Self-Reported Adverse Events in Psychiatric Outpatients Taking Hypnotics: Higher Real-World Frequencies Than Those Listed in Package Inserts

Introduction: Benzodiazepines (BZDs) are associated with dependence, tolerance, withdrawal, and various adverse effects, and switching to other drug classes is often recommended. Although non-BZD hypnotics are reported in package inserts to have similar but less frequent adverse events, real-world patients often have complex psychiatric and medical backgrounds, and the actual frequency of subjective adverse events may differ substantially from that reported in package inserts. This study aimed to elucidate subjective symptoms potentially related to psychotropic medications using real-world patient data. Methods: This prospective cohort study included patients at the Akebono Clinic who were taking a single hypnotic agent. A total of 314 patients were analyzed. Insomnia severity was assessed using the Athens Insomnia Scale, and 11 self-reported adverse events were evaluated. Results: The frequency of insomnia was 72% for non-BZDs, 52% for BZDs, and 70% for dual orexin receptor antagonists (DORAs) (significantly lower for BZDs; p = 0.0036). Among the 11 self-reported symptoms, two items (thirst and nightmares) were reported as “always” or “often” by more than 10% of patients; three items (constipation, head heaviness/headache, and abnormal behavior during sleep) by 5%–10%; and four items (lightheadedness, vertigo, abdominal pain, and tremor) by 3%–5%. There were no differences in adverse-event frequencies among non-BZDs, BZDs, and DORAs. Multivariate analyses showed that adverse events were associated with female sex, age < 60 years, and schizophrenia, depression, and anxiety disorders, but not with hypnotic drug classes. Conclusions: Subjective adverse events in patients taking hypnotics occurred more frequently than those reported in package inserts, indicating a clear discrepancy between controlled trial data and real-world clinical experience. Because adverse events were more strongly associated with patient characteristics—such as psychiatric comorbidities, physical conditions, and concomitant medications—than with hypnotic drug class, routine assessment of subjective symptoms through interviews or questionnaires is essential in clinical practice.