TY - JOUR
T1 - Using Mendelian randomization analysis to better understand the relationship between mental health and substance use: A systematic review
AU - Treur, Jorien L.
AU - Munafò, Marcus R.
AU - Logtenberg, Emma
AU - Wiers, Reinout W.
AU - Verweij, Karin J. H.
N1 - Funding Information: Financial support. JLT was supported by a Veni grant from the Netherlands Organization for Scientific Research (NWO; grant number 016.Veni.195.016). KJHV and JLT were supported by the Foundation Volksbond Rotterdam. Publisher Copyright: Copyright © The Author(s), 2021. Published by Cambridge University Press. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/7
Y1 - 2021/7
N2 - Background Poor mental health has consistently been associated with substance use (smoking, alcohol drinking, cannabis use, and consumption of caffeinated drinks). To properly inform public health policy it is crucial to understand the mechanisms underlying these associations, and most importantly, whether or not they are causal. Methods In this pre-registered systematic review, we assessed the evidence for causal relationships between mental health and substance use from Mendelian randomization (MR) studies, following PRISMA. We rated the quality of included studies using a scoring system that incorporates important indices of quality, such as the quality of phenotype measurement, instrument strength, and use of sensitivity methods. Results Sixty-three studies were included for qualitative synthesis. The final quality rating was '-' for 16 studies, '- +' for 37 studies, and '+'for 10 studies. There was robust evidence that higher educational attainment decreases smoking and that there is a bi-directional, increasing relationship between smoking and (symptoms of) mental disorders. Another robust finding was that higher educational attainment increases alcohol use frequency, but decreases binge-drinking and alcohol use problems, and that mental disorders causally lead to more alcohol drinking without evidence for the reverse. Conclusions The current MR literature increases our understanding of the relationship between mental health and substance use. Bi-directional causal relationships are indicated, especially for smoking, providing further incentive to strengthen public health efforts to decrease substance use. Future MR studies should make use of large(r) samples in combination with detailed phenotypes, a wide range of sensitivity methods, and triangulate with other research methods.
AB - Background Poor mental health has consistently been associated with substance use (smoking, alcohol drinking, cannabis use, and consumption of caffeinated drinks). To properly inform public health policy it is crucial to understand the mechanisms underlying these associations, and most importantly, whether or not they are causal. Methods In this pre-registered systematic review, we assessed the evidence for causal relationships between mental health and substance use from Mendelian randomization (MR) studies, following PRISMA. We rated the quality of included studies using a scoring system that incorporates important indices of quality, such as the quality of phenotype measurement, instrument strength, and use of sensitivity methods. Results Sixty-three studies were included for qualitative synthesis. The final quality rating was '-' for 16 studies, '- +' for 37 studies, and '+'for 10 studies. There was robust evidence that higher educational attainment decreases smoking and that there is a bi-directional, increasing relationship between smoking and (symptoms of) mental disorders. Another robust finding was that higher educational attainment increases alcohol use frequency, but decreases binge-drinking and alcohol use problems, and that mental disorders causally lead to more alcohol drinking without evidence for the reverse. Conclusions The current MR literature increases our understanding of the relationship between mental health and substance use. Bi-directional causal relationships are indicated, especially for smoking, providing further incentive to strengthen public health efforts to decrease substance use. Future MR studies should make use of large(r) samples in combination with detailed phenotypes, a wide range of sensitivity methods, and triangulate with other research methods.
KW - Mendelian randomization
KW - Systematic review
KW - alcohol
KW - caffeine
KW - cannabis
KW - cognitive functioning
KW - mental disorders
KW - smoking
KW - substance use
UR - http://www.scopus.com/inward/record.url?scp=85106927693&partnerID=8YFLogxK
UR - https://pure.uva.nl/ws/files/99343661/S003329172100180Xsup001.xlsx
UR - https://pure.uva.nl/ws/files/99343663/S003329172100180Xsup002.docx
U2 - https://doi.org/10.1017/S003329172100180X
DO - https://doi.org/10.1017/S003329172100180X
M3 - Review article
C2 - 34030749
SN - 0033-2917
VL - 51
SP - 1593
EP - 1624
JO - Psychological Medicine
JF - Psychological Medicine
IS - 10
ER -