Sex differences, puberty and insomnia

Periods bring on sleepless nights:

Adolescent girls appear to be at greater risk of insomnia after they begin menstruation, a study has found.

This suggests that hormonal changes play a role in developing the sleep disorder, the researchers say in the journal Pediatrics.

Researchers found that among more than 1000 13- to 16-year-olds in the study, nearly 11% had suffered insomnia at some point.

Insomnia, based on formal clinical criteria, was defined as problems falling asleep or staying asleep at least four times a week for a month or longer.

Typically, the study found, the teens started having sleep disturbances around the age of 11.

Before menstruation, girls were about as likely as boys to have insomnia.

But after they began their menstrual periods girls had more than twice the risk of insomnia as boys.

The findings suggest that the hormonal changes that come with menstruation contribute to girls' insomnia risk, according to the authors.

Such a physiological reason is one of two broad explanations for why menstruation would be related to insomnia, says lead author Dr Eric Johnson.

The other possibility is that the physical changes that come with puberty, like breast development, create "social pressures" that contribute to sleep problems, says Johnson, a researcher with RTI International.

But he says menstruation is related specifically to problems with staying asleep and getting enough deep sleep.

These forms of insomnia are more likely to have physiological causes, whereas problems with falling asleep in the first place can often be stress-related.

In addition, girls' higher risk of insomnia was not explained by higher rates of depression, which is often marked by sleep disturbances.

A long lasting problem

Another key finding, Johnson says, is that of all teens who ever suffered insomnia, 88% also had symptoms at the time of the study.

This, he says, signals that the problem is lasting for many teenagers.

"Insomnia seems to be common and chronic among adolescents," Johnson and his colleagues conclude.

Given the consequences of sleep deprivation among teenagers, including blunted mental acuity, poorer school performance, and even poorer physical and emotional health, prevention and treatment may need to become "important priorities", the researchers say.

Therapies for insomnia include lifestyle changes to promote sleep, like getting to bed and rising at regular times each day, cognitive behavioral therapy and sleep medications.

Alternatively, sex steroid hormones may alter the properties of the circadian clock - perhaps decreasing its amplitude along with well-documented delay in phase. As they always say "More research needs to be done"....