Sleep Beliefs, Subjective Sleep Quality and Diurnal Preference - Findings from Depressed Patients

Article excerpt

Abstract

This study evaluated the relationship between dysfunctional sleep beliefs, circadian typology and self-reported sleep quality and insomnia. We assessed these parameters both in healthy controls and patients with depression. One hundred eighty six subjects were assessed and completed measures of sleep beliefs, sleep disturbance, sleep quality, daytime sleepiness, depressive symptoms and circadian typology. We found that sleep beliefs are slightly linked with the subjective sleep quality, but with neither the diurnal preference, nor the self-reported insomnia.

Keywords: sleep quality, sleep beliefs, diurnal preferences, depression

In modern society, sleep problems are common, occurring in up to a third of the general population worldwide (Ohayon, 2002). Several risk factors for poor sleep quality have been identified, amongst which are: sleep hygiene and dysfunctional attitudes and beliefs towards sleep (Ohayon, 2002; Roth, 2007). It has been reported that more positive sleep beliefs and attitudes are associated with better sleep quality (Brown, Buboltz, & Soper, 2002; Gellis & Lichstein, 2009; Jansson & Linton, 2007; Morin, Blais, & Savard, 2002). However, insomniacs show superior appreciation of sleep hygiene, but still maintain poorer sleep practices than good sleepers (Carney, Edinger, Manber, Garson, & Segal, 2007; Gallasch & Gradisar, 2007; Gellis & Lichstein, 2009; Kohn & Espie, 2005). It has been hypothesized that poor sleepers either do not find sleep hygiene useful, or do not persist with it (Gallasch & Gradisar, 2007). Further, poor sleepers display higher levels of mental arousal, itself a known risk factor for insomnia (Kohn & Espie, 2005).

Other attempts to reveal risk factors for insomnia have focused on individual differences, such as age, gender, marital status, income, education and occupational status (Ohayon, 2002). One such factor that has been shown to significantly influence sleep quality is diurnal preference, the attribute of the human circadian system determining whether individuals are optimally alert and active early or late in the day (Chung, Chang, Yang, Kuo, & Hsu, 2009; Mongrain, Carrier, & Dumont, 2005; Taillard, Philip, & Bioulac, 1999). Recently, an international study revealed that diurnal preference influences sleep hygiene, as those with an evening orientation display more maladaptive sleep beliefs (Adan, Fabbri, Natale, & Prat, 2006). However, the relationship between chronotype and sleep beliefs has only been studied on the healthy population, with no data available to date on the potential influence of disease on this interplay.

Sleep disturbance is a symptom of many medical or psychiatric disorders, being a classic finding in the assessment of the depression. There is strong evidence that pre-existing insomnia contributes greatly to the course and severity of depressive disorders and even predicts relapse or poor outcome (Franzen & Buysse, 2008; Srinivasan, et al., 2009). The management of insomnia has been dramatically affected by the understanding of its psychopathogenesis, such that, currently, first line treatments are cognitive and behavioral interventions, with pharmacotherapy representing a second line approach.

The detection of the dysfunctional sleep beliefs, together with assessing behaviors inconducive to sleep, might help in better understanding the role of sleep beliefs and sleep hygiene in relation to insomnia. This study focuses on evaluating the relation between dysfunctional sleep beliefs, diurnal preference, subjective sleep quality and self-reported insomnia in depressed patients compared to healthy controls. We hypothesized that dysfunctional sleep beliefs would be more prevalent among the poor sleepers and evening chronotypes.

Method

Participants

The study was approved by the Ethics Committee of "Iuliu HaEieganu" Medicine and Pharmacy University, Cluj-Napoca, Romania. …