LAUSR

BACKGROUND We seek to clarify the causal nature of the bidirectional associations, in adulthood, between Substance Use Disorder (SUD) and Psychosocial Dysfunction (PSD). METHODS As assessed from National Swedish registers, SUD is measured by Alcohol Use Disorder (AUD) and Drug Use Disorder (DUD) and Psychosocial Dysfunction (PSD) by unemployment (UN), low income (LI) and high community deprivation (HCD). A cross-lagged structural equation model from ages 31 to 48 is applied to the native Swedish population born 1960-1980 and residing in Sweden at age 29 followed through 2017 (n=2,283,330), excluding individuals with prior SUD and PSD. RESULTS All models fitted well. Focusing on the cross-lagged paths, across sexes¸ substances and forms of PSD, parameter estimates for the SUD→PSD paths consistently exceeded those for the parallel PSD→SUD paths. SUD→PSD paths were nearly all statistically significant. While the UN→SUD and LI→SUD paths were usually significant, most HCD→SUD paths were not. The differences between the UN→SUD and SUD→UN paths grew larger with increasing age, while the opposite pattern was seen for the HCD→SUD and SUD→HCD paths. CONCLUSIONS Across sexes, forms of SUD and dimensions of PSD, in a fully parametrized and good-fitting cross-lagged model of middle adult life, a diagnosis of SUD consistently predicted future PSD while PSD often but not always predicted future SUD. The SUD→PSD paths were consistently larger than the parallel PSD→SUD paths. Our results suggest a bidirectional causal relationship between SUD and PSD across adulthood, driven largely, but not entirely, by the negative effects of SUD on future psychosocial functioning.