Elevated suicide risk among patients with multiple sclerosis in Sweden

Results from previous studies of suicide risk among patients with multiple sclerosis (MS) are inconsistent. This may be explained partly by differences in methodology and study populations. The purpose of our study was to investigate suicide risk among hospital patients with MS in Sweden. During the period 1969-1996, 12,834 cases were recorded in the Swedish Hospital Inpatient Register, with 77,377 hospital admissions, in which MS was a primary or secondary diagnosis at discharge. The mean follow-up time for the whole cohort was 9.9 (SD 7.3) years. When the data for these MS patients were linked to the Swedish Causes of Death Register for the same period, 5,052 (39.4%) were found to have died. Among the 5,052 deaths, suicide was an underlying cause of death in 90 cases (1.8%). The mean period between the initial admission date with an MS diagnosis at discharge and the date of death for the 90 MS suicide cases was 5.8 (SD 5.1) years. This was significantly shorter (p = 0.002) than the mean of 7.9 (SD 6.4) years for MS cases who died due to other causes. Suicide risk, calculated as the standardized mortality ratio (SMR), was significantly elevated (SMR = 2.3) among both male and female MS cases compared with the general population. Suicide risk was particularly high in the first year after initial admission with an MS diagnosis, and among younger male MS cases. The mean age at the time of suicide was 44.5 (SD 12.4) years, and 58% of the suicides were committed within 5 years after the first admission with an MS diagnosis. The crude suicide rate among MS patients during the study period was 71 per 100,000 person-years. The rate was significantly higher (p < 0.001) in males (114) than in females (47), with an odds ratio of 2.4 (95% CI: 1.6-3.8). These findings have implications for suicide preventive measures in neurological practice.