Florida State University issued the following news release:

Media Perpetuates Unsubstantiated Chemical Imbalance Theory of Depression

The theory that depression is caused by a chemical imbalance is often
presented in the media as fact even though there is little scientific
evidence to support it, according to a new study co-authored by a
Florida State University visiting lecturer.

Jeffrey Lacasse, an FSU doctoral candidate and visiting lecturer in the
College of Social Work, and Jonathan Leo, a neuroanatomy professor at
Lincoln Memorial University in Tennessee, found that reporters who
included statements in news articles about depression being caused by a
chemical imbalance, or a lack of serotonin in the brain, were unable to
provide scientific evidence to support those statements.

Lacasse and Leo spent about a year in late 2006 and 2007 monitoring the
daily news for articles that included statements about chemical
imbalances and contacting the authors to request evidence that supported
their statements. Several reporters, psychiatrists and a drug company
responded to the researchers’ requests, but Lacasse and Leo said they
did not provide documentation that supported the chemical imbalance
theory. Their findings were published in the journal Society.

“The media’s presentation of the theory as fact is troublesome because
it misrepresents the current status of the theory,” Lacasse said. “For
instance, there are few scientists who will rise to its defense, and
some prominent psychiatrists publicly acknowledge that the serotonin
hypothesis is more metaphor than fact. As the current study documents,
when asked for evidence, reporters were unable to cite peer-reviewed
primary articles in support of the theory.”

Moreover, the researchers said, several of the responses received from
reporters seem to suggest a fundamental misunderstanding of the theory’s
scientific status. The “Diagnostic and Statistical Manual of Mental
Disorders,” which almost all psychiatrists use to diagnose and treat
their patients, clearly states that the cause of depression and anxiety
is unknown, according to Lacasse and Leo.

The Society article builds on the pair’s 2005 study, which focused on
pharmaceutical advertisements that claim depression is caused by an
imbalance of serotonin — an imbalance the drug companies say can be
corrected by a class of antidepressants called Selective Serotonin
Reuptake Inhibitors (SSRIs).

“The chemical imbalance theory, which was formulated in the 1960s, was
based on the observation that mood could be artificially altered with
drugs, rather than direct observation of any chemical imbalances,” Leo
said. “Since then there has been no direct evidence to confirm the
theory and a significant number of findings cast doubt on the theory.”

The researchers said the popularity of the theory is in large part based
on the presumed efficacy of the SSRIs, but they say that several large
studies now cast doubt on this efficacy. A review of a full set of trial
data published in the journal PLoS (Public Library of Science) Medicine
last month concluded that much of the perceived efficacy of several of
the most common SSRIs was due to the placebo effect. Other studies
indicate that for every 10 people who take an SSRI, only one to two
people are truly receiving benefit from the medication, according to
Lacasse and Leo.

Still, the National Center for Health Statistics found that
antidepressants are the most prescribed drugs in the United States, with
doctors writing more than 31 million prescriptions in 2005. Both Lacasse
and Leo emphasized the importance of patients being given factual
information so they can make informed decisions about medications and
the role of other potentially useful interventions, such as
psychotherapy, exercise or self-help strategies.

“Patients might make different choices about the use of medications and
possibly use alternative approaches to their distress if they were fully
informed,” Lacasse said. “We believe the media can play a positive role
by ensuring that their mental health reporting is congruent with
scientific literature.”