Biochemistry of Bipolar Disorder

Doctor Ellen Leibenluft discusses some of the biochemicals that have been associated with bipolar disorder, including dopamine, serotonin, and glutamate.

There are a number of brain chemical messenger systems that have been implicated in bipolar disorder, certainly dopamine is one. Dopamine, of course, has been implicated in schizophrenia which is characterized by psychosis, when people have hallucinations or delusions [and] kind of lose touch with reality. An important thing to know is that people with bipolar disorder can also become psychotic, either when they’re manic, in which case they tend to have very grandiose sorts of delusions, or when they’re depressed in which case they tend to feel extremely badly about themselves [and] think that terrible things are happening in the world. Given that people with bipolar disorder can sometimes become psychotic, it’s not surprising that dopamine has also been implicated in bipolar disorder. Of course, one pole of bipolar disorder is depression, and we know that serotonin has a good bit to do with the brain mechanisms of depression, so that has also been implicated in bipolar disorder. Recently there has been more interest in glutamate which is the major excitatory neurotransmitter; the one that makes the neurons fire. For example, there’s some preliminary data using Riluzole, which is a medication which damps down glutamate, using that to try to treat bipolar disorder. So chances are that there are a number of neurotransmitter systems that are involved in bipolar disorder. It probably ultimately may be hard to find one that’s not we would say, and the issue is putting all the pieces of the puzzle together.