Objective: Previous studies of smoking habits of schizophrenic patients have found rates as high as 88%. The authors report the smoking habits of all known schizophrenic patients within a discrete geographical area and compare them with the smoking habits of a general population sample.
Method: All known schizophrenic patients in Nithsdale in South-West Scotland (N = 168) were invited to complete a questionnaire on smoking habits. Also assessed were mental state, drug-related side effects, and premorbid childhood personality and social adjustment.
Results: One hundred thirty-five of the 168 patients returned the questionnaires. The rate of smoking among the patients was 58% (N = 78), compared with 28% in the general population. Sixty-eight percent of the patients who smoked (N = 53) had 25 or more cigarettes per day. The mean age at starting smoking was 17 years in both patients and normal subjects. Ninety percent of the patients who smoked (N = 70) started smoking before the onset of schizophrenia. Patients who smoked were younger than nonsmokers, and more of them were male. They had had more hospitalizations, and more were in contact with psychiatric services. More were receiving intramuscular antipsychotic medication. Smokers had poorer childhood social adjustment. Among the female patients, there was a positive correlation between age at starting smoking and age at onset of schizophrenia.
Conclusions: The rate of smoking and level of nicotine addiction are greater in schizophrenic patients than in the general population. Smoking may be a marker for the neurodevelopmental form of the illness and may be another environmental risk factor for schizophrenia in vulnerable individuals.