Impact of health literacy on depressive symptoms and mental health-related: Quality of life among adults with addiction

Background: Health literacy has been linked to health status in a variety of chronic diseases. However, evidence for a relationship between health literacy and mental health outcomes is sparse. Objective: We hypothesized that low literacy would be associated with higher addiction severity, higher levels of depressive symptoms, and worse mental health functioning compared with those with higher literacy in adults with alcohol and drug dependence. Methods: The association of literacy with multiple mental health outcomes was assessed using multivariable analyses. Measurement instruments included the Rapid Estimate of Adult Literacy in Medicine (REALM), the Center for Epidemiologic Studies-Depression (CES-D) scale, the Mental Component Summary scale of the Short Form Health Survey, and the Addiction Severity Index for drug and alcohol addiction. Subjects included 380 adults recruited during detoxification treatment and followed prospectively at 6-month intervals for 2 years. Based on the REALM, subjects were classified as having either low (<= 8th grade) or higher (>= 9th grade) literacy levels. Results: In longitudinal analyses, low literacy was associated with more depressive symptoms. The adjusted mean difference in CES-D scores between low and high literacy levels was 4 (P <.01). Literacy was not significantly associated with mental health-related quality of life or addiction severity. Conclusions: In people with alcohol and drug dependence, low literacy is associated with worse depressive symptoms. The mechanisms underlying the relationship between literacy and mental health outcomes should be explored to inform future intervention efforts.