How do psychological characteristics of family members affected by substance use influence quality of life?

PURPOSE: Addiction is a major health stressor for families, representing an under-researched area with important policy implications. The current aim was to validate the Composite Codependency Scale, which captures the psychological characteristics of affected family members, and assess quality of life as mediated by family functioning. METHODS: Close relatives (n = 271) of patients in treatment for substance use disorder (SUD) participated in a 4-day psychoeducational program. We also recruited a general population sample (n = 393) via an online social media site. Data were analyzed using multigroup confirmatory factor analysis (MGCFA) and a latent regression model. Differences in subscale latent means were applied to ascertain how the scale discriminated the two populations. RESULTS: MGCFA yielded a shortened, nine-item partial scalar invariant scale (SCCS) that allowed comparison of latent means. The SCCS discriminated between family members and the general population, with family scoring higher on all three scale dimensions. By effect size, family had higher means (mean differences; 95% confidence intervals) for ‘emotional suppression’ (0.48; 0.36–0.59; p < 0.001; effect size, 0.92), ‘interpersonal control’ (0.47; 0.36–0.59; p < 0.001; effect size, 0.97), and ‘self-sacrifice’ (0.20; 0.10–0.29; p < 0.001; effect size, 0.43). Higher SCCS scores were associated with greater family dysfunction (β = 1.00, 95% CI 0.63–1.36; p < 0.001) and worse quality of life (β = − 0.23, 95% CI − 0.30 to − 0.16; p < 0.001), confirming the concurrent validity of the SCCS. CONCLUSION: When family members of people with addictions had the psychological characteristics of suppressing their emotions, believing they could fix others’ problems, and neglecting their own for others’ needs, they also had more family dysfunction and poorer quality of life. The SCCS offers a valid instrument for addressing the life situation of affected families. This scale can help clinicians focus on family members within health services, especially within SUD treatment services. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11136-019-02169-x) contains supplementary material, which is available to authorized users.