Background: Economic evaluations of generalized anxiety disorder (GAD) have been limited to ≤18 months. A decision model was developed; quantifying the lifetime cost-of-illness (COI) of GAD. Methods: An incidence-based Markov-model was developed using TreeAge® software, reflecting 9 health-states (HS): physician-assessed patients (3HS), maintenance therapies(4HS), discontinuation(1HS) and death(1HS). Onset probability (ages 18-80) determined model entry. Canadian Psychiatric Association (CPA) guidelines determined pharmaco-therapy, with revisions/validation by an expert panel. Response, remission based on pooled-analysis of CPA-cited evidence. Remaining clinical rates, absenteeism and hospitalization retrieved from literature. Direct (clinician, pharmacotherapy, hospitalization) and indirect costs (wage rate) retrieved from government publications. Results discounted at 5%. Results: The mean COI was 2008 Canadian $31,213(SD=$9,100)/patient; 96% attributed to absenteeism. Mean age=31years, discontinued treatment=85% by 2nd year, treatment discontinuation duration, 14(SD=9) years. CONCLUSION: GAD is a costly disease with a lifetime COI<$32k/patient; absenteeism exerts a significant impact. Limited prospective data contributes to uncertainty of estimate.

Background: Economic evaluations of generalized anxiety disorder (GAD) have been limited to ≤18 months. A decision model was developed; quantifying the lifetime cost-of-illness (COI) of GAD. Methods: An incidence-based Markov-model was developed using TreeAge® software, reflecting 9 health-states (HS): physician-assessed patients (3HS), maintenance therapies(4HS), discontinuation(1HS) and death(1HS). Onset probability (ages 18-80) determined model entry. Canadian Psychiatric Association (CPA) guidelines determined pharmaco-therapy, with revisions/validation by an expert panel. Response, remission based on pooled-analysis of CPA-cited evidence. Remaining clinical rates, absenteeism and hospitalization retrieved from literature. Direct (clinician, pharmacotherapy, hospitalization) and indirect costs (wage rate) retrieved from government publications. Results discounted at 5%. Results: The mean COI was 2008 Canadian $31,213(SD=$9,100)/patient; 96% attributed to absenteeism. Mean age=31years, discontinued treatment=85% by 2nd year, treatment discontinuation duration, 14(SD=9) years. CONCLUSION: GAD is a costly disease with a lifetime COI<$32k/patient; absenteeism exerts a significant impact. Limited prospective data contributes to uncertainty of estimate.