The goals of treatment should be to achieve remission, reduce relapse and recurrence, and return to previous level of occupational and psychosocial function.

Full remission is defined as a two-month period devoid of major depressive signs and symptoms (American Psychiatric Association, 2013: Diagnostic and Statistical Manual of Mental Disorders, 5th Edition). If using a PHQ-9 tool, remission translates to PHQ-9 score of less than 5 (Kroenke, 2001). Results from the STAR*D study showed that remission rates lowered with more treatment steps, but the overall cumulative rate was 67% (Rush, 2006).

Response is defined as a 50% or greater reduction in symptoms (as measured on a standardized rating scale). Partial response is defined as a 25-50% reduction in symptoms. This definition is based on how the depression literature defines response.

Response and remission take time. In the STAR*D study, longer times than expected were needed to reach response or remission. In fact, one-third of those who ultimately responded did so after six weeks. Of those who achieved remission by Quick Inventory of Depressive Symptomatology (QIDS), 50% did so only at or after six weeks of treatment (Trivedi, 2006b). If the primary care clinician is seeing some improvement, continue working with that patient to augment or increase dosage to reach remission. This can take up to three months.

A reasonable criterion for extending the initial treatment: assess whether the patient is experiencing a 25% or greater reduction in baseline symptom severity at six weeks of therapeutic dose. If the patient's symptoms are reduced by 25% or more, but the patient is not yet at remission, and if medication has been well tolerated, continue to prescribe. Raising the dose is recommended (Trivedi, 2006b).

Improvement with psychotherapy is often a bit slower than with pharmacotherapy. A decision regarding progress with psychotherapy and the need to change or augment this type of treatment may require 8 to 10 weeks before evaluation (Schulberg, 1998).