The efficacy of drug treatments for dysthymia: a systematic review and meta-analysis

CRD COMMENTARY: The aim and inclusion criteria in terms of study design, participants, intervention and outcome were clearly defined. Several relevant databases were searched, details of the search strategy were given and attempts made to locate unpublished material. Publication bias was assessed and its influence on the results explored. Methods used to assess validity according to defined criteria and extract data were described. Only studies classified as being of higher quality were eligible for inclusion. Statistical heterogeneity was assessed and subgroup analyses determined a priori. Meta-analysis was appropriate given the lack of statistical heterogeneity. Relevant details of the primary studies were presented in tabular format. The discussion includes consideration of the following limitations of the review: likely presence of publication bias; only short-term results were available; a number of papers reported results only on "completers" rather than performing a true intention-to-treat analysis; and the comparisons reported were not direct comparisons between different classes of antidepressants. It was not clear whether language restrictions were applied to the literature search or to what extent data were extracted on an intention to treat basis and methods used to select primary studies were not described. The evidence presented supports the authors' conclusions.