A new European study has found that EPO (erythropoietin) — best known as a performance-enhancing drug in sport — may improve cognitive functioning in patients suffering from bipolar disorder or depression.
Most people think of disorders such as bipolar disorder and depression as conditions which affect mood, but in reality they also affect cognitive function — how quickly and how well a brain functions. Researchers estimate hundreds of millions of patients throughout the world suffer from suppressed cognitive function.
The findings, presented at the European College of Neuropsychopharmacology conference in Vienna, increase hope for treatment for this problem.
The hormone EPO, mostly produced by the kidney, is essential for the production of red blood cells. EPO gives the blood a greater capacity to carry oxygen, and it is this characteristic which makes it attractive as a performance-enhancing drug.
As many may remember, the cyclist Lance Armstrong admitted to using EPO to improve physical performance, and many other professional athletes have faced sanction when testing positive for the substance. Medically, recombinant EPO is used for the treatment of anemia.
A slowdown in thinking can have serious effects on sufferers, making it more difficult to retain a job, pass an exam, or maintain a relationship. In the new study a group of Danish scientists discovered that EPO can help restore cognitive function in patients suffering from these mental disorders.
In two randomized controlled trials, the researchers assessed cognitive function in 79 patients suffering from depression or bipolar disorder. They assigned 40 of the patients to be given EPO for nine weeks, with the remaining 39 being given a placebo.
They found that EPO had beneficial effects on patients’ completion of a range of cognitive tests, including tests on verbal memory, attention span, and planning ability. Tests showed that this improvement was maintained for at least six weeks after treatment finished (the longest follow-up time in the trials).
Lead researcher Dr. Kamilla Miskowiak said, “EPO treated patients showed a five times greater cognitive improvement from their individual baseline levels compared with placebo treated patients. EPO-treated patients showed 11 percent improvement while placebo treated patients improved only by two percent. This effect of EPO on cognition was maintained six weeks after patients had completed their treatment.”
In an interesting twist, it was found that patients who performed poorly in neuropsychological tests showed remarkably greater cognitive benefits when given EPO.
Said Miskowiak, “This is interesting, as it means that we may be able to target patients for EPO treatment — and perhaps other future cognition treatments — based on how they do on neuropsychological tests.”
“We need bigger studies to confirm that the effects we have seen can be replicated, to confirm dosage, frequency of use and so on. EPO is already used medically, so we know quite a lot about safety. Although EPO is generally safe if patients’ red blood cell levels are controlled regularly, there are certain groups for whom the risk of blot clots is too high — for example people who smoke or who have previously had blood clots.
“So although these results hold out great promise, EPO treatment is not ready to be rolled out as a treatment just yet and may not be for everyone.”
The WHO estimates that around 350 million people suffer from depression, with a further 60 million suffering from bipolar disorder, but the drugs normally used to treat depression and bipolar disorders don’t have any major effect on cognition.
Experts believe that up to 70 percent of patients in remission from bipolar disorder, and up to 40 percent in remission from depression continue to have cognitive problems. Currently there is no available effective treatment to target cognitive problems in these patients.