A longer diagnostic interval is a risk for depression in amyotrophic lateral sclerosis

Objective: Recognizing depressive symptoms in patients with amyotrophic lateral sclerosis (ALS) remains problematic given the potential overlap with the normal psychological responses to a terminal illness. Understanding mental health and disease-related risk factors for depression is key to identifying psychological morbidity. The present study aimed to determine the prevalence of depressive symptoms in ALS and to explore mental health and disease-related risk factors for depression.  Method: Structured medical and psychiatric history questionnaires and a validated depression scale (Depression, Anxiety, Stress Scale–21) were completed by 27 ALS patients (60% female; 59% limb onset; age 65.11 ± SE 2.21) prior to their initial review at a multidisciplinary clinic. Physical function was assessed with the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS–R).  Results: At the time of initial assessment, 44% of patients had a previous psychiatric history, although the majority (62%) reported no symptoms of depression. The mean ALSFRS–R score was 37.78 ± SE 1.22, with an average diagnostic interval of 16.04 ± SE 2.39 months. Logistic regression analysis revealed that the length of the diagnostic interval alone predicted depressive symptoms (χ2(3, n = 26) = 9.21, Odds Ratio (OR) = 1.12, p < 0.05.  Significance of Results: The illness experiences of ALS patients rather than established mental health risk factors influence the manifestation of depressive symptoms in the early stages of the disease, with clinical implications for the assessment and treatment of psychological morbidity. Patients with lengthy diagnostic intervals may be prime targets for psychological assessment and intervention, especially in the absence of ALS-specific tests and biomarkers.