Going on the pill could make teenage girls vulnerable to this

By Mark Waghorn via SWNS

Going on the pill may make teenage girls vulnerable to depression, according to new research.

It increases levels of the stress hormone cortisol - which can lead to mental health problems.

Experiments on young rats found synthetic hormones in oral contraceptives disrupted signaling in the prefrontal cortex.

The neurons lie in an area of the brain that regulates mood - and continues to develop throughout adolescence.

"Birth control has had a major positive impact for women's health and autonomy - so it's not that we’re suggesting adolescents should not take hormonal contraceptives," said senior author Professor Benedetta Leuner.

"What we need is to be informed about what synthetic hormones are doing in the brain so we can make informed decisions - and if there are any risks, then that's something that needs to be monitored.

"Then if you decide to use hormonal birth control, you would pay more attention to warning signs if you knew of any possible mood-related side effects."

An estimated four in ten teenage girls in the US lose their virginity between the age of 15 and 19.

Most use a contraceptive - condoms in particular. Of those using birth control, almost five percent use hormonal contraceptives, also prescribed for acne and heavy periods.

Reproductive health experts consider them good choices because they are safe and highly effective at preventing pregnancy.

But one aspect of their effect on the teenage body remains a mystery - whether and how they modify the developing brain.

The Ohio State University team found lab rodents receiving hormonal contraceptives produced higher levels of the stress hormone corticosterone compared to controls.

It is similar to cortisol in humans. Previous research has associated early adolescent use of hormonal contraceptives with the risk for depression in adulthood.

Learning how birth control affects the developing brain is most important as individuals can weigh the risks and benefits of their reproductive health choices, said Leuner.

Despite their popularity "there isn't a lot known about how hormonal birth control influences the teen brain and behavior," said co-author Professor Kathryn Lenz.

She added: "Adolescence is a crucially under-investigated period of dramatic brain change and dramatic hormonal change that we really haven't understood."

The researchers gave a combination of synthetic estrogen and progesterone typically found in hormonal contraceptives to female rats for three weeks.

It began about a month after they were born, an age equivalent to early adolescence in humans. The drugs disrupted the animals' reproductive cycling.

Birth control products work by stopping ovaries from producing hormones at levels necessary to generate eggs. They also make the womb lining inhospitable for an egg to implant.

Blood samples showed the treated rats were producing more corticosterone than untreated animals, a sign that they were stressed.

And after being subjected to and recovering from an experimental stressor, the treated rats' corticosterone levels remained high.

Their adrenal glands were also larger, suggesting stress hormone production was consistently higher than that of controls.

An analysis of gene activation markers in the prefrontal cortex showed a decrease in excitatory synapses, or connections, in that region of treated rats' brains.

But there was no change to inhibitory synapses - a phenomenon that could set up an imbalance of normal signaling patterns and result in altered behavior.

The loss of only excitatory synapses in the prefrontal cortex has been linked to exposure to chronic stress and depression in previous research.

"What this means for the function of particular circuits, we don't know yet," Lenz said.

"But this gives us a clue of where to look next in terms of what the functional outcomes might be."

The researchers are moving forward with additional studies targeting hormonal contraceptive effects on the brain between puberty and late adolescence.

This is a tricky time to study the developing brain because it is undergoing constant change. The reasons behind the drugs' effects are also an open question.

"These are synthetic hormones, so are they affecting the brain because of their synthetic properties, or are they affecting the brain because they are blocking the naturally produced hormones? It is a difficult question to answer, but an important one," Leuner said.

First author Rachel Gilfarb, a graduate student in Leuner's lab, presented the study at a meeting of the Society for Neuroscience in San Diego.