This is an assessment of the efficacy of venlafaxine-HCL augmentation with the neuroleptic quetiapine in treatment resistant depression.

We examine the efficacy of Venlafaxine-HCL augmentation with the neuroleptic Quetiapine in treatment resistant depression in a double-blind randomized clinical trial. Secondary objective is the evaluation of pharmacogenetic factors contributing to drug efficacy in treatment resistant depression.

Inclusion Criteria:

• Female and male inpatients with a major depressive disorder without psychotic features or with a depressive episode within a bipolar I or II disorder without psychotic features
• Ages between 20 and 70 years
• Total score greater than 18 on the Hamilton Depression Rating Scale
• Documentation of at least one ineffective antidepressant drug trial under adequate dosage for at least 6 weeks in the current episode

Exclusion Criteria:

• Other psychiatric axis I disorders than those mentioned as Inclusion criteria
• Acute suicidality (Item 3 of the Hamilton Depression Rating Scale greater than 2)
• Drug or alcohol addiction
• Patients with severe hepatic, cardiovascular, neurologic, metabolic or malignant disorders
• Documentation or report of a previous ineffective treatment trial with venlafaxine, lamotrigine or quetiapine
• Functional kidney disorders
• Untreated hypertension
• Acute treatment with thyroid hormone (less than 3 months)
• Pregnant or nursing patients
• Women of childbearing age without effective contraception