Insomnia is a major public health problem considering its high prevalence, impact
on daily life, co-morbidity with other disorders and societal costs. Cognitive behavioral
treatment for insomnia (CBTI) is currently considered to be the preferred treatment.
However, no meta-analysis exists of all studies using at least one component of CBTI
for insomnia, which also uses modern techniques to pool data and to analyze subgroups
of patients. We included 87 randomized controlled trials, comparing 118 treatments
(3724 patients) to non-treated controls (2579 patients). Overall, the interventions
had significant effects on: insomnia severity index (g = 0.98), sleep efficiency (g = 0.71),
Pittsburgh sleep quality index (g = 0.65), wake after sleep onset (g = 0.63) and sleep
onset latency (SOL; g = 0.57), number of awakenings (g = 0.29) and sleep quality (g = 0.40).
The smallest effect was on total sleep time (g = 0.16). Face-to-face treatments of
at least four sessions seem to be more effective than self-help interventions or face-to-face
interventions with fewer sessions. Otherwise the results seem to be quite robust (similar
for patients with or without comorbid disease, younger or older patients, using or
not using sleep medication). We conclude that CBTI, either its components or the full
package, is effective in the treatment of insomnia.