Chronic insomnia (ChI) is a common condition in Primary Care (PC). Regardless that it's often related to psychiatric morbidity it appears to be a strong predictor of future depression and a disabling disorder by itself. The aim of this study was to measure and compare clinical and psychiatric characteristics of both patients with primary ChI and secondary ChI.

A random sample of 225 subjects older than 18 years old, from 3 PC Centres of the area of Madrid (Spain) was interviewed using the Oviedo Sleep Questionnaire, a semi-structured interview for sleep disorders. The subjects completed the Patient Health Questionnaire. Data about medical conditions, drug treatments, days of work lost (last year) and use of health care services (last 3 months), were also collected. Psychiatric and clinical characteristics between groups (primary vs secondary ChI) were compared.

78 patients fulfilled criteria for ChI and 53 (67.9 %) of them were suffering from any psychiatric disorder (including subtreshold conditions). Patients with primary ChI compared to secondary insomnia patients had no significant differences in age, gender, use of health care resources and days of work lost. However, patients with secondary ChI compared to primary ChI had more somatic and depressive symptoms (U-Mann-Witney test; p=0.002 and p<0.001, respectively).

There is an important group of patients among PC attendees suffering primary ChI. Patients suffering primary ChI are comparable to patients with psychiatric disorders and insomnia in terms of days of work lost and use of health care resources.