Researchers from RCSI and Beaumont Hospital have conducted a study which has found striking brain similarities in bipolar disorder and schizophrenia.

The research has also pinpointed for the first time that a process which controls how information is transmitted from neuron to neuron in the brain is altered in both conditions and may potentially contribute to the developments of improved treatments in the future.

The study was the first to look at sub-regions in the part of the brain known as the hippocampus. Abnormalities in the hippocampus are among the most consistent findings in schizophrenia research and are also implicated in bipolar disorder. Certain areas of the hippocampus (cornu ammonis regions 2 and 3) were found to be different, in terms of how their proteins are affected, in people with schizophrenia and bipolar disorder compared to the general population. The differences observed in these regions were found to be almost identical in both conditions. A process which controls how information is transmitted by the shuttling of proteins to and from the synapse (a junction that permits a neuron to pass a signal to another cell) was also found to be is affected in both illnesses.

Professor David Cotter, Department of Psychiatry, RCSI and Beaumont Hospital, commented: “Our study is the first to show the depth of protein similarities between schizophrenia and bipolar disorder as they appear in the brain and the processes associated with them. Although, the two conditions present with different symptoms, the research has shown that they are almost identical in terms of how they present in the brain.”

There are over 40,000 people in Ireland diagnosed with bipolar disorder, with many more affected by the illness that are undiagnosed. Approximately 45,000 people in Ireland are affected by schizophrenia.

Dr Melanie Föcking, Department of Psychiatry, RCSI was the lead author on the study and worked with colleagues Mr Patrick Dicker, Department of Epidemiology and Public Health, RCSI; Dr Jane English, Dr Oliver Schubert and senior author Professor David Cotter (also Department of Psychiatry, Beaumont Hospital); in collaboration with Professor Michael Dunn, Conway Institute of Biomolecular and Biomedical Research, University College Dublin.

The study is the first of its kind to use a process of laser assisted micro dissection which enabled the researchers to pinpoint the altered proteins to specific subregions in this part of the brain.

The research was published in the highest ranking Psychiatry Journal, Archives of General Psychiatry, and the research team was funded by the Wellcome Trust, The Brain and Behavior Research Foundation (formerly NARSAD), and the Stanley Medical Research Institute.