3. RESULTS: Sixty percent of these patients had depressive symptomatology. The severity of comorbidity (Charlson index) was 4 and the patient perception of quality of life (Short Form-12 scores) were between 79 and 82 The prevalence of non adherence was 70% even with a low MPR of 0.2. Insomnia patients with depressive symptoms were 92% less likely to be adherent to their insomnia medications (p0.05). After controlling other variables, we found MPR was good predictor of total health care costs (10% increase in MPR for every 2% decrease in total health care costs, p0.01)