Ischemic Stroke in Young Adults and Preexisting Psychiatric Disorders: A Nationwide Case-Control Study.

Ischemic strokes in adults younger than 45 years of age were regarded as a relatively uncommon event in the proportion of <5% of all ischemic strokes.1 However, other epidemiological studies have shown a higher proportion of approximately 10% of all ischemic strokes occurring in young adults.2,3 Compared with stroke in the elderly, stroke in the young adult resulted in a disproportionately great personal, familial, and socioeconomic impacts and consequences by leaving patients disabled before their most productive years.4,5 The most significantly established risk factors for young ischemic stroke included hypertension, dyslipidemia, diabetes mellitus, and smoking.5–7 The association between psychiatric disorders and stroke has gained the clinical and scientific attention in the past decade.8–10 For example, Tsai et al11 followed 80,569 patients with schizophrenia for 5 years, and revealed that those with schizophrenia were 1.13 times more likely to have a stroke (95% confidence interval [CI]: 1.05∼1.22). Li et al12 followed 1003 patients with major depression and 4012 controls for 9 years and found that patients with major depression had a higher risk of stroke (odds ratio [OR]: 1.55, 95% CI: 1.08∼2.211) than the control group during the follow-up. Dong et al8 reported a significant positive association between depression and subsequent risk of stroke (relative risk [RR]: 1.34, 95% CI: 1.17∼1.54). Prieto et al's10 meta-analysis study composed of 27,092 bipolar patients showed that the risk of stroke in bipolar disorder was significantly increased (RR: 1.74, 95% CI 1.29∼2.35). The First National Health and Nutrition Examination Survey in United States demonstrated that more anxiety symptoms at baseline were associated with increased risk of incident stroke (hazard ratio [HR]: 1.14, 95% CI: 1.03∼1.25).9 Following 19,544 men aged 40 to 59 years for 11 years, Iso et al13 determined that alcohol consumption was positively associated with the risk of stroke with a 68% excess risk among drinkers of ≥450 g ethanol per week compared with occasional drinkers. However, stroke in the above studies occurred in the late mid-life or in old age but not in the younger age groups. The association between young stroke and psychiatric disorders was less investigated and still unclear. In our study, using the Taiwan National Health Insurance Research Database (NHIRD) with a large sample size and a retrospective study design, we investigated the association between the young ischemic stroke and the risk of preexisting psychiatric disorders, including schizophrenia, bipolar disorder, major depression, anxiety disorders, and alcohol use disorder.