Table 1.

Final smoking cessation intervention concept.

Component	Core elements	Frequency/duration/ dose	Responsible mental health care professional
Behavioural Counselling	Group meetings by default, with additional individual counselling if needed. •Motivational preparation for smoking cessation •Psycho-education on: 1. Basic mechanisms of nicotine addiction 2. Physical/mental/emotional effects of smoking cessation in the context of mental health problems 3. Effects of smoking cessation medication •Normalisation of relapse •Personalised relapse prevention plan •Critical assessment of risks and subjective benefits of smoking •Challenging core beliefs and thoughts that maintain tobacco use (including cannabis use if applicable) through CBT techniques such as behavioural experiments •Improving emotion regulation, e.g., dealing with stress •Dealing with withdrawal symptoms and craving	•Month 1–3: weekly •Month 4–12: monthly	Mental health care specialist nurse psychologist
Pharmacological treatment (options)*	(1) Nicotine replacement therapy (chewing gum, patches, pastilles)	Total duration: up to 6 weeks	Mental health care specialist nurse psychiatrist/physician
	(2) Varenicline	Total duration: 12 weeks quit date between week 1 and week 2 of treatment cycle
	(3) Bupropion	Total duration: 9 weeks
Peer support	•Regular group meetings with non-therapeutic approach •Connecting participants and creating group cohesion •Creating a safe environment in which participants can share experience •Participants can gain hope from positive attitude and deep understanding of expert-by-experience Group meetings do not have fixed content. Participants decide on discussion topics or activities together.	Month 1–3: weekly Month 4–7: bi-weekly Month 8–12: monthly	Expert-by-experience

*Building up and tapering off doses are determined through shared decision making between patient and mental health care professional following national guidelines.