imConsultation Request Types and Clinical Implications for Insomnia in Inpatients: A Comparative Study With Anxiety and Depressive Disorders

Objective: Insomnia is one of the most common psychiatric symptoms among inpatients, frequently accompanied by sleep–wake and circadian disruption and showing distinct consultation patterns. This study aimed to examine the consultation request patterns and clinical implications of insomnia in hospitalized patients, and to compare them with those of patients with anxiety and depressive disorders. Methods: A retrospective chart review was conducted for 1,286 patients who received psychiatric consultations at a general hospital between 2005 and 2011. The sample included 236 patients with insomnia, 601 with anxiety disorders, and 449 with depressive disorders based on DSM-IV-TR criteria. Demographic characteristics, referring departments, reconsultation status, number of consultations, and consultation request types (CR1–CR5, based on the Vaz-Salcedo functional model) were analyzed. Results: Patients with insomnia were especially older and had a higher proportion of males compared with the other diagnostic groups. The insomnia group showed the lowest mean number of consultations and the lowest reconsultation rate. More than half of consultation requests for insomnia patients were classified as CR3 (Mending type), a proportion more than twice that observed in the anxiety disorder group. After adjustment for age and sex, insomnia remained independently associated with a significantly higher likelihood of CR3 consultation requests. Conclusion: Insomnia in hospitalized patients exhibits distinct consultation-liaison patterns, with a predominance of CR3, indicating a largely symptom-oriented management approach. Future multicenter, prospective studies with longitudinal follow-up are needed to evaluate the effectiveness of pharmacological and non-pharmacological interventions and to clarify the impact of early insomnia-focused psychiatric consultation on long-term clinical outcomes.