Adjunctive treatment with quetiapine for major depressive disorder: are the benefits of treatment worth the risks?

Quetiapine was approved in 2009 and 2010 for the adjunctive treatment of major depressive disorder (MDD) in several countries worldwide, including the European Union, Canada, the United States, and Australia. These approvals followed three industry sponsored trials of quetiapine versus placebo added to an antidepressant for depression in adults who had an inadequate response to at least six weeks of antidepressant treatment. All three trials showed statistically significant improvements in symptoms of depression compared with placebo.1

Pharmacoepidemiological studies in the United States and Canada have shown a shift in practice over the past decade in the use of antipsychotic drugs in the management of MDD. The US National Ambulatory Medical Care Survey found that the percentage of office visits in which a non-psychotic depression was diagnosed that included adjunctive antipsychotic treatment increased from 4.6% (95% confidence interval 2.9% to 6.3%) in 1999-2000 to 12.5% (9.7% to 15.3%) in 2009-10.2 Quetiapine was the most frequently used antipsychotic drug for augmentation from 2007 to 2010. US data have also shown declining rates of psychotherapy among antidepressant users as the percentage of patients receiving antipsychotic drugs has increased.3 Over the past decade, Canada has seen a large and preferential increase in the use of quetiapine, which has been the most commonly prescribed antipsychotic since 2007. In 2005, 3.2 prescriptions for quetiapine by family physicians were dispensed per 100 Canadians; by 2012 this had increased to 12.0 per 100.4 Mood disorders were the most common diagnoses associated with quetiapine prescriptions.

With an estimated global point prevalence of 4.4%,5 MDD is a frequently encountered problem in clinical practice. Approximately 33% of people in the STAR*D sample (a prospective study of 3671 people with MDD) entered remission after initial selective serotonin reuptake inhibitor treatment; this increased to 50% after a switch …