The usage of psychotropic substances constitutes a major public health concern due to its association with the risk of sexually transmitted infections. This study examines the prevalence of venereal diseases in patients who misuse illicit drugs at the Federal Neuropsychiatric Hospital (FNPH) in Kaduna, Nigeria. A cross-sectional study was conducted in which data were collected from people aged 16 to 45 years by structured questionnaires, blood samples, and urine analysis. A laboratory examination was performed to detect antibodies to HBV, HCV, VDRL, and HIV using fast assays. The findings revealed that the age group most affected was 20-29 years, with a higher frequency among males than females. Among the identified venereal illnesses, HBV was the most prevalent, succeeded by HCV, VDRL, and HIV. Co-infection primarily occurred between HBV and HCV. The research indicates the necessity for coordinated healthcare programs that tackle substance abuse and sexually transmitted infections. Harm reduction initiatives, such as safe injection sites and comprehensive sex education, should be accessible to alleviate the health repercussions of substance usage.