[The Zung's autoscale for depression as predictor of sensorial and autonomic alterations to pain]

Abstract

Clinical and experimental evidence support a relationship between susceptibility to chronic pain and a subjacent depression. Nevertheless, it's not clear if the currently available clinical evaluation instruments for depression allow for linking both disorders. Thus, we evaluated a Zung's autoscale for depression and its different categories: affective, physiological, motor and psychological, as possible predictors of sensorial and autonomic alterations and vulnerability to clinical chronic pain. In 32 healthy controls and 11 subjects with minor depression and free of treatment, ischemic pain was first induced by applying a tourniquet on the dominant arm, and then followed by paresthesias during the reperfusion of arm as the tourniquet is released. Ischemic muscular pain, post-ischemic paresthesias and associated cardiovascular responses were recorded throughout the experimental procedure. The affective category's score was correlated linearly in individual form with the greatest number of variables and it was adjusted to a model of multiple regressions that almost explained the variance in 100% with a contribution of the sensorial and autonomic variables of a 70% and 30%, respectively. In addition, the affective category was 50% greater in subjects with persistent clinical pain. The Zung's index and the other categories had a smaller number of individual linear correlations and models of multiple correlations that only explained between 30-70% of the variance, with a more predominant contribution of the autonomic variables (20-50%), especially in the psychological category. This suggests that the affective category predicts cutaneous-muscular sensorial alterations with greater effectiveness than the Zung's total index.