A meta-analysis of worldwide studies demonstrates an association between schizophrenia and tobacco smoking behaviors

https://doi.org/10.1016/j.schres.2005.02.010Get rights and content

Abstract

A meta-analysis of worldwide studies, found by a 10-year literature follow-up and/or by searching PubMed, was performed. Forty-two studies across 20 nations consistently demonstrated an association between schizophrenia and current smoking (weighted average odds ratio, OR = 5.9; 95% confidence interval, CI 4.9–5.7). In 32 male studies across 18 nations, the weighted average OR was 7.2 (CI, 6.1–8.3). In 25 female studies across 15 nations, the weighted average OR was 3.3 (CI, 3.0–3.6). The association between schizophrenia and current smoking remained after using severe mentally ill controls (18 studies across 9 countries, weighted average OR was 1.9, CI 1.7–2.1) and controlling for other variables (3 studies, adjusted ORs ranged 2–3).

Heavy smoking (6 studies across 4 countries, ORs ranged 1.9–6.4) and high nicotine dependence were more frequent in smokers with schizophrenia versus the general population. There was no consistent evidence that heavy smoking or high nicotine dependence was more frequent in smokers with schizophrenia versus severe mentally ill controls. Cessation rates were lower in schizophrenia smokers versus the general population.

Schizophrenia patients had a higher prevalence of ever smoking than the general population (9 studies across 6 countries, weighted average OR = 3.1, CI 2.4–3.8) and than severe mentally ill patients (5 studies across 5 countries, OR = 2.0, CI 1.6–2.4). Moreover, in two studies adjusting for confounders schizophrenia patients had an increased risk of starting daily smoking than controls. Thus, people who are going to develop schizophrenia have risk factors that make them more vulnerable to start smoking.

Introduction

Clinicians have observed for a long-time that schizophrenia patients are markedly prone to smoke tobacco (Lohr and Flynn, 1992). Although other severe psychiatric illnesses such as mood disorders are associated with tobacco smoking, the association between schizophrenia and tobacco smoking may be stronger (Hughes et al., 1986, de Leon et al., 1995, de Leon et al., 2002a, de Leon et al., 2003b, Diwan et al., 1998, LLerena et al., 2003). It has been suggested that biological factors may underlie the association between schizophrenia and tobacco smoking (Dalack et al., 1998, Freedman et al., 1997). This article explores the hypothesis that the association between schizophrenia and tobacco smoking is relatively independent of sociocultural factors and can be demonstrated across countries and cultures.

Section snippets

Methodological issues

A meta-analysis of studies conducted in different countries was performed to examine the above hypothesis. The rationale behind this review is that if an association between schizophrenia and tobacco smoking is observed in a variety of different cultures, then it is likely that a biological factor may underlie such association. Comparisons of schizophrenia patients with the general population and with other severe mentally ill patients were carried out. Schizoaffective patients were included in

Comparing current smoking in schizophrenia versus the general population

Table 1 describes 42 samples from 20 different nations and investigated a total of 7593 schizophrenia patients (62% were current smokers). Current smoking prevalences for schizophrenia patients were significantly higher than those for people from the general population, regardless of country, except in two studies: one from Japan, where current smoking prevalences in the general population are relatively high (particularly in males) and another from Colombia, where they are relatively low. The

Comparing heavy smoking among smokers with schizophrenia versus smokers from the general population

Table 6 describes 6 studies from 4 different countries. Although there was not a consistent definition of heavy smoking across these studies, the ORs were always significantly greater than 1, ranging between 1.9 and 6.4. This suggests that the odds that smokers with schizophrenia be heavy smokers are significantly greater than those of smokers from the general population. According to 3 studies, this conclusion may still be valid within males (Table 6) and according to 2 of 3 studies, this

High nicotine dependence among smokers

The FTND may reflect nicotine dependence and its brain disturbances better than heavy smoking. Unfortunately, very few studies of the association between schizophrenia and tobacco smoking have used the FTND (or its briefer version HSI). Etter et al. (2004) found that Swiss schizophrenia smokers had higher HSI scores than smokers from the Swiss general population.

