Depressive symptoms in patients with hypersomnia measured with Beck Depression Inventory

Patients with central hypersomnia (HCO) often show symptoms of depression. Despite of many studies conducted in this field, the link between these two disorders remains unclear. In order to contribute data to this research, we examined the question of which depressive symptoms characterize these patients. Furthermore, we investigated the differences between HCO who were more or less depressed regarding insomnia, sleep quality and daytime tiredness.

The retrospective analysis assesses the presence and kind of depressive symptoms as measured by the Beck Depression Inventory (BDI) in 168 HCO including narcolepsy type I (NAR1), narcolepsy type II (NAR2) and idiopathic hypersomnia (HYP). Sleep parameters from one night of polysomnography, scores of questionnaires for insomnia and for daytime sleepiness, and data from sustained attention tests were compared between HCO with and without depression, as determined by BDI scores (cut off >12).

According to BDI scores 52% exhibited no depression. The BDI items pertaining to tiredness and work inhibition exhibited elevated scores, whereas those pertaining to suicidality showed low scores. No difference was found between depressed and non-depressed HCO with regard to daytime vigilance performance or daytime sleepiness. However, depression was associated with older age, higher insomnia scores, and a shorter sleep time on polysomnography.

A potential interpretation of our findings is that depressive symptoms in HCO may be a consequence of restricted life quality due to hypersomnia. Thus, therapeutical effort should focus more intensely on coping strategies.