Kindling as a Cause of Bipolar?

Kindling Phenomenon	Circadian Rhythm
Brain Changes & Imaging	Causes Home

Initial affective episodes in patients with bipolar disorder are often related to psychological stressors, but after several episodes appear to require less and less of a trigger, until finally they begin occurring spontaneously. This is now referred to as the kindling phenomenon in bipolar disorder.

Kindling may contribute to both rapid cycling and treatment-resistant bipolar disorder, as many researchers believe that brain cells that have been involved in an episode once are more likely to do so again, and more cells will become sensitized over time.

What is Kindling?

The term "kindling" was chosen because the process is very similar to that of a log fire. Holding a match to a pile of wood may start a flame that quickly dies out, but repeating this process a number of times will eventually spark a blazing fire. And the more that fire spreads, the more difficult it is to extinguish.

In 1967, Graham Goddard discovered the phenomenon of kindling while studying the learning process in rats. After repeatedly stimulating the rats' brains with a low voltage of electricity, less and less electrical stimulation was required to induce convulsions. He later demonstrated that it is possible to induce kindling chemically as well.

How Does Kindling Work?

When not medicated, people with bipolar disorder normally worsen over time. Kindling is believed to be one of the leading explanations for this.

Perhaps when you experienced your first manic or depressive episode there was a trigger that set it in motion - a stress in your life of some sort to activate the process. This stressor may have been an event in your life, or an illness or even a medication you took. After a few triggered episodes the electrical wiring of your brain changed, became trained to jump into mania or depression with only a small trigger. Over time, your brain becomes even more sensitized until it just sparks into hyper (or hypo) drive for no apparent reason. This is kindling.

It is possible that certain people have a genetic predisposition that puts them at a higher risk for kindling than other people. It is especially important for these people to continue taking their medications to prevent further kindling from taking place.

Bipolar / Epilepsy Link?

Kindling is associated with another disorder - epilepsy. Seizure disorders and epilepsy are believed to be more common in those with bipolar than in the general population. Seizures are caused by nerve cells that fire off abnormal electrical charges. They occur for many different reasons, and take many different forms.

Many of the medications used to treat bipolar are anticonvulsants used in the treatment of epilepsy. The fact that these medications work so well in both disorders has caused a lot of research and speculation on whether or not the two disorders are more closely related than once believed.