Directional associations between cannabis use and depression from late adolescence to young adulthood: the role of adverse childhood experiences

Abstract

Background and aims Although the co‐occurrence of cannabis and depression is well established, less is known about the temporal sequence of cannabis use and depression. The present study had three main aims: to test a symptom‐driven pathway in which depression may drive increases in cannabis use, to test a substance‐induced pathway in which cannabis use may drive increases in depression and to assess a shared vulnerability model assessing associations between individuals who have (and have not) experienced adverse childhood experiences (ACEs). Design Data are from an ongoing, longitudinal, cohort study (n = 2234). Data were set up in an accelerated longitudinal design from age 17 to 24 years. Setting Initial sample was recruited from Southern California, USA. The majority of participants still live in Southern California. Participants On average, participants were aged 18 years at wave 8, with more than half identifying as female (54.3%; n = 1350). Most participants identified as Hispanic (1127; 45.4%), followed by non‐Hispanic white (510; 20.5%), Asian (503; 20.2%), multi‐racial/other (284; 11.4%) and non‐Hispanic black (60; 2.2%). Measurements Primary outcomes were past‐month days of cannabis use and depression symptoms [patient health questionnaire (PHQ)‐8]. The Adverse Childhood Experiences scale was used as our main grouping measure. Findings In the full sample, we showed that prior levels of depression symptoms were associated with a decrease in cannabis use [opposite to the proposed symptom driven model; B = −0.33 (−0.58, −0.09)]. Dynamic coupling parameters noted individuals who evidenced greater increases in cannabis use between two prior ages reported greater increases in depressive symptoms between subsequent ages [support for a substance‐induced pathway; B = 0.53 (0.18, 0.89)]. Similar to the overall sample, for those who had not experienced ACEs, as cannabis use increased we saw a steady increase in depression [support for a substance induced pathway; B = 0.14 (0.04, 0.29)]. However, for those who experienced ACEs, as cannabis use increased we saw a consistent decrease in depression [opposite to the proposed substance‐induced pathway; B = −0.18 (−0.28, −0.08)]. Conclusion There is mixed support for both symptom‐driven and substance‐induced pathways between cannabis use and depression.

Marijuana use among community‐dwelling older adults: A population‐based study

“…These findings are consistent with prior studies linking marijuana use to mental health problems in older adults 15,21,43 . Although some individuals with mood disorders may be attempting to self‐medicate their symptoms with marijuana, there is evidence from longitudinal studies of younger people that marijuana use, especially frequent and/or heavy use, increases the likelihood of these symptoms 44–48 . Similarly, reductions in marijuana use may result in decreased depression scores 49,50 although this work needs to be replicated in older adults.…”

“…15,21,43 Although some individuals with mood disorders may be attempting to self-medicate their symptoms with marijuana, there is evidence from longitudinal studies of younger people that marijuana use, especially frequent and/or heavy use, increases the likelihood of these symptoms. [44][45][46][47][48] Similarly, reductions in marijuana use may result in decreased depression scores 49,50 although this work needs to be replicated in older adults. Research conducted in younger people indicates that the link between marijuana use and psychiatric symptoms may be related to reduced dopamine synthesis capacity in individuals who use marijuana.…”

Cannabis use and mood disorders: a systematic review

“…Among these studies, 22 identified a significant temporal association between baseline cannabis use and subsequent depression. Cannabis use was a significant predictor of adulthood depression across 12 sample sets following adolescents ( 20 , 34 , 42 , 59 , 60 , 66 , 70 , 74 , 78 , 82 , 84 , 89 ). In a sample of LGB and heterosexual adolescents, London-Nadeau and colleagues observed that cannabis use at age 13 predicted depression symptoms at ages 15 and 17 among LGB participants only ( 70 ).…”

“…However, a bidirectional relationship was also identified among LGB adolescents, where baseline depressive scores predicted subsequent cannabis use. In one study that tracked a cohort of Australian young adults from birth, and after controlling for covariates, individuals who used cannabis at least once a week were more likely to report depressive symptoms than those who never used cannabis or those who used cannabis less than weekly ( 42 ). Furthermore, among young adults who used cannabis at least weekly, the risk of reporting depressive symptoms was greater among those who initiated cannabis use before the age of 15.…”