Global sleep dissatisfaction for the assessment of insomnia severity in the general population of Portugal.

BACKGROUND AND PURPOSE

This study examines the prevalence and associated factors of insomnia symptoms and sleep dissatisfaction in the general population of Portugal.

PATIENTS AND METHODS

We interviewed by telephone 1858 participants aged 18 years or older and representative of the general population of Portugal using the Sleep-EVAL system. Participation rate was 83%. The questionnaire included the assessment of sleep habits, insomnia symptomatology according to DSM-IV and ICSD classifications, associated and sleep/mental disorders and daytime consequences.

RESULTS

Insomnia symptoms occurring at least 3 nights per week were reported by 28.1% of the sample and global sleep dissatisfaction (GSD) by 10.1%. Difficulty maintaining sleep was the most frequent symptom (21.0%); 29.4% of subjects with insomnia symptoms reported GSD. Daytime consequences, medical consultations for sleep and use of sleep medication were at least 2 times more frequent among subjects with insomnia symptoms and GSD compared to subjects with insomnia symptoms without GSD; insomnia diagnoses were also more frequent in the GSD group.

CONCLUSIONS

The results show a severity gradation among subjects with only 1 insomnia symptom, those with 2 or 3 insomnia symptoms but without GSD and those with at least 1 insomnia symptom and GSD. Specific sleep or psychiatric disorders were identified for the majority of GSD subjects (86%); this rate dropped to 50.6% when only 1 insomnia symptom without GSD was reported. GSD appeared to be a good indicator of the presence of a sleep or psychiatric disorder and a good discriminator of the severity of sleep disturbances among subjects with insomnia symptoms.