Until recently a doctor faced with a new psychiatric patient would have found it impossible to distinguish between the clinical symptoms of schizophrenia and manic depression and would have had to wait six months to make a diagnosis.
However, thanks to researchers at Israel's Ben-Gurion University, doctors will now be able to identify different mental illnesses in a day through a simple blood test.
The test, which has great implications for the diagnosis and effective treatment of mental disorders, is the culmination of ten years of research into the effects of the mood-stabilising drug lithium on the functioning of G proteins in the blood. These G proteins (Guanine nucleotide binding proteins) exist in all human cells and are responsible for communicating external signals to the inside of the cell.
Researchers Sofia Schreiber-Avissar and her husband Gabriel Schreiber discovered during extensive testing of the G proteins in patients' white blood cells that the functions and levels of these molecules differed very clearly in acute states of mania, depression, schizophrenia and panic disorder.
The Schreibers, both lecturers in clinical pharmacology and psychiatry, say that there have never before been biochemical cross-diagnostic tests, able to support psychiatric differential diagnosis. The clinical symptoms of diseases, such as schizophrenia and mania are similar, and in the past, psychiatrists could only tell them apart once the symptoms were well advanced.
This matters, Schreiber stressed because "once a patient has suffered schizophrenia, he will suffer irreversible loss. People with manic depressive illness come back to themselves."
The time lost in making a clinical diagnosis means that psychiatrists are less able to treat the illness with suitable drugs during its early stages.
According to a paper in Medicine in 1992, researchers already understood that aberrations in G protein functioning could contribute to diseases including cholera, whooping cough and cancer. However, they only realised later that G proteins are important in nearly all cells and that they could therefore influence a much wider range of diseases.
The Schreibers discovered during tests on several dozen mental patients that manic (psychotic) patients had hyper-functioning of the G protein in their white blood cells. "When they were on lithium, the hyperfunction was normalised," Schreiber said. Similar findings in patients with other disorders led to the clear picture that detailed examination of G protein functioning would make it possible to carry out early diagnosis of mental illness.
They have applied for a patent on the blood test and are looking for outside investment in order to produce a standard diagnostic kit for doctors.