Psychiatric diagnosis and clinical trial completion rates: analysis of the FDA SBA reports

Completion rates may affect the safety and efficacy evaluations of psychotropics. We assessed completion rates in clinical trials evaluating psychotropics for five psychiatric disorders. We also examined differences in completion rates between psychotropics and placebo in each diagnostic category. We reviewed clinical data in the Food and Drug Administration summary basis of approval reports for 20 psychotropics evaluated for the treatment of depression, schizophrenia, obsessive compulsive disorder (OCD), generalized anxiety disorder (GAD), or panic disorder, consisting of 19 710 patients. Patients with OCD had the highest completion rates (78.0%), followed by patients with panic disorder (74.4%), GAD (69.2%), depression (64.7%) and schizophrenia (49.0%). Patients assigned to placebo had significantly lower completion rates in antipsychotic clinical trials. Patients assigned to psychotropics in OCD trials had significantly lower completion rates compared to the placebo group. A greater number of early terminations relating to a lack of efficacy was seen among patients assigned to placebo (17.4%) compared with patients assigned to psychotropics (12.2%). A greater number of early terminations relating to adverse events was seen among patients assigned to psychotropics (10.4%) compared with patients assigned to placebo (4.8%). Our findings suggest that psychiatric diagnosis and treatment assignment (placebo vs psychotropic) were associated with completion rates in clinical trials. These findings may help in the design of future psychopharmacology clinical trials.