This research aims to summarize and discuss issues related to psychiatric drugs by using the classification system of the Pharmaceutical Care Network Europe (PCNE) and to provide a reference for the development and direction of clinical pharmacists’ work in the future. Psychiatric patients who were hospitalized in our hospital from Janurary 2023 to December 2023 were enrolled. Drug-related problems (DRPs) were evaluated using the PCNE classification system (version 9.0). The types, causes, intervention plans, acceptance of intervention plans, and statuses of DRPs were analyzed. A total of 362 patients were included, covering 405 DRP cases, with an average DRP of 1.12 for each patient. All 405 DRP cases underwent interventions, with a success rate of 83.46%. The main categories of related drugs were psychotropic drugs (70.37%), anti-infective drugs (8.89%), and cardiovascular system drugs (5.19%). The main DRPs were possible adverse drug events (21.24%), poor treatment effects (69.14%), and unnecessary medication treatment (9.63%). The main causes of DRPs were inappropriate drug selection (18.52%), inappropriate combinations of drugs (16.05%), and excessive drug dosage (13.58%). The PCNE classification system helps clinical pharmacists improve their ability to identify and solve DRPs faced by psychiatric departments, improve pharmaceutical care efficiency, and ensure rational drug use.