0525 Subtypes of Efficacy of Cognitive-Behavioral Therapy for Insomnia

Introduction Cognitive-Behavioral Therapy for Insomnia (CBT-I) is the first-line treatment for Insomnia disorder (ID). We aimed to identify ID patients’ subtypes based on clinical features and their response to CBT-I. Methods 294 chronic insomnia patients (61.6% female, mean age 40.7 ± 12.3 yrs) underwent 7-sessions group CBT-I. By use of latent class analysis (LCA) we identified insomnia disorder subtypes according to baseline (BL) evaluation of non-sleep indices and the response to CBT-I (Delta score of Insomnia Severity Index ISI between BL and end-of-treatment (ET). Moreover, we assessed ISI in 123 out of 294 insomnia patients (82 females (66.7%), mean age 40.59 ± 11.89 years) who completed a follow-up evaluation (FU) within a range of 4-10 years. Results We chose 3 latent classes as most parsimonious model. We identified Class 1 (insomnia+anxiety+depression+stress) (n=62), Class 2 (insomnia+anxiety+depression) (n=153) and Class 3 (only-insomnia) (n=79). The effect of CBT-I was maintained up to 10 years after the ET in the three classes but with significant difference between classes (p<0.05). At the ET, the largest percentage of responders (ISI decrease ≥ 8) was found in Class 1 (63.5%). Results of overall CBT-I effectiveness: in Class 3, 98.6% had subthreshold insomnia (ISI score=0-14) at the ET, and 97.2% at the FU; in Class 2, 89.0% at the ET, and 78.2% at the FU; in Class 1, 80.7% at ET and 51.8% at the FU. Conclusion Our analysis identified three different subtypes of insomniacs on the basis of clinical outcomes. The presence of anxiety and depression did not diminish the effect of CBT-I both short and long term. However, ID patients characterized by the presence of stress (Class 1) were the best responders at the ET but this was not maintained at the FU evaluation. We can speculate that stress could be considered a risk factor that plays an important role in the long-term outcome of CBT-I. Support No