Depression following adult, non-penetrating traumatic brain injury: A meta-analysis examining methodological variables and sample characteristics

BACKGROUND Depression is one of the most frequently reported psychological problems following TBI, however prevalence estimates vary widely. Methodological and sampling differences may explain some of this variability, but it is not known to what extent. METHODS Data from 99 studies examining the prevalence of clinically diagnosed depression (MDD/dysthymia) and self-reports of depression (clinically significant cases or depression scale scores) following adult, non-penetrating TBI were analysed, taking into consideration diagnostic criteria, measure, post-injury interval, and injury severity. RESULTS Overall, 27% of people were diagnosed with MDD/dysthymia following TBI and 38% reported clinically significant levels of depression when assessed with self-report scales. Estimates of MDD/dysthymia varied according to diagnostic criteria (ICD-10: 14%; DSM-IV: 25%; DSM-III: 47%) and injury severity (mild: 16%; severe: 30%). When self-report measures were used, the prevalence of clinically significant cases of depression differed between scales (HADS: 32%; CES-D: 48%) method of administration (phone: 26%; mail 46%), post-injury interval (range: 33-42%), and injury severity (mild: 64%; severe: 39%). CONCLUSION Depression is very common after TBI and has the potential to impact on recovery and quality of life. However, the diagnostic criteria, measure, time post-injury and injury severity, all impact on prevalence rates and must therefore be considered for benchmarking purposes.