I just finished reading Kelly McGonigal‘s The Willpower Instinct. It is a fascinating look at the psychology and physiology behind our ability to control our actions. In the book talk below, McGonigal discusses some of the research covered in her book.
But it isn’t willpower I want to write about; it’s what I learned about DOPAMINE. Dopamine is the culprit behind folks with Parkinson’s Disease having movement and balance issues. More precisely, it is the lack of dopamine that poses the problem. Back in May, 2007, when I first began blogging about the brain in order to learn about how it functions, I wrote a post about dopamine.
McGonigal has added to my understanding of dopamine. She describes the neurotransmitter as kicking in in anticipation of a reward. That reward can be anything that makes you feel good.
Dopamine tells the rest of the brain what to pay attention to and what to get our greedy little hands on. A dopamine rush doesn’t create happiness itself–the feeling is more like arousal. We feel alert, awake, and captivated. We recognize the possibility of feeling good and are willing to work for that feeling.
When there is insufficient dopamine, besides impacting movement and balance, the brain’s natural reward system feels a sense of apathy, according to McGonigal. She goes on to say that in Parkinson’s patients, while this state may pass for peacefulness, it is actually depression.
What further fascinated me was her explanation of the potential negative effects of dopamine drug therapy on people with Parkinson’s.
The standard treatment for Parkinson’s disease is a two-drug combo: L-dopa, which helps the brain make dopamine, and a dopamine agonist, which stimulates dopamine receptors in the brain to mimic the action of dopamine. When patients begin drug therapy, their brains are flooded with way more dopamine than they’ve seen in a long time. This relieves the main symptoms of the disease, but also creates new problems that no one expected.
Medical journals are full of case studies documenting the unintended side effects of these drugs.
McGonigal then describes one person who “developed insatiable [food] cravings”, another person who “developed a daily gambling habit”, and yet another who “all of sudden found himself afflicted with an increased appetite, a taste for alcohol, and what his wife called ‘an excessive sex urge’…All of these cases were completely resolved by taking the patients off the dopamine-enhancing drug.”
Essentially, it seems that as with much in life, there needs to be a balance in the amount of dopamine your brain processes.
For more on Parkinson’s and dopamine, see my previous posts: