A multidisciplinary biopsychosocial approach reveals behavioural phenotypes in idiopathic hypersomnia: a prospective single-arm study.

Idiopathic hypersomnia (IH) is clinically heterogeneous yet defined almost entirely in electrophysiological terms, and pharmacotherapy frequently fails to restore daytime functioning. We asked whether IH heterogeneity extends to stable behavioural phenotypes and whether an individualised, multidisciplinary, non-pharmacological programme is feasible and yields a clinically meaningful signal on symptom burden. In this prospective single-arm study, 20 adults with ICSD-3-TR-diagnosed IH at a tertiary sleep centre completed a programme combining psychoeducation, cognitive-behavioural therapy for hypersomnia (CBT-H), and psychosomatic physiotherapy. The pre-specified primary outcome was the Idiopathic Hypersomnia Severity Scale (IHSS); secondary outcomes were the Epworth Sleepiness Scale (ESS), Sleep Inertia Questionnaire (SIQ), and Beck Depression and Anxiety Inventories. Behavioural phenotypes were derived by thematic analysis. The programme was feasible; all completed it and wished to continue. IHSS decreased from 33.5 (SD 4.2) to 27.5 (SD 5.3) (mean reduction 6.0 points, 95% CI 4.5-7.5; dz = 1.85; p < .001), exceeding the 4-point minimal clinically important difference, concentrated in the daytime-functioning items. ESS fell more modestly (17.8 to 13.9; dz = 0.80; p = .002), remaining pathological, while sleep inertia, depression, and anxiety changed little. Thematic analysis identified two recurrent phenotypes-a hyperactive, overachieving profile and a withdrawn, inhibited profile-differing in interest in psychostimulants; interest was confined to the 9 of 20 with diagnosed or suspected ADHD. A biopsychosocial programme is feasible and associated with clinically meaningful improvement in daytime functioning rather than core sleepiness, and reveals stable behavioural phenotypes that may inform personalised care. Controlled trials are warranted.