Latent Depressive Factor in Adolescence Predicts Marijuana Use Diagnosis in Early Adulthood: A Longitudinal Study

• In Event: Poster Session 14
  In Poster Session: PS 14 Topic - Developmental Psychopathology

Abstract

It is well-established that depression co-occurs with increased rates of marijuana use early in development. Furthermore, the growing rates of depression among adolescents and the harmful effects of marijuana use on the developing brain is a major concern for researchers. The temporal relationship between marijuana use and the onset of depression symptoms has long been unclear and understudied, particularly across development. Some researchers conclude that early marijuana use leads to more severe depressive symptoms later in development, while other researchers conclude that early onset depression leads to greater marijuana use as a form of relief for associated depressive symptoms. However, due to the cross-sectional nature of many of these studies, a clear directional relationship remains speculative.
The present study utilized a Random Intercepts-Cross Lagged Panel Model (RI-CLPM; Hamaker, Kuiper, & Grasman, 2015) which allowed us to examine time-invariant, latent factors of depression and marijuana use in comparison to time-specific factors in a longitudinal sample of adolescents. Our sample included 998 adolescents and their families recruited at the start of 6th grade (approximately aged 11) from three public middle schools in the urban area. We examined developmental transactions between depressive symptoms and self-reported marijuana use from ages 16 through 22, as well as depression and marijuana use diagnoses at age 28 (via diagnostic interview). We hypothesized that time specific marijuana use in late adolescence would predict increased depressive symptoms in adulthood, as well a diagnosis of depression. Further, it was predicted that a heightened latent factor of marijuana use across the time points would predict major depressive diagnosis in adulthood.
Results indicated that the latent factor of depression predicated a diagnosis of substance abuse, but not major depressive disorder, at age 28. Similarly, the latent factor of marijuana use predicated a diagnosis of substance abuse, but not major depressive disorder, at age 28. Time specific factors of depression predicted depression diagnoses but did not predict later substance abuse diagnosis. Similarly, time specific marijuana use predicted substance use diagnoses but not major depressive disorder diagnoses.
These findings suggest that stable individual differences in both depression and marijuana use across adolescence and emerging adulthood predict marijuana-use disorders in adulthood, while time-specific depression and marijuana use were relatively specific in predicting within-domain diagnostic outcomes, with depressive symptoms predicting later depression diagnoses, and marijuana use in early adulthood predicting later substance use diagnoses. Findings help to clarify bidirectional transactions between depression and marijuana use across a critical developmental span, and may have implications for future prevention efforts.

Authors

• Ethan Isaac Kinstler, Case Western Reserve University
  Presenting Author

• Sam B Seidman, Case Western Reserve University
  Non-Presenting Author

• Arin M Connell, Case Western Reserve University
  Non-Presenting Author