CBT-Based Group Intervention for Insomnia - A Non-Randomized Trial in Primary Care

Insomnia is a major health problem, commonly leading to pharmacological treatment. During recent years, behavioural therapies have gained stronger therapeutic position, not least cognitive behavioural therapy (CBT). The aim was to investigate the effect of a CBT-based group intervention for insomnia in primary care, by means of self-reported sleep quality and duration. In addition, cortisol in saliva, as a biological marker of stress was tested. Methods: Fifty participants with primary insomnia, attending primary care, were enrolled, 35 receiving the intervention, and 15 serving as control. The intervention group was recruited during the first two study years, and controls during a following third year, without randomization. The intervention included eight CBT-based group sessions, each two-hour long and led by a psychologist, with 4-6 participants in each group. Controls were handled in accordance with ordinary clinical routine, including pharmacological intervention. Sleep onset time, duration and quality were assessed before and after the intervention, by patients filling-out the Pittsburgh Sleep Quality Index (PSQI). Insomnia severity was assessed by the Insomnia Severity Index (ISI). Also, cortisol in saliva levels were monitored. Results: In the intervention group, significant shortening of mean sleep onset time, from 60-27 min (p<0.05) was observed, and a prolongation of mean sleep duration time, from 298-358 min (p<0.05), in neither case seen in the control group, although between-group difference was not statistically significant. Both PSQI and ISI means scores were significantly improved in the intervention group, from 12.1 to 7.9 (p<0.05) and from 19.4 to 12.5 (p<0.01), respectively, in the latter case significantly more so than in the control group (p<0.05). No effect on cortisol levels was detected, in either group. In conclusion, the tested eight-session CBT-based group intervention for insomnia appears to reduce severity and duration of insomnia, and to shorten time before falling asleep, when provided in primary care.