A study led by Johns Hopkins investigators has shown
that women with a serious caffeine habit and a family
history of alcohol abuse are more likely to ignore advice
to stop using caffeine during pregnancy. Withdrawal
symptoms, functional impairment and craving were cited by
the women as reasons they could not cut out or cut back on
caffeine use.
None of the women had a current alcohol use diagnosis,
and none had been treated for alcohol problems.
"Results of this study suggest that genetic
vulnerability reflected in a family history of alcoholism
may also be at the root of the inability to stop caffeine
use," said co-lead author Roland R. Griffiths, a professor
in the departments of
Psychiatry and
Neuroscience at the School of Medicine.
The study appears in the December issue of the
American Journal of Psychiatry.
Griffiths, whose past studies of caffeine use helped
establish the drug's addictive nature, collected data on
caffeine and alcohol use from 44 pregnant women seeking
prenatal care from a private obstetrics and gynecology
practice in a suburban community. Results showed that half
the women who had both a lifetime history of caffeine
dependence and a family history of alcoholism ignored their
doctor's recommendation to abstain from caffeine use and
consumed caffeine in amounts greater than those considered
safe during pregnancy.
Women in the study without these dual risk factors
were able to abstain from caffeine during pregnancy,
Griffiths said.
"This study helps to validate the diagnosis of
caffeine dependence as a clinically significant
phenomenon," Griffiths said. "It's one thing to speculate
how powerful the dependence is, but here we have an example
of people who are not following physician recommendations
and are unable to quit caffeine in spite of wanting to do
so."
Caffeine use during pregnancy has been associated with
a variety of adverse consequences, including spontaneous
abortion and reduced fetal growth. Government health
agencies in the United States, Canada and the United
Kingdom have issued health warnings about limiting the use
of caffeine during pregnancy. The U.S. Food and Drug
Administration has advised pregnant women to "avoid
caffeine-containing foods and drugs, if possible, or
consume them only sparingly," and Health Canada and the
Food Standards Agency of the United Kingdom have advised
that pregnant women consume less than 300 milligrams per
day of caffeine, according to the study.
Co-lead author Dace S. Svikis, a part-time associate
professor in the Department of Psychiatry and Behavioral
Sciences, emphasized the clinical implications of the study
for pregnancy and other medical conditions for which
caffeine use is not recommended. "While the majority of
women in the study reduced their caffeine intake throughout
pregnancy, the subgroup of women with both risk factors
appears to require intervention in addition to instructions
from their physician in order to assure caffeine
abstinence," Svikis said. Svikis is also a professor of
psychology at Virginia Commonwealth University.
Caffeine is the most widely used mood-altering drug in
the world, with 80 percent to 90 percent of children and
adults in North America regularly consuming
caffeine-containing foods. Mean daily caffeine consumption
among adult caffeine consumers in the United States has
been estimated to be 280 milligrams per day, which is
equivalent to about three six-ounce cups of coffee or five
16-ounce bottles of cola soft drink, according to the
study.
For the Hopkins-led study, a lifetime diagnosis of
caffeine dependence was established using criteria listed
in the fourth edition of the Diagnostic and Statistical
Manual of Mental Disorders. The DSM IV, published by the
American Psychiatric Association, is the handbook used most
often in diagnosing mental disorders in the United States
and internationally, Griffiths said.
Patients were evaluated as having a family history of
alcoholism if they reported at least one first-degree
relative who met the Family History Research Diagnostic
Criteria for alcoholism. The FH RDC has high reliability
and validity for diagnoses of alcoholism in first-degree
relatives.
Subjects had a mean age of 31.9 years, 96 percent were
Caucasian, 100 percent were married, 50 percent had a
four-year college degree, and 23 percent reported having an
advanced degree.
Fifty-seven percent had a lifetime diagnosis of
caffeine dependence, and 52 percent reported having a
family history of alcoholism. Thirty-two percent had both
risk factors, and 23 percent had neither.
On the first prenatal visit, the patients were asked
to complete a questionnaire that assessed caffeine,
tobacco, alcohol and other drug use during the six months
before pregnancy awareness and during the seven days before
the first prenatal visit. Each patient also met with the
obstetrician for prenatal counseling. As part of the
counseling session, the physician stated that caffeine use
during pregnancy is associated with a variety of adverse
consequences and that his recommendation was for the woman
to eliminate all caffeine use for the duration of her
pregnancy.
Three follow-up questionnaires — at two to
three, three to four and seven months after conception
— were conducted to assess changes in caffeine and
other substance use since the last visit. In each of these
meetings, women were also asked to provide saliva samples
to test for caffeine use.
In addition, diagnostic interviews were conducted by a
licensed clinical psychologist between the second and third
questionnaire assessments. The interviews required 60 to 90
minutes and consisted of the Structured Clinical Interview
for DSM III R (SCID, axis I) and the Family Alcohol and
Drug Survey.
The SCID is a reliable and valid semi-structured
diagnostic interview that is used to assess mood disorders,
schizophrenia and other psychotic disorders, anxiety
disorders, substance-related disorders, somatoform
disorders and eating disorders, Griffiths said. For this
study, the SCID included a section that permitted diagnosis
of psychoactive substance-use disorders including caffeine
dependence.
The Family Alcohol and Drug Survey is a
semi-structured interview that was developed for use in a
twin and family study of alcoholism.
It has been well established that family members of
people with alcoholism are more likely to be alcohol
dependent, Griffiths said.
Studies involving adopted children and identical twins
have suggested that genetic factors play a role in alcohol
and drug dependency within families. Twin studies have also
demonstrated genetic factors in relation to problematic
caffeine use, including heavy caffeine use, caffeine
tolerance and caffeine withdrawal, Griffiths said.
With regard to a link between alcoholism and caffeine,
there is a high co-occurrence between alcoholism and
caffeine use, and twin studies examining alcohol use,
caffeine use and cigarette smoking concluded that a common
genetic factor underlies the use of these three
substances.
Svikis said women with a lifetime diagnosis of
caffeine dependence and a family history of alcoholism also
reported higher rates of past cigarette smoking and
problematic alcohol use. "This suggests that caffeine
dependence may be a useful marker for risk of dependence on
other drugs of abuse. It could be used to identify people
who could be at high risk and need special care and
treatment," Svikis said.
The small number of subjects and the homogeneous
nature of the population are limitations of the study;
Griffiths said that replicating the study using a larger
and more heterogeneous group of subjects would be
valuable.
This study was supported by grants from the National
Institute on Drug Abuse and the National Institute on
Alcoholism and Alcohol Abuse.
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