Cross-sectional analyses of factors associated with the presence and aggravation of chronic insomnia by symptom subtypes.

Aim: The aim of this study was to investigate the association of psychological and chronobiological factors with the presence and severity of chronic insomnia by symptom subtypes and their impacts on daytime dysfunctions.

Methods: Participants of the present web-based epidemiological study were classified as follows: difficulty initiating sleep (DIS) ( = 91); difficulty maintaining sleep (DMS) ( = 13); early morning awakening (EMA) ( = 48); DIS + DMS ( = 67); DIS + EMA ( = 23); DMS + EMA ( = 24); triplet of DIS, DMS, and EMA symptoms (TRP) ( = 69); and normal sleepers ( = 4590). The Insomnia Severity Index (ISI), Hospital Anxiety and Depression Scale (HADS), Munich Chronotype Questionnaire (MCTQ), insomnia-related psychological measures (including the Ford Insomnia Response to Stress Test [FIRST] and the Dysfunctional Beliefs and Attitudes about Sleep Scale [DBAS]), and the cognitive and somatic domains of the Pre-Sleep Arousal Scale (PSAS) were evaluated.