What defines treatment-resistant depression?

Treatment-resistant depression is characterized by the persistence of depressive symptoms despite a patient undergoing at least two adequate trials of antidepressant medications. These trials must involve different classes of antidepressants and be administered at therapeutic doses for a sufficient duration. The concept is essential in clinical practice as it guides the clinician toward alternative treatment strategies after traditional approaches have failed.

Defining treatment resistance in this manner allows for a clear demarcation between typical depressive episodes that might respond to initial treatments and those that become more complex, requiring further interventions such as psychotherapy, augmentation strategies with other medications, or even alternative modalities like electroconvulsive therapy.

The other options do not capture the essence of treatment resistance as appropriately. Length of depressive episodes or the occurrence of symptoms related to life changes are not definitive indicators of treatment resistance; they may be part of the spectrum of depressive disorders but do not specifically denote a failure to respond to treatment. Additionally, the client's refusal of treatment introduces a variable related to adherence rather than resistance to treatment itself.