Researchers from the Johns Hopkins
Children's
Center say a group of drugs known as "atypical
antipsychotics" that are commonly used to treat children
with aggression, bipolar disorder and schizophrenia may
trigger insulin resistance, a condition that increases the
risk of developing Type 2 diabetes and heart disease later
in life.
Results of the study linking insulin resistance to the
use of these antipsychotics were presented Oct. 20 during
the annual meeting of the American Academy of Child and
Adolescent Psychiatry in Washington, D.C.
For the study, the Johns Hopkins team evaluated 11
children, some overweight and others obese, who gained
significant amounts of weight (a 10 percent weight
increase) while taking the new-generation, or atypical,
antipsychotic drugs olanzpine, quetiapine and risperidone.
Considerable weight gain is a common side effect of
atypical antipsychotic medications and is also one of the
many factors that can contribute to insulin resistance.
All six children on moderate or high doses of one of
these drugs, and three of five children on low doses, had
evidence of insulin resistance, a condition in which the
body cannot properly use the insulin it produces. This
evidence included hypertension, high levels of
triglycerides, low levels of high-density lipoprotein
cholesterol ("good" cholesterol) and increased levels of
protein in the urine.
"The insulin resistance seen in these children was
greater than what would be expected from weight gain alone,
suggesting there is a factor distinct from excess weight
that directly induces insulin resistance," says the study's
lead author, Mark A. Riddle, director of the division of
Child and Adolescent Psychiatry at the Children's
Center.
In general, this group of new-generation
antipsychotics creates fewer side effects than older drugs
used to treat debilitating psychiatric conditions such as
schizophrenia, Riddle says. The drugs, which balance
certain chemicals in the brain and stabilize mood, have
successfully treated countless numbers of children since
being introduced in the 1990s, he notes.
"Treatments are always a matter of risk and benefit
balance. Clearly these drugs are an important treatment
option. But diabetes and heart disease are serious health
issues, so it's important to further investigate this
apparent relationship between atypical antipsychotics and
insulin production and consumption," he says. "We may need
to re-examine how we are prescribing these drugs to see if
dosage changes can be made to ensure children will continue
to receive the benefits of these medications while not
putting them at risk for developing other health problems
in the future."
Riddle says that if the study's findings are confirmed
by larger follow-up studies, he would expect monitoring of
metabolic side effects to become standard practice among
clinicians prescribing atypical antipsychotics to
children.
Insulin resistance occurs when muscle, fat and liver
cells do not properly use insulin, the hormone produced by
the pancreas that helps cells absorb glucose and provides a
source of energy to the body. The pancreas tries to keep up
with the demand for insulin by producing more. Eventually,
the pancreas cannot keep up with the body's need for
insulin, and excess glucose builds up in the bloodstream.
Excess weight, lack of exercise and a family history of
diabetes all contribute to insulin resistance. The
condition is associated with an increased risk of
developing Type 2 diabetes, heart disease and stroke.
Study co-authors were David Cooke and Helen Courvoisie
from the Johns Hopkins Children's Center.
— Jessica Collins
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