This book describes the development of a behavioral approach to the diagnosis of depression, the CORE system, and demonstrates its superiority to previous symptom-based diagnostic systems. The authors suggest that the psychomotor signs elicited may indicate the likely pathogenesis of melancholic depression. This is therefore a challenging new account of the classification and neurobiology of depression, that is certain to interest all clinicians involved in the evaluation or treatment of such patients. The CORE measure itself is incorporated as an appendix.