The primary objective is to examine changes in pre/post-augmentation healthcare costs and resource utilization in patients diagnosed with major depressive disorder (MDD) who augment their current antidepressant therapy with an atypical antipsychotic.

Inclusion Criteria:

Patients who meet the following criteria will be included in the study:

• aged 18 to 64 years
• diagnosis of major depressive disorder during the study timeframe (ICD 9 codes 296.2, 296.3, 311)
• evidence of at least 6 consecutive claims for traditional antidepressant therapy with a 30 day supply or at least 2 claims with a 90 day supply (consecutive defined as ≤15 days gap)
• must be continually enrolled during the study timeframe and have both medical and pharmacy benefits
• evidence of at least 4 consecutive claims for an atypical antipsychotic prescription with a 30 day supply or 2 claims with a 90 day supply (consecutive defined as ≤15 days gap)
• evidence of antidepressant therapy for at least 60 consecutive days prior to the initiation of atypical antipsychotic
• After at least a 60 day trial of traditional antidepressant medications, patient augments with an atypical antipsychotic medication for at least 4 months.

Exclusion Criteria:

Patients are excluded if they:

• have any claims for a diagnosis of schizophrenia, schizoaffective or bipolar disorder during the study period
• have Electroconvulsive therapy (ECT) during the study period
• new augmentation with mood stabilizers, L-thyroxine (T4), L-Thyronine (T3), buspirone, stimulant, or others during the post-period (table 1)
• are pregnant during the study period
• patients with Medicare or Medicaid

The population is identified as patients diagnosed with MDD who are treated with antidepressants and subsequently augment with atypical antipsychotic therapy.