Similarly a Spanish study (Gurpegui et al., 2005) found that 173 schizophrenia smokers had higher scores than 100 control smokers

Comparing smoking cessation rates among smokers with schizophrenia versus smokers from the general population

Six studies from 5 countries suggested that smoking cessation rates for schizophrenia patients were significantly smaller than the general population (Table 8). Combining these 6 studies, the cessation rate for schizophrenia patients was 9% versus cessation rates between 14% and 49% for the general population. The sample-size-weighted average of the ORs comparing cessation rates in schizophrenia smokers versus smokers from the general population was 0.19 (CI, 0.14–0.24).

Four studies suggested

Comparing ever smoking in schizophrenia versus the general population

In 8 out of the 9 studies described in Table 10, the OR comparing ever smoking in schizophrenia patients versus the general population was significantly greater than 1. The sample-size-weighted average of the 9 ORs was 3.1 (CI, 2.4–3.8). Only one study (Gurpegui et al., 2005) provided an adjusted OR after controlling for confounding variables, 1.4 (CI, 0.91–2.2) that did not reach significance.

Conclusions

A large number of worldwide studies describing current smoking in schizophrenia consistently suggest that schizophrenia patients from all countries share a biological factor that makes them more prone to smoke. Most studies examining ever smoking and two studies exploring age of smoking initiation (de Leon et al., 2002b, Gurpegui et al., 2005) suggest that there may be genetic factors increasing the risk of both becoming a smoker and developing schizophrenia. This model is supported by recent

Acknowledgements

Preliminary early versions of this article were presented by Dr. de Leon as lectures at John Umstead Hospital, Butner, NC on 8/29/02 and Burghölzli Hospital in Zurich, Switzerland on 7/12/03. Dr. Diaz was partially supported by the Dirección de Investigaciones of the Universidad Nacional, Medellin, Colombia (grants 030802738 and Apoyo a Grupos Reconocidos Colciencias 2004). Margaret T. Susce, R.N., M.L.T., and Maria Johnson, R.N., helped with editing of this article. Raimo K.R. Salokangas, MD,

References (111)

  • A. LLerena et al.

    Schizophrenia and tobacco smoking in a Spanish psychiatric hospital

    Schizophr. Res.

    (2003)
  • J.B. Lohr et al.

    Smoking and schizophrenia

    Schizophr. Res.

    (1992)
  • D.J. Luchins et al.

    Repetitive behaviors in chronically institutionalized schizophrenic patients

    Schizophr. Res.

    (1992)
  • H.C. Margolese et al.

    Drug and alcohol use among patients with schizophrenia and related psychoses: levels and consequences

    Schizophr. Res.

    (2004)
  • T. Mori et al.

    Smoking habits in Japanese patients with schizophrenia

    Psychiatry Res.

    (2003)
  • T.J. O'Farrell et al.

    Addictive behaviors among hospitalized psychiatric patients

    Addict. Behav.

    (1983)
  • A. Olincy et al.

    Increased levels of nicotine metabolite cotinine in schizophrenic smokers compared to other smokers

    Biol. Psychiatry

    (1997)
  • T.J. Payne et al.

    Assessing nicotine dependence: a comparison of the Fagerström Tolerance Questionnaire (FTQ) with the Fagerström Test for Nicotine Dependence (FTND) in a clinical sample

    Addict. Behav.

    (1994)
  • C.S. Pomerleau et al.

    Reliability of the Fagerström Tolerance Questionnaire and the Fagerström Test for Nicotine Dependence

    Addict. Behav.

    (1994)
  • M.-F. Poirier et al.

    Prevalence of smoking in psychiatric patients

    Prog. Neuro-psychopharmacol. Biol. Psychiatry

    (2002)
  • R. Reddy et al.

    Reduced plasma antioxidants in first-episode patients with schizophrenia

    Schizophr. Res.

    (2003)
  • T.N. Srinivasan et al.

    Smoking in schizophrenia—all is not biological

    Schizophr. Res.

    (2002)
  • M.L. Steinberg et al.

    Applicability of the Fagerstrom Test for Nicotine Dependence in smokers with schizophrenia

    Addict. Behav.

    (2005)
  • M.C. Aguilar et al.

