Outcome measures are dependent on the type of therapy phase:

In the treatment of depressive illness, the acute or short phase of 6–8 weeks is focused on response and remission in terms of symptom reduction. The continuation or medium phase of the next 6–8 months of treatment focuses on social functioning and subjective quality of life.

In the acute treatment, the Hamilton Depression Scale (HAM-D17) is the internationally most frequently used scale, although the total score of all 17 items rarely has been found to be a valid measure of severity of depressive illness. the six-item Hamilton subscale (HAM-D6), on the other hand, has consistently been shown to be a valid scale to measure response or remission in controlled clinical trials of antidepressants. Both the HAM-D6 and the analogous six-item Montgomery-Asberg Depression Scale (MADRS6) have been able to demonstrate dose-response relationship with different antidepressants, in contrast to HAM-D17.

In the continuation therapy, national norm scores on self-rating scales measuring social functioning (e.g. SF-36) or positive psychological well-being questionnaires (e.g. WHO-5) are the goal of treatment. It has been demonstrated that after only 12 weeks of therapy, social functioning is restored in patients with major depression treated with SSRIs, i.e. they obtain scores on the SF-36 subscale of social well-being within the range of the general population scores.