The study evaluates the ABCB1-genotype dependent efficacy of a quick dose-escalation strategy within 28 days of treatment with approved antidepressants that are known substrates of the P-glycoprotein, an efflux pump of the blood-brain barrier expressed by the ABCB1 gene.

Moreover, the study evaluates ABCB1-genotype dependent side-effects of approved antidepressants that are known substrates of the P-glycoprotein, an efflux pump of the blood-brain barrier expressed by the ABCB1 gene.

Inclusion Criteria:

• Male and female patients
• Age between 18 and 80 years
• Inpatients with a DSM-IV diagnosis of Major Depression
• single episode or recurrent
• moderate to severe intensity
• without psychotic features
• Inpatients with a DSM-IV diagnosis of bipolar disorder I or II
• current episode with depressive symptoms
• moderate to severe intensity
• without psychotic features
• HAM-D score at the time of inclusion in the study ≥ 14
• Patient has already been adjusted to one of the following antidepressants in a dose which is still under the defined normal-dose:
• paroxetine < 40 mg/d
• sertraline < 100 mg/d
• citalopram < 40 mg/d
• escitalopram < 20 mg/d
• venlafaxine < 225 mg/d
• amitriptyline < 150 mg/d
• amitriptylinoxide < 150 mg/d
• nortriptyline < 150 mg/d
• trimipramine < 150 mg/d

Exclusion Criteria:

• Acute suicidality (HAM-D Item 3 score > 2)
• Acute alcohol-, hypnotics-, analgesics- or psychopharmacological intoxication or delirium
• Current alcohol dependence, or dependencies from other psychotropic substances
• Severe medical or neurological diseases: patients with severe hepatic (severe impairment of liver function, cirrhosis of the liver), renal (kidney malfunctions), cardiovascular (recent myocardial infarction, instable heart disease), neurological diseases (e.g. multiple sclerosis, Parkinson, dementia)
• Patients incapable of giving informed consent
• Pregnant or breast-feeding women
• Women of reproductive age without effective contraception
• Simultaneous participation in other clinical trials or participation in an other clinical trial within 6 weeks before the start of the study
• Hypersensitivity to the study medication or to one of the ingredients of the medication
• Simultaneous treatment with another antidepressant besides study medication (exception: trazodone up to 75 mg/d, mirtazapine up to 15 mg/d, trimipramine up to 50 mg/d)
• Simultaneous treatment with mood stabilizers or neuroleptic drugs (exception: quetiapine up to 50 mg/d, olanzapine up to 5 mg/d)
• Exclusion criteria of the study medication