CHICAGO, Aug 4 (Reuters) - Adding estrogen to routine medication helped reduce the number of psychotic symptoms in women with schizophrenia, researchers said on Monday.
Women given an estrogen patch in addition to their other drugs had fewer delusions and hallucinations than those who got a placebo, they said.
"Estrogen treatment is a promising new area for future treatment of schizophrenia and potentially for other severe mental illnesses," Jayashri Kulkarni of The Alfred and Monash University in Melbourne, Australia and colleagues wrote in the journal Archives of General Psychiatry.
Schizophrenia affects about 1.1 percent of the population age 18 and older in any given year, according to the National Institutes of Mental Health.
The disorder is far more common in men than in women and is usually diagnosed in late adolescence or early adulthood. Women with schizophrenia typically have their first episode about five years later than men.
Kulkarni and colleagues wanted to see if estrogen offered a kind of protective effect in women vulnerable to the disease.
They studied the effects of estradiol, a form of estrogen, in 102 women of childbearing age with schizophrenia.
They gave 56 women 100 mg of estradiol each day for 28 days via skin patches; 46 women got placebo skin patches. All took their regular medications, which most commonly included an atypical antipsychotic agent, such as Eli Lilly's (LLY.N) Zyprexa, also known as olanzapine.
At the end of the study, the researchers found that women given estradiol had more improvement in their psychotic symptoms compared with the group that got a placebo.
They also experienced a decline in so-called positive symptoms of the disease, which include things like distorted thinking. But there was no change in negative symptoms, such as social or emotional withdrawal.
The researchers said negative symptoms tend to be more difficult to treat, and a longer study would be needed to show a benefit there.
If given over short periods, they said estrogen therapy may be useful in women with schizophrenia after childbirth or menopause, when women with the disease are more prone to relapse. It may also be useful during low-estrogen phases of a woman's menstrual cycle, they said.
(Editing by Maggie Fox and Eric Walsh)