Effectiveness of a one-year smoking cessation intervention for people with severe mental illness: results of the KISMET cluster-randomized controlled trial

Clinical Snapshot

Key Findings

• P Value: Not reported, but CI suggests p≈0.05

• Effect Size: OR 4.2 favoring KISMET intervention

• Primary Outcome: Self-reported smoking cessation verified by exhaled CO <10ppm at 12 months

• Nnt Or Sensitivity: NNT cannot be calculated from available data due to missing absolute cessation rates

• Confidence Interval: 95% CI 1.0 to 17.2

Clinical Application

Requires trained staff for CBT and peer support delivery; high dropout rates suggest implementation challenges Relevant to Australian mental health services; intervention components align with RACGP smoking cessation guidelines; PBS subsidizes smoking cessation pharmacotherapy Adults with severe mental illness in outpatient settings who smoke and are motivated to quit

Abstract

BACKGROUND: This study evaluated the effectiveness of a one-year smoking cessation intervention for people with severe mental illness compared with treatment as usual (TAU) in outpatient mental healthcare. METHODS: The KISMET study is a pragmatic cluster-randomized controlled trial conducted in 21 outpatient mental healthcare teams in the Netherlands. Eleven teams delivered the KISMET intervention comprising cognitive-behavioral and peer support, combined with optional pharmacological reatment. Ten teams participated in the TAU condition. We collected data between October 2022 and July 2024. The primary outcome was self-reported smoking cessation at 12 months, verified through exhaled carbon monoxide levels below 10 parts per million. Secondary outcomes included depression and anxiety (HADS), severity of psychotic symptoms (PANSS-6), quality of life (SF-12), disease self-management (PAM-13), lipid profile, blood pressure, body mass index, glucose level, and physical fitness. Crude and adjusted linear and multivariable logistic regression and mixed model analyses were performed. RESULTS: Eighty-nine participants were included in the KISMET intervention and 44 in TAU. Smoking cessation rates were significantly higher in the KISMET group at 3 months (OR 12.1, 95% CI 1.4 to 103.7) and at 12 months (OR 4.2, 95% CI 1.0 to 17.2) but not at 6 months (OR 1.9, 95% CI 0.5 to 6.9). No significant differences between groups were found for secondary outcomes. Dropout rates were 58% in the intervention and 32% in the TAU group. CONCLUSIONS: The KISMET intervention shows potential without signs of physical or psychopathological complications. However, results must be interpreted with the high dropout rates in mind.

References

1. 1.Küçükaksu, M., Hoekstra, T., Vermeulen, J. M., Jansen, L., Helmig, S., van Meijel, B., & Adriaanse, M. C. (2026). Effectiveness of a one-year smoking cessation intervention for people with severe mental illness: results of the KISMET cluster-randomized controlled trial. Psychological Medicine. https://doi.org/10.1017/S0033291726104516