Parker G, et al. - Researchers sought to differentiate clinical and non-clinical depression via a set of symptoms. They assessed a sample of 140 patients attending a clinical service for those with mood disorders together with 40 individuals refusing ever experiencing a clinical episode of depression. A questionnaire capturing many symptoms of depression as well as illness correlates was administered to the participants. They developed two models for classifying clinical depression: the first involving individuals feeling hopeless and also being suicidal or at risk of self-harm; and the second involving a symptom set corresponding to DSM-5 criteria but with only five making significant independent contributions to diagnostic differentiation. The study thereby proposes a strategy for more accurately differentiating clinical and non-clinical depression in more representative samples, so supporting resolution of key features, and determining whether a monothetic or polythetic diagnostic symptom criterion model is optimal.