Abstract
Background: Drug abusing is a worldwide major cause of preventable morbidity and mortality. Substance abusing affects the cardiovascular system by several mechanisms.

Aims and Objectives: The objective of the present study was to study the effect of drugs on the cardiovascular autonomic functions among different drug abusers and also to identify early neurological damage in autonomic system so that proper counseling and timely intervention can be undertaken.

Materials and Methods: This cross-sectional study was done at GGS Medical College, Faridkot, Punjab, during the period from August 2012 to July 2013 in 50 drug abusers within the age group of 15-45 years, as well as in age matched 50 healthy controls. The subjects were recruited from Faridkot region of Punjab which included subjects from general population and the patients admitted in Drug De-addiction Centre of GGS Medical College and Hospital, Faridkot, Punjab. Prior informed written consents were obtained from them after explaining to them, the procedure and the purpose of the study tests. Lying to standing test was carried out for assessing parasympathetic reactivity and hand grip test for sympathetic reactivity.

Results: After applying the ‘t’ test for the difference between the two sample means, it was observed that there was a highly significant difference between the mean values of the parasympathetic function tests among the drug abusers and the controls (i.e., P < 0.001). The 30:15 ratio (response to standing) had significantly decreased in the drug abusers as compared to those in the controls. Also a highly significant difference was observed between the mean values of the sustained handgrip test in the drug abusers and controls (i.e., P < 0.001).

Conclusion: This study provides good evidence for autonomic dysfunction following chronic abuse of different drugs. By using these simple tests, we can detect the early involvement of the autonomic nervous system before the clinically related symptoms appear and they are thus useful in taking steps to prevent the further progress of the disease.

Key words: Autonomic Function Tests; Hand Grip Test; Lying to Standing Test; Substance Abuse