 The category of psychosis, employed for extreme states of disorder affecting perceptual capabilities (in hallucinations) and reasoning (in delusions), are introduced here, followed by a sample of particular disorders among the many that have received philosophical attention: addiction, anorexia, psychopathy (anti-social personality disorder), and depression. Philosophical analyses of other diagnostic categories include defiant disorder (Potter 2014), borderline personality (Potter 2009); obsessive compulsive disorder (Glas 2013; Szalai 2016); dissociative identity disorder (Braude 1991; Radden 1996; Worrell &amp; Denham 2016; Maiese 2016); anxiety (Horwitz &amp; Wakefield 2012), and neurodevelopmental conditions such as autism spectrum disorder (Baron-Cohen, Lombardo, &amp; Tager-Flusberg 2013).