The primary objective of the study is to establish the link between drug use and the onset of schizophrenia. Materials and methods. We have studied 60 patients diagnosed with schizophrenia in the Am Waldsee Clinic, Riedener Muehlen, Germany, who are also consumers of illicit drugs. The study was conducted in 2011-2014. We conducted a cross-sectional study, the main parameters studied being the type of drug used, the age at which patients started to use drugs and age of onset of schizophrenia. Results: In our study group men predominated, male/female ratio being 1.9: 1, the average age was 25.9 years, and most of the patients were from urban areas. The most used drugs were cannabis (91,67%) and amphetamines (85.00%). Cocaine and ecstasy were consumed by over 50% of subjects (51.67% and 53.33%). We noted that only 11.67% of the cases had consumed one drug. Over 75% of the subjects began drug use at ages under 15 years. Onset of schizophrenia was 55% of subjects aged below 20 years old. Conclusions: The onset of illicit drug use starts at very young ages, under 15, the most widely used drugs are cannabis and amphetamines. The younger the onset of drug use, the earlier the age of schizophrenia onset.