Background: The number of newly reported psychoactive substances in Europe is now higher than ever. In order to evade legal restrictions, old and novel psychoactive substances from medical research and their derivatives are commonly mislabeled as "not for human consumption" and offered for sale on the Internet and elsewhere. Such substances are widely taken by young people as "club drugs." Their consumption must be considered in the differential diagnosis of psychiatric, neurological, cardiovascular, or metabolic disturbances of unclear origin in a young patient.
Method: Selective review of pertinent literature retrieved by a PubMed search, including publications by government-sponsored organizations.
Results: From 2010 to 2012, 163 substances were reported to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), mostly either synthetic cannabinoids (39.3%) or synthetic cathinones (16.6%). Synthetic cannabinoids alter mood and perception; intoxications cause agitation, tachy cardia, and arterial hypertension. Synthetic cathinones are hallucinogenic stimulants with predominantly cardiovascular and psychiatric side effects. Severe intoxications cause serotonin syndrome and potentially fatal rhabdomyolysis. Substances in either of these classes often escape detection in screening tests.
Conclusion: Young persons who present with agitation and cardiovascular and/or psychiatric manifestations of unclear origin and whose drug screening tests are negative may be suffering from an intoxication with a novel psychoactive substance. Physicians should know the classes of such substances and their effects. Targeted toxicological analysis can be carried out in a toxicology laboratory or a facility for forensic medicine.