|Bipolar Spectrum Disorder May Be Underrecognized
and Improperly Treated
A new study supports earlier estimates of the prevalence of bipolar
in the U.S. population, and suggests the illness may be more accurately
characterized as a spectrum disorder. It also finds that many people
with the illness are not receiving appropriate treatment. The study,
published in the May 2007 issue of Archives of General Psychiatry,
analyzed data from the National Comorbidity Survey Replication
(NCS-R), a nationwide survey of mental disorders among 9,282 Americans
ages 18 and older. The NCS-R was funded by the National Institutes
of Health’s National Institute of Mental Health (NIMH).
NIMH researcher Kathleen Merikangas, Ph.D. and colleagues identified
prevalence rates of three subtypes of bipolar spectrum disorder
among adults. Bipolar I is considered the classic form of the illness,
in which a person experiences recurrent episodes of mania and depression.
People with bipolar II experience a milder form of mania called
hypomania that alternates with depressive episodes. People with
bipolar disorder not otherwise specified (BD-NOS), sometimes called
subthreshold bipolar disorder, have manic and depressive symptoms
as well, but they do not meet strict criteria for any specific
type of bipolar disorder noted in the Diagnostic and Statistical
Manual for Mental Disorders (DSM-IV), the reference manual
for psychiatric disorders. Nonetheless, BD-NOS still can significantly
impair those who have it.
The results indicate that bipolar I and bipolar II each occur in
about 1 percent of the population; BD-NOS occurs in about 2.4 percent
of the population. The findings support international studies suggesting
that, given its multi-dimensional nature, bipolar disorder may be
better characterized as a spectrum disorder.
“Bipolar disorder can manifest itself in several different ways.
But regardless of type, the illness takes a huge toll,” said NIMH
Director Thomas R. Insel, M.D. “The survey’s findings reiterate
the need for a more refined understanding of bipolar symptoms,
so we can better target treatment.”
Most respondents with bipolar disorder reported receiving treatment.
Nearly everyone who had bipolar I or II (89 to 95 percent) received
some type of treatment, while 69 percent of those with BD-NOS were
getting treatment. Those with bipolar I or II were more commonly
treated by psychiatric specialists, while those with BD-NOS were
more commonly treated by general medical professionals.
However, not everyone received treatment considered optimal for
bipolar disorder. Up to 97 percent of those who had some type of
bipolar illness said they had coexisting psychiatric conditions,
such as anxiety, depression or substance abuse disorders, and many
were in treatment for those conditions rather than bipolar disorder.
The researchers found that many were receiving medication treatment
considered “inappropriate” for bipolar disorder, e.g., they were
taking an antidepressant or other psychotropic medication in the
absence of a mood stabilizing medication such as lithium, valproate,
or carbamazepine. Only about 40 percent were receiving appropriate
medication, considered a mood stabilizer, anticonvulsant or antipsychotic
“Such a high rate of inappropriate medication use among people
with bipolar spectrum disorder is a concern,” said Dr. Merikangas. “It
is potentially dangerous because use of an antidepressant without
the benefit of a mood stabilizer may actually worsen the condition.”
Merikangas and colleagues speculate that as people seek treatment
for anxiety, depression or substance abuse disorders, their doctors,
especially if they are not mental health specialists, may not be
detecting an underlying bipolar condition in their patients.
“Because bipolar spectrum disorder commonly coexists with other
illnesses, it is likely underrecognized, and therefore, undertreated.
We need better screening tools and procedures for identifying bipolar
spectrum disorder, and work with clinicians to help them better
spot these bipolar symptoms,” concluded Dr. Merikangas.
The National Institute of Mental Health (NIMH) mission is to reduce
the burden of mental and behavioral disorders through research
on mind, brain, and behavior. More information is available at
the NIMH website, http://www.nimh.nih.gov.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.