Behavioural structure and mechanisms of anorexia: calibration of natural and abnormal inhibition of eating.

The study of experimentally induced anorexia poses a problem for investigations of the processes controlling food intake. Inhibition of food consumption may arise from a specific intervention in a physiological system controlling nutritional requirements or from non-specific changes leading to the suppression or contamination of behaviour. The present experiment used the analysis of the structure of behaviour to distinguish between normal anorexia (natural development of satiation) and pathological anorexia brought about by intestinal discomfort (injection of lithium chloride) or adulteration of food (quinine added to diet). The treatments produced marked changes in parameters of feeding and in the frequencies of behaviours associated with eating. Both lithium chloride and quinine treatments gave rise to a slow rate of eating accompanied by a disordered temporal sequence of eating, grooming and resting. This behavioural calibration of anorexia can contribute to the behavioural pharmacology of feeding by helping to diagnose drugs which facilitate normal processes of satiation and those which act via a non-specific disruption of behaviour.