Interpersonal sensitivity predicts depressive symptom response to the circadian rhythm disruption of nightwork

This paper reports the results of a study designed to explore the validity of a shiftwork model of affective disorders. Fifty-five student nurses doing nightwork for the first time were recruited to a study designed both to replicate an earlier study of the effects of nightwork on cognitive, emotional and neurovegetative measures and to assess the effects of nightwork on personality measures and the role of personality factors and nightwork induced disturbances in predicting accommodation to nightwork. As in the earlier study, concentration, interest, energy, sleep and appetite were significantly disturbed by nightwork and there was an increased perception of recent criticism from others. The findings from both studies were, therefore, aggregated to explore further possible relations between outcomes and the pre-nightwork level of affective symptoms and sensitivity to interpersonal criticism. These predicted poor response. In contrast, measures of cognitive style and symptom interpretation did not predict outcome. The findings are not inconsistent with proposals that disturbance of circadian rhythms consequent on psychosocial disruptions may play a part in the genesis of or maintenance of depression. They also support a proposal that nightwork induced changes may be a suitable human model for investigation of aspects of the affective disorders.