporting outcomes at follow-

Also, the different methods used to evaluate NM frequency in this meta-analysis emphasized that standardization was needed for questionnaire administration, NM definition, and treatment format. In fact, we observed that all Prazosin studies used the CAPS, a retrospective measure to evaluate NM, while CBTs used both self-reported retrospective and prospective measures like home daily logs. More precisely, all Prazosin studies evaluated NM using the CAPS-B2 item, compared to CBTs, which retrieved items evaluating NM from various retrospective questionnaires or home sleep logs. Only two studies, by the same author [36, 79], included objective sleep measurements (polysomnography, PSG). To date, prospective daily logs are considered the gold standard for the measurement of NM frequency [80], as selfreports underestimate current NM frequency [81]. Therefore, results could differ according to the method of measurement used and caution is advised in evaluating to Prazosin impact.

Only a few studies specified NM definition. Even if most studies adhered to a frequency cutoff of one weekly nightmare minimum or an average of two or more NM per week, it is not clear what participants understood by NM. In Prazosin studies, the CAPS-B2 item refers to the frequency and the intensity of recurrent distressing dreams related to the traumatic event. Therefore, we could wonder if the impact of Prazosin was on NM frequency or on NM distress. This could influence the interpretation of results. In addition, we could not retrieve information regarding NM content. As we know, PTNMs may be trauma-related or replicative trauma [3]. Therefore, it would have been interesting to have access to this information in order to evaluate which kind of PTNM contents was targeted and by which CBT. In fact, each treatment has its own rationale and degree of exposure to the selected NM. Therefore, this information would be an indicator of which PTNM contents favor each treatment and could help to refine

Disparities were also observed in sample characteristics, with women being less represented than men, more particularly in Prazosin studies; and with combat experience and sexual

symptom variable [47].

**4.5. Further studies**

guidelines.

ups, and giving NM definition or content.

We know CBTs and SSRIs do not effectively resolve all PTSD symptoms, as nightmares were found to be treatment resistant and residual insomnia was reported. From the positive results of this meta-analysis, we know specific NM treatments (Prazosin or CBTs) contribute to NM reduction. These treatments also demonstrate PTSD and sleep symptom reduction. The overall conclusion of this meta-analysis is that treating NM with Prazosin or CBTs directly is interesting and can be a way to improve conventional CBTs for PTSD. However, no consensus or guidelines are available to treat PTNMs. From these outcomes, clinicians can conclude that NM can affect the efficacy of first-line PTSD treatments, and new treatments are developed to solve this problem, while in sleep research PTSD outcomes should be reported.
