The diagnostic and therapeutic value of time in bed extension in Insufficient Sleep Syndrome.

Background: Insufficient sleep syndrome (ISS) represents an emerging health concern but remains poorly defined as a diagnostic entity, though included in the international classification of sleep disorders. In the present study, we aimed to clarify the longitudinal course of ISS and to identify prognostic factors by comparing remitting and non-remitting patients.

Methods: A chart-review was realized, retrieving fifty-five patients with ISS (aged 39.8 ± 16.6 years, with 44.6 % of women) who underwent a comprehensive clinical evaluation at baseline and during a follow-up visit after 3-6 months. This evaluation included sleep symptoms, sleep logs, medications, and comorbidities. Additionally, actigraphy, video-polysomnography, and a multiple sleep latency test were conducted at baseline, and at the same moment standard psychoeducation on sleep was provided.

Results: During the follow-up visit, 69 % of patients still met the criteria for a clinical diagnosis of ISS, experiencing symptoms such as daytime sleepiness, disrupted nighttime sleep, unrefreshing sleep, and sleep attacks. Comparing sleep patterns of remitters and non-remitters based on sleep diaries, we observed that remission is associated with not only an increase in total sleep time but also a more regular sleep schedule. This regularity includes a reduction in napping and a lesser difference in sleep timings between weekdays and weekends. However, comparing baseline clinical and instrumental data between remitters and non-remitters revealed no significant differences, hindering the use of these features as prognostic factors.

Conclusions: Given the low remission rate with standard treatment (i.e. psychoeducation on sleep), we propose the following: (1) Criterion E (extension of total sleep time results in resolution of the symptoms of sleepiness) should be considered as a therapeutic advice, and supportive rather than necessary for the diagnosis; (2) specific cognitive-behavioral therapy protocols targeting the cognitive factors underlying sleep-depriving behaviors are required, as single routine behavioral interventions are insufficient.