Depression and risk of cognitive dysfunctions in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is not only a motor disorder: More than 50% of patients have cognitive dysfunctions over the course of the disease. At the same time, mood disorders may also occur in ALS patients following diagnosis due to the fatal prognosis; however, little data are available on any depression beforehand. Starting from these considerations, the aim of our study was to investigate the occurrence of depression in Italian ALS patients prior to diagnosis, evaluating its prevalence in the subjects who have developed cognitive dysfunctions and in those who did not.

We included 318 patients, establishing the presence of depression in the 5 years before ALS diagnosis. Patients underwent a complete battery of neuropsychological tests with the aim to evaluate the executive functions, behavior, language, and memory.

Before diagnosis, 40 patients with ALS had been diagnosed with depression: Among them, 29 patients had cognitive impairment over the course of the disease and only 11 did not develop any cognitive alteration (OR 1.46; 95% CI: 1.26-1.66, adjusted for sex, age, and disease phenotype, P: 0.038). Moreover, there is a significant difference in survival time between ALS patients with depression before ALS, compared to ALS patients without previous depression (P: 0.006).

We reported a high prevalence of depression in the past in patients with ALS and cognitive impairment, as compared to patients without cognitive deficits, showing also that patients with both had a shorter survival time. These aspects require multidisciplinary approach at disease onset.