A study found that a hormone commonly used in hormone replacement
therapy and as a form of contraceptive could increase levels of
aggression and anxiety and decrease libidos in women who take the
hormone.
Researchers believe the hormone, medroxyprogesterone (MPA), could
explain the symptoms of mood swings, depression and loss of sex
drive described by some of the women who took the MPA for contraception
purposes and hormone replacement therapy.
In a study, three separate hormone treatments were used to evaluate
any behavioral changes in six female monkeys.
The three treatments were estrogen only, estrogen with natural
progesterone and estrogen with MPA. The researchers focused on changes
in aggression, anxiety and sexual behavior.
Results of the Study
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The monkeys treated with estrogen plus MPA exhibited distinctly
higher levels of aggression and restless behaviors compared
to the monkeys who received estrogen alone or estrogen with
progesterone.
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There appeared to be a significant decrease in sexual behaviors among the
monkeys who were treated with the MPA plus estrogen combination.
From these findings, researchers concluded that MPA with estrogen
might produce a greater affect on the brain’s stress system
than the treatment of natural progesterone.
In order to study the behavioral changes over an extended period
of time, researchers have conducted studies involving observing
aggression, anxiety and sexual behavior changes in monkeys over
the course of 21 days, which is comparable to the monthly cycle
for women taking contraceptives.
Journal
of Clinical Endocrinology and Metabolism June 2004;89(6):2963-72
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