When Household Members Quit Cannabis, Teens' Mental Health Improved | Research

The takeaway

Adolescents whose household members stopped using cannabis showed improvements in mental health symptoms — and reduced family conflict and better sleep appeared to explain part of the benefit.

Family therapists and counselors, parents considering how their cannabis use affects children, public health researchers studying household-level substance effects.

What the researchers found

Using longitudinal data from the ABCD Study, researchers identified adolescents (ages 10–13) living in households where someone used cannabis, then tracked what happened to the teens' mental health when household members stopped.

After propensity score matching to control for demographic and psychological differences, household cannabis cessation was associated with improvements in adolescents' internalizing problems (anxiety, depression), externalizing problems (conduct, aggression), and psychotic-like experiences.

The study went further to identify potential pathways. Two mediators emerged: family conflict decreased when household cannabis use stopped, and adolescents' sleep problems improved. Both reductions were associated with the mental health improvements — suggesting that household cannabis cessation benefits teens not just by removing direct exposure but by improving the family environment and the teen's sleep quality.

Psychotic-like experiences (PLEs) were assessed separately using the Prodromal Questionnaire, adding specificity to the mental health outcomes beyond general behavioral checklists.

Why it matters

Most cannabis mental health research focuses on the user themselves. This study asks a different question: what happens to the children in the household? The finding that household cessation improves teen mental health — mediated through reduced family conflict and better sleep — suggests that cannabis use affects families, not just individuals.

The numbers in context

ABCD Study, adolescents ages 10–13. Household cessation associated with improved internalizing, externalizing, and psychotic-like experiences. Two significant mediating pathways: reduced family conflict and improved sleep. Propensity score matching used to balance groups.

How the study worked

Longitudinal cohort study using ABCD Study waves 2 and 3. Included adolescents ages 10–13 with household cannabis use at wave 2. Cessation defined as absence of household member cannabis use at wave 3. Propensity score matching for demographic and psychometric confounders. Outcomes: Child Behavior Checklist (internalizing, externalizing), Prodromal Questionnaire-Brief (psychotic-like experiences). Mediators: Family Environment subscale (conflict), Sleep Disturbance Scale for Children.

Who was studied

N=1,426 adolescents aged 10-13 years, US cohort study with household cannabis exposure.

What this study cannot tell us

Observational design — household cessation may coincide with other positive changes (employment, relationship improvement, reduced stress) that independently benefit teen mental health. Household cannabis use was assessed by report, which may be inaccurate. Cannot determine whether effects are from secondhand exposure, household environment, genetic factors, or some combination. Two-wave comparison limits trajectory analysis.

How to read the evidence

Longitudinal cohort study with propensity score matching and mediation analysis — stronger than cross-sectional studies but still observational with potential unmeasured confounders.

When this study was published

Published in 2026 using recent ABCD Study data, providing timely evidence on household-level cannabis effects on adolescent mental health.

The bigger picture

This family-level perspective connects to the individual adolescent research. The expectancy trajectories study (RTHC-00272) found that family dynamics shaped cannabis attitudes. The discrimination-to-intention study (RTHC-00264) showed environmental factors influence cannabis risk. This study adds that household substance use — and its cessation — directly affects teen mental health through the home environment. The sleep finding links to the cannabis-sleep research (RTHC-00281, RTHC-00012): if household cannabis use disrupts teen sleep (through secondhand exposure, household disruption, or other mechanisms), cessation would improve both sleep and the mental health outcomes that depend on it.

Replication

Not stated in abstract.

Funding

Not reported in abstract.

Conflicts of interest

Not reported in abstract.

Questions still open

Is the benefit driven by reduced secondhand cannabis exposure, improved family functioning, or both? Would the same pattern hold for other household substance use (alcohol, tobacco)? Could family-based interventions that address household cannabis use be a novel pathway to improving adolescent mental health?

Read the original research

Household cannabis cessation and adolescent mental health outcomes in a prospective cohort study.

BMC medicine

BMC Medicine is a reputable open-access journal that publishes high-quality research in all areas of medicine.

View on PubMed ↗Publisher’s paper ↗

Citation

Wang, Ming; Xu, Yixiang; Huang, Runqi; Sun, Yunjun; Zhang, Lingli; Zhou, Wei; Zhang, Qingli; Luo, Qiang; Du, Wenchong; Ren, Tai; Li, Fei. (2026). Household cannabis cessation and adolescent mental health outcomes in a prospective cohort study.. BMC medicine. https://doi.org/10.1186/s12916-026-04668-4