ABSTRACT
In addition to personal psychological characteristics, biological factors may in some instances maintain psychological problems. Abnormal levels of physiological arousal, dysregulation of neurotransmitter systems, dysregulation of neuroendocrine systems, abnormal circadian rhythms and a variety of abnormalities in other bodily systems have been implicated (with varying degrees of empirical support) in the maintenance of some psychological problems (Roberts, 2003; Rutter, 2002a). Typically, specific biological maintaining factors are associated with specific conditions. For example, megacolon (an enlarged colon) is associated specifically with the maintenance of encopresis (see Chapter 7) and the neuroendocrine consequences of starvation are associated specifically with the maintenance of anorexia nervosa (see Chapter 17). Because of the specificity of biological factors further discussion of them will be reserved for Chapters 6 to 18, in which specific problems are discussed in detail.
