Abnormal behavior patterns in rhesus monkeys: symptoms of mental disease

This paper describes the morphology of abnormal behavior of rhesus monkeys which had experienced a certain degree of social isolation. Analysis of the morphology of the behavior starts from the hypothesis that abnormal activities should preferably be interpreted as distortions of normal behavior. The results indicate that all abnormal activities seemed to be symptoms of one social deprivation syndrome, because all activities could tentatively be interpreted as more or less idiosyncratically distorted, often self-directed forms of normally social behavior. The results also illustrate that abnormal behavior patterns can be considered at different levels of integration which should be clearly distinguished in comparative studies. Similarities to the behavior of human mental patients suggest that social deprivation is a prominent factor in a wide variety of mental diseases.