Are dysfunctional attitudes and beliefs about sleep unique to primary insomnia?

Dysfunctional thinking about sleep is a central aspect in the perpetuation of primary insomnia and a target symptom of cognitive behavioral therapy for insomnia (CBT-I). Insomnia symptoms also occur in other sleep disorders, but it is not known to what extent it is related to dysfunctional thinking about sleep.

The Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS) was administered to inpatients at a sleep center. The following groups were included: 34 patients with primary insomnia (PI), 30 patients with sleep apnea syndrome (SAS), 31 patients with restless legs syndrome (RLS), 26 patients with SAS comorbid with RLS (SAS + RLS), and 24 patients with idiopathic hypersomnia or narcolepsy. Eighty-four healthy subjects served as a control group. The DBAS scores were compared across the different sleep disorders and correlated with polysomnographic (PSG) variables, subjective sleep parameters, scores of the Beck Depression Inventory (BDI), and the Regensburg Insomnia Scale (RIS; measuring psychological symptoms of insomnia).

Compared to healthy controls, DBAS scores were increased in PI, RLS and RLS + SAS. There was a low correlation between DBAS scores and PSG variables, moderate correlations between DBAS and subjective sleep parameters and BDI scores (r = 0.528), and a high correlation between DBAS and the RIS score (r = 0.603).

The observation of increased DBAS scores in other sleep disorders besides primary insomnia underscores the usefulness of a broadened diagnostic procedure and suggests that CBT-I modules may be a complementary treatment tool for these disorders.