Psychiatric Comorbidity of Smoking and Nicotine Dependence: An Epidemiologic Perspective

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Psychiatric Comorbidity of Smoking and Nicotine
Dependence An Epidemiologic Perspective

• Naomi Breslau, Ph.D.
• Department of Epidemiology
• Michigan State University
• College of Human Medicine
• email breslau_at_epi.msu.edu

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• A recent report in the JAMA called attention to
  the observation that smokers are
  disproportionately persons with mental illness.

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• The connection between smoking and substance
  abuse has a long history. However, the
  association between smoking and mental disorders
  has been recognized since approximately 1990.

4

• Persons with a current mental disorder consumed
  approximately 44.3 of cigarettes smoked by the
  U.S. population.
• (Lasser et al., 2000, JAMA)

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National Comorbidity Survey (NCS)

• A representative sample of 8,098 persons 15-54
  years of age in the U.S. surveyed in 1990 -
  1992.
• Information on smoking was gathered in a
  representative subset of 4,414.

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Lifetime History of Daily Smoking

• Did you ever smoke daily for one month or more?

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Lifetime Comorbidity of Smoking and Disorders

• The odds ratio estimates smokers risk for a
  specific DSM-IIIR disorder relative to persons
  who never smoked daily.

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Lifetime Comorbidity of Daily Smoking
All significant at p 9
Lifetime Comorbidity of Daily Smoking
All significant at p 10
Lifetime Comorbidity of Daily Smoking
All significant at p 11
Lifetime Comorbidity of Daily Smoking
All significant at pn4414)ASPD, antisocial personality disorder
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Lifetime Comorbidity of Daily Smoking
All significant at pn4414)
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• Although depression and anxiety predominate in
  females, the strength of the associations with
  smoking is similar in both sexes.

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• Conversely, although substance use disorders are
  more prevalent in males than females, the
  strength of the associations with smoking varies
  little between the sexes.

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• The associations of psychiatric disorders with
  tobacco dependence are stronger than with
  non-dependent smoking.

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Associations of Psychiatric Disorders in
Dependent and Non-dependent Smokers
p (Southeast Michigan n 1007) (Breslau,
1995) Reference group never daily smokers
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Potential Explanations for Smoking-Mental
Illness Association

• 1. Mental illness as cause of smoking.
• 2. Smoking as cause of mental illness.
• 3. Common predispositions to both
• smoking and mental illness.

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1. Mental illness as cause of smoking a.
Mental illness smoking initiation b.
Mental illness progression to regular
smoking and
dependence c. Mental illness reduced
capacity to quit
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• These three hypotheses are subsumed under the
  notion of self medication.
• Accordingly, smoking begins as a successful
  attempt to relieve painful feelings.

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• Vulnerable persons find the effects of nicotine
  powerfully reinforcing this occurs before they
  develop physiologic dependencedependent smokers
  smoke to avoid withdrawal.

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• 2. Smoking as cause of mental illness
  a. Nicotine other pharmacologic
• smoking substances effect on
  brain
• b. Smoking lung function (panic
  dx)

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• 3. Correlated liabilities for both smoking
  disorder
• a. Low self esteem
• b. Associating with peers who smoke
• and have behavior problems
• c. Shared genetic predisposition
• (e.g. for impulsivity)

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• Causality in observational studies?

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• Temporal order between a
• postulated cause and an outcome.
• (A necessary condition)

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• Evidence that a postulated cause
• (e.g. smoking) does not predict subsequent
  outcome (e.g. depression) can be used to rule
  out a causal explanation.

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• However, evidence that the postulated cause
  predicts increased risk for subsequent onset of
  outcome is often equivocal.

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• Time 1 Time 2
• Cause Outcome
• (smoking) (depression)
• Confounding
• (e.g. heritability)

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Preexisting Disorders Risk for Daily Smoking,
Nicotine Dependence, Persistence (vs.
quitting) Odds Ratios
Adjusted for race, sex, education, age
(Breslau et
al., 2004, Biol. Psych.)p (NCS
n 4414)
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Preexisting Disorders Risk for Daily Smoking,
Nicotine Dependence, Persistence (vs.
quitting) Odds Ratios
Adjusted for race, sex, education, age
(Breslau et al.,
2004, Biol. Psych.) p (NCS n 4414)
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Preexisting Disorders Risk for Daily Smoking,
Nicotine Dependence, Persistence (vs.
quitting) Odds Ratios
Adjusted for race, sex, education, age
(Breslau et
al., 2004, Biol. Psych.)p (NCS
n 4414)
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• The role of psychiatric disorders varied across
  stages of smoking it played a role in onset of
  daily smoking and progression to dependence, but
  not in quitting.

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Active vs. Past (remitted) Disorders

• The majority of preexisting disorders, when
  active, predicted the subsequent onset of daily
  smoking and smokers progression to dependence.
• In contrast, remitted disorders did not predict
  subsequent smoking.

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• Does smoking increase the risk for subsequent
  onset of specific psychiatric disorders?

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Daily Smoking and the Subsequent Onset of
Disorders
Adjusted for race, sex, education, age
(Breslau et al., 2004, Psychol. Med.) p (NCS n
4414)
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Daily Smoking and the Subsequent Onset of
Disorders
Adjusted for race, sex, education, age
(Breslau et al., 2004, Psychol. Med.) p
(NCS n
4414)
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Daily Smoking and the Subsequent Onset of
Disorders
Adjusted for race, sex, education, age
(Breslau et al., 2004, Psychol. Med.) p (NCS n
4414)
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Proximity of Exposure
Adjusted for race, sex, education, age
(Breslau et al., 2004, Psychol. Med.)
(NCS n 4414)
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Smoking and Depression

• Treatment of smoking is unlikely to
• reduce onset of depression past smokers do
  not differ from active smokers.
• Smoking is unlikely to cause depression.
• Depression and smoking are likely to be
• linked by common predisposition (genetic
  evidence).

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Smoking and Panic Disorder

• Evidence of risk only in one direction
• (smoking panic disorder)
• Active smoking, but not past smoking,
• increases risk.
• In past smokers, there is a decreased risk
• for panic onset with passage of time since
• quitting.

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• Active smoking may be a marker for other
  substance use disorders.

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• These results are based on retrospective data,
  using statistical methods that take into account
  information on age of onset of disorders and age
  of onset of smoking.

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• Evidence from prospective studies of smaller
  samples (not national) support these findings.

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Summary

• 1. Little evidence for influence of depression on
  smoking initiation.
• 2. Support for progression to daily
  smoking/nicotine dependence.
• 3. No support for reduced quitting.
• 1. Increased risk in smokers.
• 2. Potential role for respiratory problems.

Depression as cause
Panic dx as outcome
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Summary

• 1. Smoking and/or alcohol precede(s) use of
  illicit drugs.
• 2. The smoking-illicit drug sequence is more
  common in females.

Smoking, alcohol illicit drugs