Cost effectiveness study of a year follow-up of selective serotonin reuptake inhibitor (SSRI) and augmentor combination compared with SSRI and placebo.

We describe a method for evaluating the value of increased cost of pharmacological augmentation that, taken for 6 weeks, accelerates the action of an antidepressant. We test the hypothesis that, if onset of action is taken into account, any added direct costs of the augmenting agent are offset by longer term cost effectiveness. Data to illustrate the method were based on a double-blind randomized placebo controlled study, in which 80 patients originally took part. Patients received the selective serotonin reuptake inhibitor (SSRI) antidepressant paroxetine and an augmenting agent (pindolol) or placebo. After 6 weeks, patients were offered SSRI alone on an open label basis for up to 6 months. At that point they were discharged to their general practitioner or local psychiatric services and subsequently assessed by us at one year. We have used techniques of decision analysis, cost effectiveness and cost benefit and have included a sensitivity analysis. The direct costs over one year of SSRI and augmenting agent, if taking the acceleration effect into account, represented greater cost effectiveness than the SSRI antidepressant alone. The cost effectiveness analysis was positive in both cases. We conclude that the direct costs of treatment are higher than those of previous calculated with SSRIs; but the rate of onset must be taken into account. The application of the model appears valid and useful, and may be used as part of the evaluation of other augmentation regimes.