Ethological approaches to psychiatric disorders: focus on depression and schizophrenia.

Behavioural observation of psychiatric patient groups using ethological methodology has never been a mainstream approach in psychiatry. In the present review article it is argued that the assessment of non-verbal behaviour in psychiatric disorders has much to offer to clinicians. Based on a Medline survey, the literature on ethological observation of patients with depression and schizophrenia was reviewed. Ethological observation of psychiatric patient groups has the potential to improve prediction of course and outcome of severe psychiatric disorders at a very early stage. Disadvantages of the ethological approach lie within its technical requirements and its inherent time-consuming evaluation of data. A full appreciation of psychiatric disorders may require answers to questions to the proximate causes and evolutionary (Darwinian) trajectories of behaviour, an approach that may well be expanded to maladaptive cognition and emotion.