Bipolar disorder, also known as manic depression, is a mental health problem characterized by a dramatic shift between extreme mania and deep depression. People with bipolar disorder feel high and become more active and energetic during a manic episode. During a depressive episode, they feel down, hopeless, and tired. Causes of disorder are unknown, but environmental and genetic factors mostly contribute to people.

The research, published in Molecular Psychiatry, recently proved that correlation between bipolar disorder (BD) and Phospholipase Cγ1 (PLCG1), a signaling protein. Researchers affiliated with UNIST, Ulsan National Institute of Science and Technology (UNIST), Republic of Korea, have analyzed behaviors of PLCG1-deficient mice and found that the mice exhibit manic-like behavior. Interestingly, manic activities of PLCG1-deficient mice were reduced after drug treatment for bipolar disorder.

According to the study, inhibitory synapses do not work properly when excitatory neurons lacking PLCG1. That results in the imbalance between excitatory synapses and inhibitory synapses. Then, mental disorder like bipolar disorder occurs.

“After 10 years of research, we have finally revealed PLCγ1 protein plays a major role in the onset of bipolar disorder,” says Professor Pan-gil Suh. “Our findings, therefore, provide evidence that PLCγ1 is critical for synaptic function and plasticity and that the loss of PLCγ1 from the forebrain results in manic-like behavior.”