Time frame: Changes from baseline to after 8-week treatment and at end of 16-week follow up.
The PHQ-9 is self-report, nine-item screening tool for depression. The tool rates the frequency of depressive symptoms based on DSM-5 criteria for major depression, asking respondents rate each item according to the following instructions, "Over the last 2 weeks how often have you been bothered by any of the following:" Items are rated via four choices: 0= not at all, 1= several days, 2 = more than half the days, and 3= nearly every day. Scores are summed with higher scores indicating higher level of psychological distress. The PHQ-9 has been shown to have a sensitivity of 88% and specificity of 88% for Major Depression, with a Cronbach alpha of .89 (Kroenke et al., 2001). It has suggested interpretations of 5-9 = mild, 10-14 = moderate, 15-19 = moderate severe, and 20-27 = severe depression.