Affective disorders in motor neuron disease: a population-based study.

Several studies have suggested that there may be an increased prevalence of affective disorders in people with motor neuron disease (MND). However, the literature is inconsistent, possibly because of small sample sizes in the existing studies. The Canadian province of Alberta has a universal health care system in which physician contacts are recorded along with ICD-9-CM diagnostic codes. In this analysis, diagnostic codes indicative of MND and affective disorders were used. Stratified analysis and logistic regression were used in the analysis. There were 336 cases of MND leading to a prevalence of 14.5 per 100,000 in provincial residents > or =20 years old. Affective disorders were identified in 8.6% of the total population during the same year. The crude odds ratio for affective disorders in MND was 2.3 (95% CI = 1.7-3.0). However, the prevalence of affective disorders declined with increasing illness duration.