The review looked at 46 prior studies that assessed the association between maternal prenatal smoking and offspring ADHD diagnosis. The review specifically included studies accounting for genetic effects, in addition to conventional approaches.
Some of those studies had a low risk of bias (meaning they are unlikely to give misleading results) and were able to take into account genetic effects. Those studies indicate that shared genetics plays a substantial role in the association of offspring ADHD with prenatal smoking. This is supported by a previous systematic review based on genetically informed designs which also concluded that the association between maternal prenatal smoking and ADHD is explained by shared genetics.
Read the full University of Bristol press release
Paper: ‘Prenatal smoking, alcohol and caffeine exposure and offspring externalizing disorders: a systematic review and meta-analysis’ by Elis Haan et al. in Addiction.