Subjective symptoms and objective measures in idiopathic hypersomnia and hypersomnia associated with psychiatric disorders: a prospective cross-sectional study.

STUDY OBJECTIVES In some cases, it is difficult to correctly nosologically classify daytime sleepiness. Clinical manifestations may be non-specific, on the basis of objective measures it is possible to determine the current severity of sleepiness, but they do not always allow accurate diagnosis. It is especially difficult to distinguish between idiopathic hypersomnia (IH) and hypersomnia associated with a psychiatric disorder (PSY). METHODS In order to find significant differences between the IH and PSY groups, we included 67 patients (IH, n=15; PSY, n=52) in the study, focusing on differences in subjective symptoms, evaluating current depressivity using the BDI-II score and personality traits measured by TCI. All of the subjects underwent polysomnography, MSLT and ad libitum sleep monitoring. RESULTS The IH patients showed greater difficulty with waking up in the morning (p < 0.001) and complained of memory (p = 0.04) and attention deficit (p = 0.006). They also showed higher total sleep time (p < 0.001), sleep efficiency (p = 0.007) and a shorter MSLT mean latencies (p < 0.001). Nevertheless, the IH and PSY groups did not differ in BDI scores or personality characteristics. CONCLUSIONS IH is a syndrome in which depression/external life stressors and personality characteristics also play a role. IH patients may benefit from the cooperation of sleep specialists with psychotherapists/psychiatrists.