To examine the relative risk of depression among patients with amyotrophic lateral sclerosis (ALS), both in terms of depression diagnosis and use of antidepressant drugs, before and after diagnosis.
We conducted a nested case-control study including 1,752 patients with ALS diagnosed from July 2005 to December 2010 and 8,760 controls based on the Swedish national health and population registers, to assess the associations of depression diagnosis and use of antidepressant drugs with a subsequent risk of ALS. We further followed the patients with ALS after diagnosis to estimate the association of an ALS diagnosis with the subsequent risk of depression and use of antidepressant drugs.
Before diagnosis, patients with ALS were at higher risk of receiving a clinical diagnosis of depression compared to controls (odds ratio [OR] 1.7, 95% confidence interval [CI] 1.3-2.3), and the highest risk increase was noted during the year before diagnosis (OR 3.5, 95% CI 2.1-5.6). Patients with ALS also had a highly increased risk of depression within the first year after diagnosis (hazard ratio 7.9, 95% CI 4.4-14.3). Antidepressant use was more common in patients with ALS than in controls, especially during the year before (OR 5.8, 95% CI 4.5-7.5) and the year after (hazard ratio 16.1, 95% CI 11.5-22.6) diagnosis.
Patients with ALS are at higher risk of depression diagnosis and use of antidepressant drugs both immediately before and after diagnosis.