What the PHQ-8 measures
What the PHQ-8 measures

Kroenke et al. (2008) tested whether the PHQ-8 could screen for current depression in the general population. Here, current depression means symptoms in the last two weeks, not a lifetime history of ever being depressed.
Step-by-step lessons on Edexcel AS Level Psychology Contemporary study (depression): Kroenke et al.. Each one builds up to exam-style questions.