Thirty people suffering from schizophrenia participated in the study led by Professor Jesper Ekelund. All the participants had been on sickness pension for at least five years. They were randomly divided into two groups, one which received famotidine and one which received placebo.
– Already after one week the symptoms of the patients in the famotidine group started to decrease, and after four weeks of treatment the symptoms had decreased statistically significantly. The patients that participated in the study were also positively disposed towards the treatment, says Professor Ekelund.
All of the patients who took famotidine responded positively to the treatment while the symptoms of those who were on a placebo did not change.
Famotidine has been used for the treatment of heartburn since the 1980s, but at regular dosing, 40 mg daily, famotidine almost does not enter the brain at all, since the brain is protected by the blood-brain barrier.
This study showed that by giving a very large dose of famotidine, 200 mg daily, sufficient amounts of the drug are able to penetrate the so-called blood-brain barrier to affect the histamine system in the brain.
Famotidine works by blocking the histamine H2 receptor. There are important neurons in the brain that use histamine as their primary signaling substance. These neurons have an important role as regulators of other signaling substances.
Since 1963, when the subsequent Nobel prize winner Arvid Carlsson showed that dopamine has a central role in psychosis, the so called dopamine-hypothesis has been central in psychosis.
All presently available medications for psychosis are based around this principle. Since treatment response is all too often incomplete and side effects common, there is still a great, unmet medical need for medications with other mechanisms of action.
– Famotidine shouldn’t be used directly as treatment for schizophrenia until long-term use of a dose of this size has been proved safe. However, our study shows that the histamine system in the brain offers a novel approach to treating psychosis, Ekelund states.
– This should lead to increased efforts by the pharmaceutical industry to develop medications based on this histamine-based mechanism.
The project has been awarded substantial funding, 306,000 USD, from the Stanley foundation for follow-up studies. The research group will replicate the finding through a larger, multinational study in collaboration with Karolinska Institutet in Sweden, where the study is coordinated by professor Jari Tiihonen.