The efficacy of Cognitive-Behavioural Therapy (CBT) as related to sleep quality and hyperarousal level in the treatment of primary insomnia.

BACKGROUND

Primary insomnia (PI) is a common sleep disorder affecting diurnal functioning. It may contribute to the development of several comorbidities such as major depression or arterial hypertension. It affects about 7% of the adult population. Pharmacotherapy remains the most common treatment for insomnia. However, many studies suggest CBT may be a supreme therapeutic approach resulting in a better long-term outcome. The aim of the study was to determine the efficacy of a CBT-protocol in the treatment of PI by means of sleep onset latency and the number of awakenings during night parameters along with sleep quality and the level of psychophysiological hyperarousal. The secondary outcomes were focused on CBT efficacy as determined by the predisposition to insomnia as related to higher vulnerability to stress (measured with FIRST) MATERIAL AND METHODS: Twenty-six individuals from a tertiary reference sleep disorders outpatients' clinic (22 women; mean age 41.4; 4 men; mean age 42.5) with primary insomnia (DSM-IV-TR) were included in the study. The exclusion covered other primary sleep disorders, secondary insomnia (psychiatric illness, unstable somatic illness, shift work), substance abuse/dependence, high results in HADS-M scale (score above 11). The participants were scored with HADS-M, Ford Insomnia Response to Stress Test (FIRST) at the beginning of the study. The Athens Insomnia Scale (AIS), Hyperarousal Scale, Leeds Sleep Questionnaire (LSEQ) were applied at the beginning, at the end and three months after the end of the study. The participants were also examined by 7 days actigraphic records before and after treatment. During the course of the treatment patients completed a Sleep Diary (SD). The CBT program employed was based on the Perlis protocol. Standard individual sessions of 50 minutes were provided on a weekly basis for 8-10 weeks by a board certified CBT therapist. After 3 months a follow-up session was scheduled.

RESULTS

The significant improvement as related to the CBT treatment was present in the measures of sleep onset latency (67.2 vs. 23.4 min.; p<0.000), numbers of awakenings during night (2 vs. 0.4; p<0.000) and sleep efficiency (77.3 vs. 91%; p<0.000) - data from SD, quality of falling asleep (3.2 vs. 6; p<0.000), quality of sleep (3.3 vs. 5.8; p<0.000) and quality of morning awakening (3.2 vs. 6; p<0.000) - data from LSEQ. The improvement reached the significance level in the measure of psychophysiological arousal (52.3 vs. 42.4; p<0.000) and AIS (15.7vs. 6.8; p<0.000). No significant differences were identified between actigraphic records (light/dark ratio) before and after CBT. FIRST scores allocating patients to high and low stress vulnerability groups were non-contributory to the observed treatment efficacy.

CONCLUSION

CBT is an effective treatment in primary insomnia. No relationship between CBT efficacy and predisposition to insomnia as determined by higher vulnerability to stress was identified.