Psychiatric Comorbidity of Smoking and Nicotine Dependence: An Epidemiologic Perspective Naomi Breslau, Ph.D. Department of Epidemiology Michigan State

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: [email protected]

A recent report in the JAMA called

attention to the observation that smokers

are disproportionately persons with mental

illness.

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.

“Persons with a current mental disorder

consumed approximately 44.3% of

cigarettes smoked by the U.S. population.”

(Lasser et al., 2000, JAMA)

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.

Lifetime History of Daily Smoking

“Did you ever smoke daily for one

month or more?”

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.

Lifetime Comorbidity of Daily Smoking

Anxiety disorders OR (95% CI)

GAD 2.4 (1.5, 3.7)

Panic disorder 1.7 (1.1, 2.5)

Agoraphobia 1.6 (1.1, 2.4)

Social phobia 1.4 (1.1, 1.7)

Simple phobia 1.6 (1.2, 2.0)

All significant at p<0.05 (NCS; n=4414)


Affective disorders OR (95% CI)

Depression 1.7 (1.3, 2.2)

Dysthymia 1.7 (1.2, 2.4)




Substance disorders OR (95% CI)

Alcohol abuse 3.3 (2.6, 4.1)

Alcohol dependence 4.0 (3.0, 5.4)

Drug abuse 2.6 (1.5, 4.3)

Drug dependence 3.4 (2.4, 4.9)


Other disorders OR (95% CI)

Conduct disorder 2.2 (1.7, 3.0)

ASPD* 4.3 (2.2, 8.4)

All significant at p<0.05 (NCS; n=4414)*ASPD, antisocial personality disorder


Psychiatric disorders OR (95% CI)

Any anxiety dx 1.5 (1.3, 1.8)

Any affective dx 1.8 (1.4, 2.2)

Any substance dx 3.2 (2.6, 4.0)


Although depression and anxiety

predominate in females, the strength of

the associations with smoking is similar in

both sexes.

Conversely, although substance use disorders

are more prevalent in males than females, the

strength of the associations with smoking varies

little between the sexes.

The associations of psychiatric disorders

with tobacco dependence are stronger than

with non-dependent smoking.

Dependent smokersOR (95% CI)

Non-dependent OR (95% CI)

Alcohol dependence 2.7 (1.8, 4.0)* 2.1 (1.4, 3.2)*

Cannabis dependence 8.0 (4.3, 14.8)* 4.3 (2.2, 8.2)*

Cocaine dependence 11.8 (4.3, 32.2)* 6.5 (2.2, 19.5)*

Major depression 2.9 (1.9, 4.5)* 1.1 (0.6, 1.8)

Any anxiety 2.4 (1.7, 3.5)* 1.4 (1.0, 2.0)

Associations of Psychiatric Disorders in Dependent and Non-dependent Smokers

*p <0.05 (Southeast Michigan; n = 1007) (Breslau, 1995)Reference group: never daily smokers

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.

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

These three hypotheses are subsumed under the notion of “self medication.”

Accordingly, smoking begins as a successful attempt to relieve painful feelings.

Vulnerable persons find the effects of nicotine

powerfully reinforcing; this occurs before they

develop physiologic dependence;dependent

smokers smoke to avoid withdrawal.

2. Smoking as cause of mental illness

a. Nicotine & other pharmacologic smoking substances effect on brain

b. Smoking lung function (panic dx)

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)

Causality in observational studies?

Temporal order between a

postulated cause and an outcome.

(A necessary condition)

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.

However, evidence that the postulated

“cause” predicts increased risk for

subsequent onset of outcome is often

equivocal.

Time 1 Time 2

Cause Outcome (smoking) (depression)

Confounding(e.g. heritability)

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<0.05 (NCS; n = 4414)

Daily smoking

Nicotinedependence Persistence

Major depression 1.5* 2.0* 0.8

Dysthymia 1.6* 0.9 0.5



Odds Ratios

Daily smoking

Nicotine dependence Persistence

Agoraphobia 1.3 1.8* 1.8

GAD 1.9* 1.8 0.8

Simple phobia 1.6* 1.8* 1.4

Social phobia 1.5* 1.8* 1.3

Panic disorder 0.9 1.8 0.3

PTSD 2.1* 1.7* 0.9


Odds Ratios


Daily smoking

Nicotinedependence Persistence

Alcohol A/D 1.4* 1.8* 0.7

Drug A/D 1.6* 1.7* 0.9

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.

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.

Does smoking increase the risk for

subsequent onset of specific psychiatric

disorders?

Daily Smoking and the Subsequent Onset of Disorders

Subsequent disorder OR (95% CI)

Major depression 3.2 (1.6, 6.5)*

Dysthymia 3.6 (1.8, 7.5)*

Adjusted for race, sex, education, age (Breslau et al., 2004, Psychol. Med.)*p<0.05 (NCS; n = 4414)



Panic disorder 2.6 (1.2, 5.4)*

Agoraphobia 4.4 (2.3, 8.2)*

Simple phobia 1.4 (0.7, 2.8)

Social phobia 1.1 (0.5, 2.4)

GAD 2.7 (0.9, 8.1)

PTSD 1.3 (0.6, 2.9)

Adjusted for race, sex, education, age (Breslau et al., 2004, Psychol. Med.)*p<0.05 (NCS; n = 4414)



Alcohol A/D 3.0 (2.1, 4.4)*

Drug A/D 3.4 (2.1, 5.4)*Adjusted for race, sex, education, age (Breslau et al., 2004, Psychol. Med.)*p<0.05 (NCS; n = 4414)

Risk for dxs in active vs. past smokers

Years sincequitting

Major Depression Not significant Not significant

Dysthymia Not significant Not significant

Panic disorder p<0.05 p<0.05

Agoraphobia p<0.05 p<0.05

Alcohol A/D p<0.05 Not significant

Drug A/D p<0.05 Not significant

Adjusted for race, sex, education, age (Breslau et al., 2004, Psychol. Med.) (NCS; n = 4414)

Proximity of Exposure

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).

Smoking and Depression

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.

Active smoking may be a marker

for other substance use disorders.

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.

Evidence from prospective studies

of smaller samples (not national)

support these findings.

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.

Depressionas cause

Panic dxas outcome

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

Documents

Psychiatric Comorbidity of Smoking and Nicotine Dependence: An Epidemiologic Perspective Naomi Breslau, Ph.D. Department of Epidemiology Michigan State