    Complex interactions between nicotine dependence and symptoms in schizophrenia: a naturalistic study

    Br. J. Psychiatry

    (2005)
  • T.A. Al-Habeeb et al.

    Smoking among male psychiatric outpatients in Saudi Arabia

    Ann. Saudi Med.

    (2000)
  • F. Arias-Horcajadas et al.

    Consumo y dependencia de drogas en la esquizophrenia

    Actas Luso Esp. Neurol. Psiquiatr.

    (1997)
  • N.L. Benowitz

    Pharmacologic aspects of cigarette smoking and nicotine addiction

    N. Engl. J. Med.

    (1988)
  • N.L. Benowitz et al.

    Ethnic differences in N-glucuronidation of nicotine and cotinine

    J. Pharmacol. Exp. Ther.

    (1999)
  • N. Breslau et al.

    Nicotine dependence in the United States: prevalence, trends and smoking persistence

    Arch. Gen. Psychiatry

    (2001)
  • S. Brown et al.

    The unhealthy lifestyle of people with schizophrenia

    Psychol. Med.

    (1999)
  • M. Calabresi et al.

    La prevalenza del fumo di tabacco nei pazienti psichiatrici

    Minerva Psichiatr.

    (1991)
  • A. Campo et al.

    Prevalencia de consumo de cigarrillo en pacientes de la consulta psiquiátrica de Bucaramanga

    Colomb. Med.

    (2004)
  • A. Campo-Arias et al.

    Tabaquismo en pacientes psiquiátricos ambulatorios

    Revista ABP-APAL

    (1998)
  • A. Campo-Arias et al.

    Severidad del tabaquismo en pacientes de la consulta psiquiátrica

    Rev. Argent. Psiquiatr. Biol.

    (1999)
  • A. Campo-Arias et al.

    Anxiety and depressive symptoms among smokers: a population study

    Medunab

    (2004)
  • R.S. Caraballo et al.

    Racial and ethnic differences in serum cotinine levels of cigarette smokers

    JAMA

    (1998)
  • C. Carvajal et al.

    Prevalencia del consumo de cigarrillos en pacientes psiquiatricos

    Acta Psiquiatr. Psicol. Am. Lat.

    (1989)
  • G. Casella et al.

    Statistical Inference

    (2002)
  • Centers for Disease Control and Prevention (CDC)

    Cigarette smoking among adults—United States, 1992, and changes in the definition of current cigarette smoking

    MMWR

    (1994)
  • Centers for Disease Control and Prevention (CDC)

    Cigarette smoking among adults—United States, 1993

    MMWR

    (1994)
  • Centers for Disease Control and Prevention (CDC)

    State-specific prevalence among adults of current cigarette smoking and smokeless tobacco use and per capita tax-paid sales of cigarettes—United States, 1997

    MMWR

    (1998)
  • Centers for Disease Control and Prevention (CDC)

    State-specific prevalence of current cigarette smoking among adults, and policies and attitudes about secondhand smoking—United States, 2000

    MMWR

    (2001)
  • G.B. Challis

    Level of activity and prevalence of smoking in psychiatric patients

    Can. J. Psychiatry

    (1999)
  • J.A. Chiles et al.

    Smoking and schizophrenic psychopathology

    Am. J. Addict.

    (1993)
  • S.A. Chong et al.

    Smoking among Chinese patients with schizophrenia

    Aust. N. Z. J. Psychiatry

    (1996)
  • M.A. Corrao et al.

    Tobacco Control Country Profiles

    (2000)
  • L.S. Covey et al.

    Ever-smoking, quitting, and psychiatric disorders: evidence from the Durham, North Carolina, and Epidemiological Catchment Area

    Tob. Control

    (1994)
  • Cytel Software Co.

    Logxact-4 User Manual

    (2000)
  • G.W. Dalack et al.

    Nicotine dependence in schizophrenia: clinical phenomena and laboratory findings

    Am. J. Psychiatry

    (1998)
  • J. de Leon

    Smoking and vulnerability for schizophrenia

    Schizophr. Bull.

    (1996)

    • Cited by (0)

    View full text
    Copyright © 2005 Elsevier B.V. All rights reserved.