| A comprehensive theory of major affective disorders is proposed. The theory posits the interaction of four levels of variables: (1) predisposing variables; (2) intermediate variables; (3) intrapsychic processes; and (4) clinical manifestations.;Predisposing variables are biologic and social factors present at birth that form a biosocial matrix: genetic endowment, non-genetic CNS functions, and socio-economic and cultural conditions. What is inherited is a polygenically influenced constitutional predisposition for mood disturbance, in consequence of which it is assumed that the degree of predisposition and the severity of potential environmental stressors are continuously distributed in the general population. A variety of predispositions may be inherited that provide a variety of pathways to the groups of affective disorders.;Intermediate variables fill the wide gap between presumed genetic endowment and symptomatic breakdown. Intermediate variables are divided into two classes: (a) individual attentional, perceptual, psychophysiological response dispositions; and (b) interpersonal and transactional systems. The first class includes polygenically inherited aspects of "temperament" succeptible to psychophysiological, neurophysiological, and perceptual methods of measurement. The leading biochemical-neurophysiological theories, such as the catecholamine hypothesis are examined. The conclusion drawn is that no single gene or biochemical event leads inevitably to breakdown. The variety of biologic phenomena reflects the inheritance of multi-loci, heterogenous predispositions differentially affected by environmental stressors. The second class of intermediate variables, transactional processes, represent the active factors within the enduring environmental system of the family. There are four subgroups of this second class: (a) intrafamilial communication patterns; (b) family role structure; (c) the intrafamilial subculture of shared beliefs, myths, rules, and values; and (d) extrafamilial factors. Vulnerability for developing affective disorders necessarily involves both genetically influenced response dispositions and non-genetically influenced psychosocial patterns. That environmental factors activate predispositions is interpreted both along biochemical-neurophysiological and psychological both along biochemical-neurophysiological and psychological lines.;Intrapsychic processes are viewed as the outcome of (1) predisposing and intermediate variables and (2) individual development. Biologic and psychological levels of discourse are reconciled within the principles guiding the entire hypothesis. Cognitive, emotional and motivational patterns manifested as part of affective disorders are the outcome of biological and psychosocial processes. |
