Relationship between smoking and family history of smoking in schizophrenia patients

The rate of smoking is known to be high in patients with schizophrenia. The purpose of this study was to quantitatively examine the relationship between smoking and family history of smoking in patients with schizophrenia.

The sample consisted of 172 patients (mean age: 54 years, 55% male) hospitalized in a general psychiatric hospital. They were asked by a physician whether they smoked. Family histories of smoking and schizophrenia were assessed among first- and third-degree relatives.

Ninety-eight patients (57%) were identified as having smoked at some point. Multiple logistic regression analysis showed that smoking was significantly associated with family histories of smoking among both first- and third-degree relatives, controlling for the effects of age, sex, and family history of schizophrenia. The smoking rates were significantly higher in those with a family history of smoking, but not a family history of schizophrenia, than among those without a family history of either smoking or schizophrenia. However, this difference did not reach statistical significance among those with a family history of schizophrenia.

Smoking is greatly influenced by family history of smoking in patients with schizophrenia, especially among those without a family history of schizophrenia. The association between smoking and family history of smoking was inconclusive among those patients with schizophrenia who also had a family history of schizophrenia.