The prevalence of depression in adult onset idiopathic dystonia: Systematic review and metaanalysis.

Adult onset idiopathic dystonia (AOID) is the third most common movement disorder in adults. Co-existing depressive symptoms and disorders represent major contributors of disability and quality of life in these patients, but their prevalence remains unclear. We investigated the point prevalence of supra-clinical threshold depressive symptoms/depressive disorders in AOID in a systematic review with qualitative synthesis and meta-analysis. Our search identified 60 articles suitable for qualitative synthesis and 54 for meta-analysis. The overall pooled prevalence of either supra-clinical threshold depressive symptoms or depressive disorders was 31.5 % for cervical dystonia, 29.2 % for cranial dystonia, and 33.6 % for clinical samples with mixed forms of AOID. Major depressive disorder was more prevalent than dysthymia in cervical dystonia, whereas dysthymia was more prevalent in cranial dystonia. In cervical dystonia, the prevalence of supra-clinical threshold depressive symptoms screened by rating scales was higher than that of depressive disorders diagnosed with structured interviews. Prevalence studies using rating scales yielded higher heterogeneity. More research is warranted to standardize screening methodology and characterization of mood disorders in AOID.