 Patients will be randomised to two groups of 10-18 patients each. One group will receive 7x verum treatment with tDSC, the other 7x sham treatment. All participants will then receive standardised behavioural therapy The smoke-free programme. Both patients and clinical raters will be blind to the treatment condition. Unblinding will take place only after completion of the study or if the whole study is discontinued because of severe incidents. 