Chromosome breakage in users of marihuana

Forty-nine users of marihuana (29 male and 20 female) and 20 control subjects (12 male and 8 female) were studied with peripheral blood lymphocyte cultures for the presence of chromosome breaks and abnormal forms. An average of 3.4 cells with breaks per 100 cells (range 0 to 8) were noted in the user group, and 1 to 2 cells with breaks per 100 cells (range 0 to 5) were noted in the control group. No significant differences were noted in chromosome breakage between "heavy" and "light" users, users of mixed drugs when compared to users of marihuana only, users of marihuana and caffeine when compared to marihuana users not using caffeine, and male and female users. There were increases in numbers of cells with abnormal chromosome configuration in users as compared to control subjects, but the numbers were too small to be significant. The possible significance of these data is discussed.