“…Examples of the analyses Kendell overviews include the work of Overall and others (8), who used factor analysis to delineate anxious-tense depression, hostile depression, and retarded depression; Pilowsky and others (9), who defined endogenous and other depressions according to numerical taxonomy; Paykel (10), who used cluster analysis to define psychotic depressives, anxious depressives, hostile depressives, and young depressives with personality disorder; and Kiloh and others (11), who used multivariate analysis to define endogenous depression as a categorical illness and neurotic depression as a dimensional condition that included young individuals with personality disorders, those with anxiety and depression, and those who were angry and hostile.…”