Published double-blind, randomised controlled trials (RCTs) of citalopram versus placebo in adult participants (aged over 18 years) diagnosed with major depressive disorder were eligible for inclusion. Major depressive disorder had to have been diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM)-III, DSM-IIIR, or DSM-IV, or the International Classification of Diseases (ICD)-9 or ICD-10. Three-arm trials with another comparator were included if the data on placebo versus citalopram was available. The primary outcome was remission, and secondary outcomes were response and reduction in the severity of depression (definitions provided in the review). Trials that involved patients with severe medical illness, other psychiatric disorder or substance abuse were excluded, as were studies of major depressive disorder that focused on relapse prevention, treatment augmentation or treatment-resistant cases.
The included trials studied citalopram (10-80mg daily dose) versus placebo in participants with a mean age of 42 years (range 18 to 74 years) who were generally diagnosed with moderate to severe major depressive disorder . Most trials had mainly female participants, and most were conducted in out-patient settings. All participants were diagnosed with major depressive disorder using the DSM criteria. Most studies had a duration of between two and eight weeks, one study had a duration of 24 weeks.
One reviewer undertook study selection.