[Therapy refractory depression].

Patients who fail in an adequate trial of a standard antidepressant drug (corresponding to 150 mg/d imipramine over a minimal period of 4 weeks) are defined as treatment resistant. According to these guidelines a substantial number of patients is not sufficiently treated and, thus, should be reassessed for dosage and length of antidepressant medications. If patients fail to a sufficient treatment a response may be achieved if they are switched to an alternative drug and/or if biochemically differently acting antidepressants are combined. Furthermore, an increasingly popular approach to handle treatment resistance is the use of augmentation strategies. Among these, lithium and thyroid T3 are the most well studied with the most consistently positive results. As non-pharmacological augmentation approach partial sleep deprivation has proved to be effective in combination with antidepressant medication. Finally, patients who had no or only a partial response to several treatments with antidepressants may benefit from electroconvulsive therapy.