Emerging treatments for common mental health conditions affecting Veterans: D-cycloserine interventions
Abstract: There are a number of treatments that have an emerging evidence base and could be considered in the management of common mental health conditions affecting veterans. Emerging and adjunct treatments are typically considered when an individual’s adherence or response to accepted or conventional treatment/s is poor (i.e., chronic, treatment-resistant, or treatment-refractory mental health conditions). The aim of the rapid evidence assessment (REA) was to identify and critically evaluate the current evidence on emerging and adjunct treatments for posttraumatic stress disorder (PTSD) and common mental health conditions affecting veterans. From the four databases that were searched, 25 studies met the inclusion criteria, including 12 secondary sources: four (4) systematic reviews (SRs) and eight (8) SRs with accompanying meta-analyses (MAs). The studies within these secondary sources (i.e., those contained within SRs and MAs) were extracted to a database containing the primary sources (i.e., randomised controlled trials, RCTs). From this collated set of articles (281 in total), all studies that did not meet the inclusion criteria were excluded (e.g., cohort and case-control studies), and all duplicate studies were removed (i.e., often the same RCT would appear in multiple SRs and MAs; as well as being directly retrieved by the search strategy). The final set of articles included 13 RCTs. The findings from these studies were narratively synthesised, and risk of bias assessments were conducted for each RCT. Strengths of the REA include the focus on peer-reviewed Level I and Level II evidence (NHMRC, 2009) from scientific journals in the fields of health, medicine, psychiatry, and psychology (including a specialist database developed by the US Department of Veterans’ Affairs focusing on literature relevant to veterans with PTSD). Limitations of the REA include the exclusion of potentially relevant papers that were published prior to 2017 and the exclusion of non-English language papers. It is difficult to draw conclusions and recommendations regarding DCS interventions from the body of evidence considered by the REA. DCS is proposed to enhance fear extinction or extinction learning via partial agonism of the NMDA receptor (neurobiological mechanism of action). Thus, most of the included studies examined the effects of DCS administration in combination with exposure-based psychotherapy for anxiety disorders. Some studies appear to indicate that DCS improves outcomes from evidence-based psychotherapy. However, due to the mixed findings across studies, it is difficult to recommend the use of DCS interventions in specific clinical situations. Further high-quality research is required.