Sympathovagal Balance in Smoking Cessation

This study has the following primary aim: \- the main objective of this study is to investigate the effects of smoking cessation during quit attempts on sympathovagal balance. These effects will be observed in smokers quitting smoking with pharmacological support or without. Secondary aims of this study are also: * the definition of MSNA in smokers and non-smokers * the investigation of other parameters concerning the autonomic nervous system, like baroreflex-sensitivity, heart rate-variability before and during the quit attempt. * the definition of withdrawal symptoms and craving before, during and after the quit attempt. * the investigation of effects of smoking cues on craving and sympathovagal balance * the investigation of relapse rates after smoking cessation in correlation with the parameters mentioned above.