Classification of the Behavior Disorders

that in psychology, because of the conflict of numerous terminologies and syst ems, development of a nosological system should actually precede the study of functional relationships. They argue that meaningful research requires the isolat ion and identificat ion of basic variables. Regardless of how one conceives of the proper approach to an underst anding of the be­ havior disorders, classificat ion has an important, alt hough limited, role to play in this field. In this chapter we shall emphasize theoretical formula­ tions, exper imental and stat ist ical studies, and allied research broadly con­ cerned wit h the origin, development , and classificat ion of the behavior disorders. Biochemical theories and experiment s were reviewed by Hoffer in the 1960 Annual Review and will not be touched on here. Evaluative studies of psychotherapy are reviewed in ano ther chap ter. Ref erence will be made to drug studies and the shock ther apies only in so far as they re­ flect on or represent applications of theory to treatment. Broadly speaking, the approach taken was selective. Only a fract ion of the st udies reviewed will be described. THE PROBLEM OF DIAGNOSIS