Spanish adaptation and validation of the ALS Depression Inventory-12 (ADI-12) in patients with Amyotrophic Lateral Sclerosis

Abstract

Background. Patients with Amyotrophic Lateral Sclerosis (ALS) have a higher preva- lence of mood disorders, including depression, than the general population. Non-specific measurement instruments have been used to evaluate depression in these patients, which complicates accurate diagnosis. The ALS Depression Inventory (ADI-12) exclusively as- sesses depressive symptoms in patients with ALS. Aim. To adapt and validate the ADI-12 in a Spanish sample. Methods. A selective design was used with 74 patients with ALS, using the ADI-12 questionnaire. The original instrument was translated and back-translated into Spanish. The internal structure, temporal stability, convergent, and discriminant validity of the instrument were analyzed. Results. Two confirmatory models showed internal validity (p = 0.502 for the one-factor model, p = 0.507 for the two-factor model). The Cronbach’s alpha (0.900 in the first measurement and 0.889 in the second one) indicated a high internal consistency of the test. The Pearson correlation (0.90) indicated high temporal stability. In terms of convergent validity, the ADI-12 showed moderate correlations with the Beck Anxiety Inventory (BAI) (0.51–0.58), and low correlations with time since ALS diagnosis (–0.26 to –0.27). Limitations. The main limitation of the present study was the small sample size. Conclusions. The ADI-12 is fitted to a single general factor of depression, and the scale shows high internal consistency and high temporal stability, therefore, its use is recommended for the diagnosis of depression in patients with ALS.