Mindfulness-based interventions (MBIs) have become widely used for common mental disorders (CMDs) but the state of the evidence has not been sufficiently investigated. The aims for this study were: (1) to quantify the effect size of MBIs for CMDs in the acute phase; (2) to explore moderator variables; and (3) to evaluate the evidence status of MBIs for the CMDs it has been tried for. A comprehensive systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted. RCTs that evaluated MBI and included patients with a primary manifest CMD was included. Methodological quality, the risk of bias, publication bias and evidence status were assessed. Literature searches gave 2448 hits and 19 studies were included. MBIs were more effective than no treatment (g = 1.07) and treatment-as-usual (g = 0.40) but not in comparison to placebo (g = 0.17) or other active treatments (g = −0.01). Methodological quality was negatively correlated with outcome. For all psychiatric disorders it has been tested, MBIs were judged to have weak or no empirical support. The conclusion of the study is that the evidence-base for MBIs for CMDs in the acute phase is weak.

Benzodiazepines are assumed to cause drowsiness and sedation. Rating scales such as the Massachusetts General Hospital Sedation Scale and the Morning Evaluation of Drug Induced Sedation Scale allow testing of this hypothesis and assessment of the effects of benzodiazepines. We performed a five-week study of prazepam in 63 anxious outpatients. Plasma levels of desmethyldiazepam were assessed weekly. Placebo was given the first week, followed by active drug for three weeks, and placebo the final week. One group received prazepam 30 mg/h, the other received prazepam 10 mg three times per day. Drowsiness-sedation and anxiolytic efficacy were assessed at baseline and weekly. Plasma desmethyldiazepam levels were similar in both treatment groups. Efficacy was profound in both groups. Drowsiness-sedation measured high at baseline and decreased significantly (P=0.05) over the 3 weeks when active drug was administered. Sedation decreased by as much as 40%. Sleep was improved with prazepam, and this may have resulted in decreased drowsiness. We conclude that anxious outpatients have significant levels of drowsiness-sedation and that treatment with benzodiazepines reduces the occurrence of this symptom.