Is there a relationship between clinical efficacy and antidepressant dosage in major depression ?

Several methodological approaches enable to study dose-efficacy relationships with antidepressants : dose range studies with or without placebo, studies of dose augmentation in non responders, meta-analyses and concentration-efficacy studies. With tricyclic antidepressants, published data on dose-efficacy relationships are relatively scarce but often show that the higher dose is more efficacious than the lower dose. Results of concentration-efficacy studies show heterogeneity between tricyclic antidepressants. With selective serotonine reuptake inhibitors, systematic dose-efficacy and concentration-efficacy studies are available. They show that there is neither dose-efficacy nor concentration-efficacy relationships with SSRI. Venlafaxine has been systematically studied for a dose-efficacy relationship and results show a linear dose-efficacy relationship. Practical implications of these results are discussed.