Chronic depression and treatment-resistant depression are highly important from a clinical perspective. Despite this clinical relevance, relatively few trials have examined the effects of psychological interventions and only a limited number of meta-analyses of these trials have been conducted. No recent meta-analysis has focused on the effects of psychotherapies for chronic and treatment-resistant depression compared with control conditions (care-as-usual, waitlist, pill placebo, others). We decided to conduct a new meta-analysis of psychotherapies for chronic and...