Objective: Adjunctive antipsychotic therapy can be prescribed to patients with depression who have inadequate response to antidepressants. This study aimed to describe the use of adjunctive antipsychotics over a time period that includes the authorization in 2010 of prolonged-release quetiapine as the first adjunct antipsychotic to be used in major depressive disorder in the UK.Research design and methods: Adults with an episode of depression between January 1, 2005 and July 31, 2013 were identified from antidepressant prescriptions and depression diagnoses in the UK Clinical Practice Research Datalink. Patients with prior records of bipolar disorder, schizophrenia, or antipsychotic prescriptions were excluded.Main outcome measures: Rates of adjunct antipsychotic initiation and characteristics and management of patients with adjunct antipsychotics.Results: Of 224,353 adults with depression, 5,807 (2.6%) initiated adjunct antipsychotic therapy. Overall incidence of antipsychotic initiation was 7.4 per 1,000 patient-years (95% CI=7.2-7.6). Between 2005-2013, the overall rate did not change, although initiation of typical antipsychotic prescribing decreased (57.7% to 29.1%), while atypical antipsychotics, especially quetiapine (14.1% to 49.7%), increased. Of those who initiated antipsychotics, 59.4% were women (typical antipsychotics=62.8%, atypical antipsychotics=56.1%) and median age was 46 years (typicals=49 years, atypicals=44 years).Conclusions: Antipsychotics were rarely used to treat depression between 2005-2013 in UK primary care. The choice of adjunctive antipsychotic therapy changed over this time, with atypical antipsychotics now representing the preferred treatment choice. However, information on patients strictly cared for in other settings, such as by psychiatrists or in hospitals, potentially more severe patients, was unavailable and may differ. Nonetheless, the high off-label use in primary care, even after the authorization of quetiapine, suggests that there is a need for more licensed treatment options for adjunctive antipsychotic therapy in major depressive disorder.