A prospective study in one year cumulative incidence of depression after ischemic stroke and Parkinson's disease: A preliminary study

Background and aims: 1) To measure the one year cumulative incidence of depression after ischemic stroke event and 2) to compare its incidence with that of Parkinson's disease (PD) in an outpatient neurology department. Materials and methods: Stroke patients were recruited after their first diagnosis and PD patients were recruited during the same recruitment period. Main measures included: 1) disability (Barthel Index and Modified Rankin Scale), 2) cognitive function (Thai Mental State Examination and 3) depression (Clinical Interview Schedule-Revised). The patients were assessed at 1, 2, 3, 6 and 12 months. Results: Seventy-seven stroke patients with hemispheric infarction and 59 PD patients were recruited. The baseline characteristics of the two groups were comparable except that stroke patients were 4 years younger. The cumulative one year incidence of depression was 12% after stroke and 5.1% in PD with no significant difference. Cox regression analysis showed that the risk for depression among stroke cohort was almost three times higher, although not statistically significant, than that among PD cohort (hazard ratio 2.92). In stroke, depression mainly occurred within 3 months after the event but in PD, depression developed randomly throughout the follow up period. Conclusion: The one year cumulative incidence of post-stroke depression in the Thai population is much lower than in the Caucasian population. However, its adjusted cumulative incidence was much higher to that of PD. The findings are in line with previous studies that stroke significantly contributes to the pathogenesis of depression.