Pratt 2022.

Study characteristics
Methods	Design: RCT Recruitment: Clinician referrals, posters/brochures and mailings. After eligibility confirmation, potential participants were invited for an informational meeting, and interested individuals returned to review the consent form and provide written informed consent. Setting: Two urban mental health agencies (Kentucky and Massachusetts) serving primarily Medicaid beneficiaries with SMI. USA Study start date: March 1 2017. Study end date: January 31 2021
Participants	Total: N = 240 EC = 120 Assessment only = 120 Inclusion criteria: 1) Diagnosis of schizophrenia,schizoaffective disorder, or bipolar disorder, 2) enrolled in services at the research site for a minimum of 3 months, 3) regular smoker (approx. 10 cigarettes for the past 5 years) with a history of at least 1 quit attempt, 4) 18+ years Exclusion criteria: 1) Regular use of EC in the past month, 2) current interest/plan to quit smoking, 3) regular use of NRT or bupropion or varenicline to quit smoking, 4) use of emergency room or hospitalization for psychiatric reasons in the past 30 days, 5) pregnancy, 6) psychiatric instability (hospitalization in the past mth), 7) active substance use disorder Female 47.9%. Mean age 45.9 (SD 11.9). Mean CPD 18.7. Mean FTND 6.9 (SD 1.5). E‐cigarette use at baseline: No Motivated to quit: No
Interventions	EC: Cartridge Arm 1: EC  The Study Coordinator provided participants with a 2‐week supply of e‐cigarettes (EC) and instructions on their safe use. Per product packaging, each disposable EC provided up to 300 puffs, roughly the equivalent of 20 cigarettes. Participants were given the opportunity to practice using EC before leaving the appointment to ensure proper use. The Study Coordinator also provided brief information on safety (e.g. keeping EC out of the reach of children) and they gave participants additional 2‐week supplies at 2, 4, and 6 weeks. The EC arm was provided with 8 weeks of free ECs based on self‐report of regular tobacco use. Participants assigned in this arm were asked to switch combustible tobacco with ECs. The appeal of EC and health impacts were measured, but the authors were not targeting quitting combustible tobacco or reducing craving. Arm 2: Assessment only (no intervention) EC was given at final FU visit. Following randomization, Study Coordinators provided participants with appointments for follow‐up study visits, asked them to refrain from using ECs, and reminded participants that they would receive a 4‐week supply of ECs at the final follow‐up visit.
Outcomes	Baseline, 2, 4, 6, 8, 13 and 26 weeks Breath CO was measured by the blinded Research Interviewers at each visit using the Smokerlyzer Breath Carbon Monoxide Monitor (Bedfont Scientific) as a biologic measure of toxin exposure. CO, CPD, nicotine dependence, EC use (EC count) In NCT record but not reported in paper: change in cancer related toxin, 4‐(Methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol or NNAL [time frame: baseline, 4 weeks, 8 weeks, 13 weeks, 26 weeks], urine NNAL analysis AEs: Cough, itchy throat, bad throat
Study funding	The study was funded by the National Institute on Drug Abuse (NIDA, 1R01DA041416) in the United States.
Author declarations	None declared
Notes	New to 2022 update
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “Unblinded Study Coordinator randomly assigned participants within site using an automated program that stratified by diagnosis (schizophrenia vs. bipolar disorder) and amount of daily smoking (> 20 vs. ≤ 20 cigarettes), in blocks of four to assure balance between arms (1:1 ratio).”
Allocation concealment (selection bias)	Low risk	As above, automated programme
Blinding of participants and personnel (performance bias) All outcomes	High risk	Interventions of different intensity.  EC vs assessment only (control)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Blinded Research Interviewers”
Incomplete outcome data (attrition bias) All outcomes	Low risk	240 randomized participants. Among those participants, 210 (87.5%) were assessed at 8 weeks, and 214 (89.2%) were assessed at 26 weeks.
Selective reporting (reporting bias)	Unclear risk	Some outcomes not reported here