Validity of self-reported smoking in schizophrenia patients
Version of Record online: 18 MAY 2010
© 2010 The Authors. Journal compilation © 2010 Japanese Society of Psychiatry and Neurology
Psychiatry and Clinical Neurosciences
Volume 64, Issue 3, pages 274–278, June 2010
How to Cite
Takeuchi, T., Nakao, M., Shinozaki, Y. and Yano, E. (2010), Validity of self-reported smoking in schizophrenia patients. Psychiatry and Clinical Neurosciences, 64: 274–278. doi: 10.1111/j.1440-1819.2010.02082.x
- Issue online: 18 MAY 2010
- Version of Record online: 18 MAY 2010
- Received 5 June 2009; revised 19 January 2010; accepted 6 February 2010.
Aims: It is important to evaluate smoking status among schizophrenia patients because such patients are highly inclined to take up smoking, but only a few studies have focused on the validity of self-reported smoking in relation to schizophrenia. The aim of the present study was therefore to determine the validity of self-reported smoking and to investigate whether self-reported smoking is biased in schizophrenia patients.
Methods: A total of 158 schizophrenia patients answered self-rated questions of smoking status, and the level of carbon monoxide (CO) in expired air was measured. The relationship of the self-reported smoking to the CO levels was determined, and interaction of the disease duration and education level on this relationship was evaluated using correlation and receiver operating characteristic analyses.
Results: The CO levels in the expired air were found to be positively related to the self-reported data (P < 0.01). The stratified data on the duration of schizophrenia indicated that the positive relationship between self-reported smoking and the CO concentration became less obvious with the increase in duration of schizophrenia (Ptrend < 0.01). In contrast, the stratified data on education level did not indicate any such significant modifying effect.
Conclusions: Although self-reporting is useful for evaluating smoking status, psychiatrists should use objective methods of measurement to assess the smoking status of chronic schizophrenia patients.