Gemma Lewis

Dr Lewis is a psychiatric epidemiologist whose research focuses on the causes, prevention and treatment of common mental health problems including depression and anxiety. Her research also includes self-harm and suicidality, which are strongly associated with depression and anxiety. She uses large population-based datasets and advanced methods of causal inference to inform prevention. She analyses data from large pragmatic clinical trials, to inform treatment. As depression and anxiety often begin during adolescence, much of her research focuses on young people.


Investigating the association between alcohol consumption and dependence during adolescence, and risk of depression in young adulthood


Background: The association between alcohol dependence and risk of subsequent depression in young people is poorly understood. We examined change in alcohol dependence from ages 16 to 23, accounting for the role of consumption. We examined associations between initial levels and change in alcohol dependence and consumption, with subsequent depression.

Methods: Prospective cohort study using ALSPAC data. Alcohol consumption and dependence were measured at ages 16, 18, 19, 21 and 23. Depression was assessed at age 24. Analyses were latent growth curve models, before and after adjusting for confounders.

Results: There was no evidence for an association between alcohol consumption and depression. There was strong evidence for a positive association between the intercept for alcohol dependence (at age 18) and depression at age 24 [probit coefficient (95% CI): 0.18 (0.11, 0.26); p < 0.001; standardised probit: 0.18]. This is equivalent to a 12% probability of depression for those with average levels of alcohol dependence at age 18, and an average linear slope. There was no evidence for an association between the linear slope for alcohol dependence and depression.

Conclusions: Alcohol dependence but not consumption increases the risk of depression among young people. Population-based interventions for alcohol dependence could prevent depression.

Funding: MRC Grant on alcohol and health awarded to Prof Matt Hickman as PI (ref: MR/L022206/1)