SOCIAL-FACTORS AND COMORBIDITY OF DEPRESSIVE AND ANXIETY DISORDERS

Differences in rates of depression across and between populations can be considerable and are largely determined by psychosocial factors, Su ch findings have important implications for comorbidity. On the basis of multiplying independent probabilities, the proportion of comorbid c onditions increases as base rates of the disorders increase in a popul ation. if such a chance combination has clinical implications, it woul d appear to be a ''fact'' of significance irrespective of biological u nderpinnings. In a recent survey of 404 women living with ar least one child in an inner-city area, the rate of both anxiety and depression was highly related to the childhood experiences of neglect and abuse. However, adversity in adult life (e.g. widowhood or divorce), which mi ght be expected to relate to current stressors, was-only related to th e rate of depression. The hive risk factors had a considerable impact on comorbidity by increasing the rate of each disorder and thus the pr obability of their occurring together. They had a lesser impact as com mon antecedents: If both influences are considered, such adversity exp lains around half of the comorbidity. This is a conservative estimate of the impact of psychosocial factors.