Bipolar Disorder: Causes and Research

What is bipolar disorder?

You have probably heard of bipolar disorder in popular culture or may even know someone who suffers from this affliction. The diagnosis is getting common due to better surveillance and understanding in the psychiatric physician community. Disease statistics being relatively well reported in the U.S, it has been estimated that approximately 3% of the U.S. population suffers from this disorder.

This is by no means the true scope of the problem and is definitely one of the “Iceberg” problems that epidemiologist talk about. The small number of people that are clinically diagnosed are just the tip of a very large undiagnosed population with the reason being quite obviously the stigma attached with the disease.  And that, does affect the chances of diagnosis, as the stigma alone prevents people who could benefit from care from seeking it.

Technically the problem is referred to as a “Manic-Depressive Disorder” and is a situation wherein the patient moves from one extreme of energy and mood to another over variable lengths of time. The key feature of the “manic” state can be characterised by euphoria, grandiose thinking (“I can do ANYTHING”), excessive physical energy, lack of sleep, poor nutritional intake and poor judgment. The depressive mood swings look like just the negative image of the manic swings. There’s no fixed time pattern and a person can be manic for weeks followed by months of depression. The only thing that is constant is the cycling between the two states or a combination of the two.

What causes bipolar disorder?

A lot of clinical and neuro-biological research is going into bipolar disease with an increasing number of people being diagnosed and so has funding increased for research on root level causes and treatments.

Most physicians and neuroscientists will agree that there isn’t a single trigger for the problem with many factors probably interacting and leading to the illness.

Genetic history of the disease in the family seems to be important as bipolar disorder tends to run in families. A child with a parent or sibling who has bipolar disorder is much more likely to get it as compared to children without a family history. But, it is important to remember that most children with a family history of bipolar disorder will not develop the illness. A family history does not doom a patient to the disease.

Technological and engineering advances in gene research are helping uncover a wealth of knowledge about bipolar disease. There exists a bipolar disorder phenomena database which is funded in part by the NIMH (The National Institute of Mental Health, USA) and this database can be used by scientists to link visible signs of the disorder with the gene sequences that play a role in their development.

Scientists are also using another tack for research by studying illnesses with similar symptoms, like depression and schizophrenia. Again, the idea is to identify genetic differences that may increase a person's risk for developing bipolar disorder. Finding these genetic “hotspots" or “loci” (a certain region in the genetic code) should eventually help explain how environmental factors can affect the development of the disease.

Before we go further it should be noted that genes are not the only risk factor. Studies of identical twins have shown that the twin of a person with bipolar illness doesn’t always develop the disorder. Theoretically, if it were a purely genetic disease, the twin should get it as well, since they share an identical copy of their genes between them and the evidence just goes to show that factors besides genes have a role as well.

Brain structure and functioning in bipolar disorder

Recent advents in imaging technology, namely, fMRI (functional Magnetic Resonance Imaging) and PET scans (Positron Emission Tomography) have changed our level of knowledge by a quantum leap.

These new technologies have given us the ability to look at a person’s brain while it is awake and functioning. Measuring the neuro-chemical and electrical differences between a normal brain and one suffering from bipolar disease gives us huge amounts of real data on what structural and functional changes have happened to the brain of someone who suffers from this problem.

The connections between different regions of the brain seem to be quite important for shaping and coordinating functions such as forming memories, learning, and emotions. Unfortunately, neuroscience still has very limited knowledge of how different parts of the human brain connect and interact.

In our next article we will get into the bones of the issue and learn about some of the recognizable symptoms of bipolar disorder and its treatment.