Publication bias in meta-analyses of Posttraumatic Stress Disorder interventions

Meta-analyses are susceptible to publication bias, the selective publication of studies with statistically significant results. If publication bias is present in psychotherapy research, the efficacy of interventions will likely be overestimated. This study has two aims: (1) investigate whether the application of publication bias methods is warranted in psychotherapy research on posttraumatic stress disorder (PTSD) and (2) investigate the degree and impact of publication bias in meta-analyses of the efficacy of psychotherapeutic treatment for PTSD. A comprehensive literature search was conducted and 26 meta-analyses were eligible for bias assessment. A Monte-Carlo simulation study closely resembling characteristics of the included meta-analyses revealed that statistical power of publication bias tests was generally low. Our results showed that publication bias tests had low statistical power and yielded imprecise estimates corrected for publication bias due to characteristics of the data. We recommend to assess publication bias using multiple publication bias methods, but only include methods that show acceptable performance in a method performance check that researchers first have to conduct themselves