More than 20 percent of American adults took at least one drug for conditions like anxiety and depression in 2010, according to an analysis of prescription data, including more than one in four women.

The report, released Wednesday by pharmacy benefits manager Medco Health Solutions Inc., found that use of drugs for psychiatric and behavioral disorders rose 22 percent from 2001. The medications are most often prescribed to women aged 45 and older, but their use among men and in younger adults climbed sharply. In adults 20 to 44, use of antipsychotic drugs and treatments for attention deficit hyperactivity disorder more than tripled, and use of anti-anxiety drugs like Xanax, Valium and Ativan rose 30 percent from a decade ago.

The statistics were taken from Medco's database of prescriptions and is based on 2.5 million patients with 24 months of continuous prescription drug insurance and eligibility.

The company said women are twice as likely as men to use anxiety treatments, as 11 percent of women 45 to 65 are on an anxiety medication. Women are also more likely than men to take antipsychotic drugs like Zyprexa, Risperdal, and Abilify, which treat disorders like bipolar disorder and schizophrenia. However, among men 20 to 64, use of the drugs has quadrupled over the last decade.

"There has been a significant uptick in the use of medications to treat a variety of mental health problems; what is not as clear is if more people - especially women, are actually developing psychological disorders that require treatment, or if they are more willing to seek out help and clinicians are better at diagnosing these conditions than they once were," said Dr. David Muzina, a psychiatrist and national practice leader of Medco's Neuroscience Therapeutic Resource Center.

Pharmaceutical companies have also sought and received approvals to market their drugs to larger groups of people.

Drugs for attention deficit hyperactivity disorder are prescribed to boys more often than girls, but adult women now take the drugs more often than men. ADHD prescriptions to adult women grew 2.5 times from 2001. However ADHD prescriptions for children have been declining since 2005.

That reflects a decline in prescriptions for psychiatric and behavioral drugs for children. Medco found that prescriptions of those drugs for children have dropped since 2004, when the FDA warned they were linked to suicidal thoughts when used in people under 19. The company said less than 1 percent of children use antipsychotics drugs, although the figure has doubled since 2001.

In the "diabetes belt" states of Tennessee, Kentucky, Mississippi and Alabama, about 23 percent of people are on at least one psychiatric or behavioral disorder drug. Diabetes is particularly widespread in those states and the condition is associated with higher levels of depression and anxiety disorders. The lowest rate of prescriptions was found in Indiana, Ohio, Wisconsin, and Michigan, where less than 15 percent of people are using those medications.

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