The prescriptions for psychoactive drugs presented to the Health Insurance system for reimbursement of charges are a source of information about some psychological illnesses and disorders in the context of the overuse of these drugs in France. In Nord - Pas-de-Calais Region, out of a total of 5 070 160 prescriptions in 2007, 576 493 individuals benefited from at least one such drug. Over the period of the study, 15.6% of the population of the region covered took at least one psychotropic medication. The rate of use was 11.7% for benzodiazepines, 7.6% for anti-depressants, 1.8% for anti-psychotics, 0.5% for treatment of alcohol dependence and 0.3% for opiate substitution therapy (OST). For the first three of these classes rate of use increased steadily with age. It was invariably much higher in women than in men. Men were treated more frequently for alcoholism and heroin dependency; the proportion taking medication initially increased with age (up to 40-49 years for alcohol dependency and 30-39 years for OST), before falling thereafter.