Abstract
Cognitive behavioral treatment is the gold standard treatment for insomnia, although a substantial group does not respond. We examined possible predictors for treatment outcome in psychophysiological insomniacs, with a focus on the presence of clearly defined psychiatric comorbidity. This was a longitudinal uncontrolled case series study comprising 60 patients with chronic psychophysiological insomnia consecutively referred to a tertiary sleep medicine center, to receive cognitive behavioral treatment for insomnia (CBT-I). Remission of insomnia was defined as a posttreatment Insomnia Severity Index score below 8. As an alternative outcome, we used a clinically relevant decrease on the Insomnia Severity Index (drop of > 7 points). Personality, coping, and social support questionnaires were assessed before the start of the treatment and were compared between treatment responders and nonresponders. To examine whether these variables were predictive for negative treatment outcome, logistic regression analyses were applied. Treatment nonresponders had a significantly higher prevalence of psychiatric comorbidity. Logistic regression analyses showed that the presence of psychiatric comorbidity was strongly predictive for negative treatment outcome (odds ratios: 20.6 and 10.3 for the 2 outcome definitions). Additionally, higher scores on the cognitive coping strategy called "refocus on planning" were associated with worse CBT-I outcome. Current psychiatric comorbidity is strongly predictive for negative treatment outcome. The presence of a psychiatric disorder must therefore be one of the leading arguments in the choice of treatment modalities that are being proposed to patients with insomnia.
