Cognitive and biochemical processes in depressed adult outpatients: a testof the circular process model

The circular process model is a psychobiological model of depression. in wh ich it is postulated that catecholamines and negative cognitions interact t o influence depression. Since its publication, there have been no empirical tests to support or refute the model. This study tested the model in 92 de pressed adult outpatients with non-bipolar non-psychotic depression. There were no significant bivariate correlations among the biochemical and cognit ive measures. However, the interactive model was supported by results of tw o out of three hierarchical regression analyses, in which the biochemical-b y-cognitive interactive terms significantly predicted depression after the main effects of each variable were accounted for. These findings show suffi cient evidence in support of the Circular Process Model to warrant further testing over the treatment period. (C) 2001 Elsevier Science Ltd. All right s reserved.