Smoking is a public health problem for which psychiatrists show increasing interest. For the development and the continuation of the smoking habit both psychosocial factors and the neuroregulating effects of nicotine are important. Nicotine is a psychoactive drug that may cause a persistent dependence which is hard to treat. Nicotinedependence is very similar to other types of dependence on psychoactive drugs, and has consequently to be considered as a psychiatric disorder. Epidemiology has shown that smoking is related to psychiatric disorders such as schizophrenia, depression and alcoholism. The nature of this relationship is not yet clear, but the effects of nicotine on different neurotransmitters probably play an important role. In psychiatric clinics, and in scientific research, smoking appears to be a relevant factor. Implementation of no-smoking policies in psychiatric hospitals should take account of the special meaning of smoking in the psychiatric subculture.