Abstract
The use of psychoactive substances, whether occasional or regular, can induce a large number of clinical and/or biological complications. These complications may be related to the effects of the active substance itself and/or adulterants, but also to the modalities for use (administrations route, contexts of use). The detection and evaluation of these potentially severe complications are a public health issue. Beyond the assessment of the potential for abuse of and dependence on psychoactive substances, the collection and evaluation of complications related to the use of the substances are one of the roles of addictovigilance centres. In this article, the expertise of the French addictovigilance centres in the detection and assessment of medical complications related to psychoactive substances, adulterants or route of administration of substances is advanced through a few recent examples.