91av

Melbourne

BAD-TEMPERED? Nervous? Easily reduced to tears? If you are a man, you could
be suffering from irritable male syndrome.

This newly recognised condition plays havoc with male animals, temporarily
turning confident, chest-beating Tarzans into withdrawn, grumpy wimps. And
there’s some evidence that irritable male syndrome, which is triggered by a
sudden drop in testosterone, affects men as well as animals, says Gerald Lincoln
of the Medical Research Council’s Human Reproductive Sciences Unit in
Edinburgh.

The symptoms may resemble those of the so-called male menopause, but Lincoln
believes the condition can affect men of any age when stress causes testosterone
levels to plummet. If he’s right, it’s not just women who have their hormonal
ups and downs.

Lincoln first pinpointed the syndrome in Soay sheep. In the autumn, the rams’
testosterone levels soar and they rut. In the winter, testosterone levels
plummet and they lose interest in sex. High testosterone is supposed to mean
more aggression. But the rams were more likely to injure themselves when
testosterone was low.

So Lincoln monitored the activity of eight rams, such as how often they
struck out with their horns. As testosterone levels fell, the rams changed from
competent males who addressed each other in a ritualistic fashion, to nervous,
withdrawn animals that struck out irrationally, he says.

Red deer, reindeer, mouflon and Indian elephants also show clear signs of
irritable male syndrome when testosterone levels fall off at the end of their
breeding seasons, says Lincoln. “The mahouts sometimes starve the elephants
after the must, or tie them up to keep them under control.”

But what does this mean for people? Here the evidence is shaky, Lincoln
admits. But it’s clear that testosterone has a major impact on human behaviour.
The brain is loaded with receptors for testosterone and its conversion products.
What’s more, Richard Anderson, also at Edinburgh, has found that when men who
cannot produce testosterone come off hormone replacement therapy, they become
irritable and depressed. Their mood improves when they resume treatment.

Lincoln thinks that stresses such as bereavement, divorce or life-threatening
illnesses could send testosterone levels plummeting. There are few human studies
on stress and testosterone, he says, but numerous studies on animals, including
primates, show that testosterone levels fall when stress sends corticosteroid
levels skywards.

“It’s right on the money,” says reproductive endocrinologist David Abbott of
the Wisconsin Regional Primate Research Center in Madison. “Testosterone effects
have been missed. When a bloke gets grumpy and irritable, [researchers] try and
explain it only in terms of cortisol levels and depression. They ignore the fact
that testosterone levels are probably falling too.”

But David Handelsman, an expert on male hormones at the University of Sydney,
is more cautious. He says the changes in testosterone levels in normal adult men
are far smaller than the dramatic swings seen in Soay rams, with one notable
exception: levels fall by at least 90 per cent in men who undergo castration for
advanced prostate cancer. “The wives notice it first,” says Keen-Hun Tai of the
Peter MacCallum Cancer Institute in Melbourne. “The men become more withdrawn,
but more emotional. They laugh and cry more easily.”

Clearly, the jury’s still out when it comes to people. But if irritable male
syndrome does affect men, diagnosing it won’t be easy. It’s far from clear what
normal testosterone levels are
(see 91av, 22 July 2000, p 36),
while extra doses of the hormone may increase the risk of heart disease.

But the syndrome could still be worth investigating. “Instead of putting
stressed men on Prozac, a little testosterone may do the job,” says Abbott.