Effect of alcohol and Cannabis sativa consumption on handwriting

This study reports on the separate effect of Cannabis sativa smoking and of alcohol consumption on handwriting performance in Cannabis users and in alcoholic volunteers, respectively. Handwriting samples were obtained prior to, during, and after 1 hr of Cannabis or alcohol consumption. Handwriting was evaluated for speed, letter forms, size, slant, and alignment. Cannabis sativa smoking exerted greater effect on handwriting than did alcohol drinking. This effect was noted during Cannabis smoking and lasted for 1 hr thereafter. Changes noted in handwriting performance test, which reflect involuntary muscular movement and tremor, suggest a differential CNS depressant action of the compounds used under the experimental trials listed. The results suggest possible forensic application, i.e., the use of handwriting for the purpose of signature comparison obtained under the influence of alcohol or under Cannabis intoxication.