Wednesday, 3 April 2013

Our brain is more than a bag of chemicals

In the Western world, there are an increasing number of people who suffer from mental diseases. Some statistics say that about one in three people fall mentally ill once throughout their lifetime. Many of them take psychotropic drugs. However, often this medication does not help or has severe side effects. Why are mental diseases so different from diseases of the body?

In a TED Talk, biologist David Anderson from California Institute of Technology explains why. He says that we have an oversimplified image of psychiatric disorders: we consider them to be caused by chemical imbalances in the brain. The drugs we take changes the chemistry in the brain. They may improve the patient’s symptoms, but they have many side effects as they act in a very unspecific way. A more recent view of psychiatric diseases is that they are disorders of emotion circuit function. Certain areas of the brain are affected, but not all of them. Therefore, chemicals are important for brain functioning, but they have different effects, depending on the region of the brain. Thus, in order to study them, it is not sufficient to only look at the chemical only, but one also has to consider where the chemical is acting.

The researchers studied animals (fruit flies and mice) and their emotions in the laboratory. For doing so, they turned specific neurons in these animals on and off in order to find cause-effect-relationships: which neural circuits in combination with which neurotransmitters are responsible for which outcome?

First, they conducted an experiment to find out whether fruit flies could really experience something like emotions. They found that this was the case by exposing the fruit flies to puffs of air and observing their reactions. Second, the researchers induced a state of arousal and excitement in fruit flies that had certain genes turned on or off and found that one group needed more time to calm down from the excitement than the other. Dopamine and its receptors were involved in this process, the neurotransmitter that is linked to attention, arousal, and reward, but also to drug abuse, Parkinson Disease and ADHD. In a follow up study, they looked at two aspects of ADHD, hyperactivity and learning disability, and found that both of these aspects were located in different areas of the flies’ brains. They came to the conclusion that the same receptor controls different functions in different areas of the brain.

Thus, Professor Anderson reasons, when treating psychiatric disorders, we need to treat specific regions of the brain rather than the brain as a whole.

What does this mean? First of all, further research is needed. The researchers are working with animal models at the moment. It is likely that their findings can be applied to humans, but so far, there is no evidence for this. Maybe one day, there will be medication for mental diseases that is specific enough to treat more or less only the symptoms of the illness without having too many side effects. In the meantime, we should be aware of the fact that drugs for mental diseases have many side effects and that we should abstain from taking them when they just a “quick fix”, while there is another (maybe more effortful) way of dealing with the disease that does not involve drugs. But above and before all, we should take good care of our mental health so that we don’t become mentally ill and need psychotropic drugs. What can we do for our mental health? We have a few findings here on the scienceblog, feel free to browse the posts. We also some exercises you can do, for example the Three Blessings or meditation.