Australian scientists have found that women suffering from schizophrenia were less likely to suffer hallucinations or delusions, when the hormone oestrogen was added to their treatment.
The scientists from Monash University in Melbourne suspect that the hormone might possibly enhance the flow of blood to the brain.
For the research the scientists led by Dr. Jayashri Kulkarni, recruited 102 women who had been diagnosed with schizophrenia.
Half of the group were given a patch containing estradiol, the most common form of oestrogen, while the others also wore a patch, but minus any active drugs. Both groups continued taking their normal antipsychotic medication such as Zyprexa.
Over a period of a month, their symptoms and feelings were recorded on a weekly basis and the research team found that the group given estradiol had a greater improvement in psychotic symptoms and were less likely to report other negative changes in their condition.
They experienced a decline in so-called positive symptoms of the disease, which include such things as 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, but over short periods, oestrogen therapy may be useful in women with schizophrenia after childbirth or menopause, when women with the disease are more prone to relapse.
They say it may also be useful during low-oestrogen phases of a woman's menstrual cycle.
The researchers say that the hormone might have a rapid effect on blood flow in the brain, and on the way the brain uses sugar as fuel but longer-term effects, which might actually change the way brain cells communicated with each other, were also a possibility and they suggest that there might be a role for the hormone in other severe mental illnesses.
Schizophrenia affects about 1.1 percent of the population age 18 and older in any given year and is more common in men than in women - it is usually diagnosed in late adolescence or early adulthood but women often have their first episode around five years later than men.
Symptoms seldom occur after age 45 and only rarely before puberty, although cases of schizophrenia in children as young as 5 have been reported.
It is the most complex, chronic and disabling of the major mental illnesses, with no known single cause, though it is suspected that genetic and environmental factors may play a role in some cases - schizophrenia remains an extremely puzzling condition.
People with schizophrenia may hear voices other people don't hear or may believe others are reading their minds, controlling their thoughts, or plotting to harm them.
These experiences are terrifying and can cause fearfulness, withdrawal, or extreme agitation and because many people with schizophrenia have difficulty keeping a job or caring for themselves, the burden on their families and society is significant.
While there are treatments which can relieve many of the disorder's symptoms, most people who have schizophrenia will have life-long residual symptoms.
Women's bodies produce oestrogen in much greater concentrations and it helps, among other things, to regulate the menstrual cycle.... the link between oestrogen and mental illness was first recognised more than a hundred years ago.
Dr. Kulkarni says oestrogen treatment is a promising new area for future treatment of schizophrenia and potentially for other severe mental illnesses.
Mental health charities say any new research that could lead to the development of effective treatments for psychosis is welcome but bigger studies are now called for.
The research is published in the Archives of General Psychi