Necessary number of participants not achieved and high drop out rate

To investigate the effectiveness of a smoking cessation intervention of two sessions (120 min at a time) in a group setting on the basis of Motivational Interviewing (MI) and important elements of Cognitive Behavioural Therapy (CBT). According to national and international guidelines patients are advised to quit and pharmacologically supported with one of the established first line smoking cessation treatments.

The study design is multicentric, prospective, randomized and controlled. The study is taking place in cooperation with smoking clinics of 5 centres in Germany (Heidelberg, Stuttgart, Munich, Chemnitz, Berlin). A total number of 800 smokers is calculated to participate in the study. After enrollment participants are randomized in one of the three intervention groups: (A) "Advice only", (B) "Brief intervention", (C) "Intensive therapy". The follow up includes a telephone interview 3 months after the last intervention, and two visits at the smoking clinics after 6 and 12 months with biochemical validation of the smoking status by measurement of the exhaled carbon monoxide and the concentration of cotinine in an urine sample respectively. The primary endpoint is the continuous abstinence rate after 12 months. Several secondary endpoints are determined amongst others the continuous abstinence rate after 6 months, point prevalence cessation rates after 6 and 12 months, life quality, weight gain, predictors of a successful cessation attempt.

Inclusion Criteria:

• Smoker
• Age > 18 years
• Motivation to quit smoking

Exclusion Criteria:

• severe somatic comorbidity or reduced life expectancy
• severe episode of a psychiatric disease
• reduced cognitive ability
• abuse of alcohol or illicit drugs
• other reasons at the discretion of responsible local study tutor