A while ago, I saw an Indian movie in which the female protagonist was afflicted with visual and auditory hallucinations, bizarre paranoia and delusions. Of course, there was a song and dance sequence to accompany it. This movie spurred me to go online and look for more information regarding this ‘madness’. I learnt about Schizophrenia and later about Autism spectrum disorder. There is a TED talk by Jill Bolt Taylor who talked about the most fascinating things in a very interesting manner. You can find that here.
Ever since, I have made an effort to know more about this interesting disorder and today, I wish to introduce this topic to you. Before we do, I believe it is important to understand the structure of the brain. You can find some information here which has a fun, interactive way of learning about the basics of brain and its function.
It is important to know that Disassociative identity disorder (Usually referred to as split personality or multiple personality disorder) is different from Schizophrenia. People afflicted with this disorder, as described above, suffer from hallucinations, delusions, behavioural problems etc. which makes it difficult for them to be accepted in the society.
Most medications prescribed for patients with this disorder belongs to the class of molecules which have a capacity to suppress the activity of dopamine (sometimes serotonin as well) receptors. Clinical studies relating schizophrenia to brain dopamine metabolism have ranged from controversial to negative, with HVA levels in the CSF the same for schizophrenics and controls. There is a dopamine hypothesis theory on the internet, have a look.
Dopamine receptors (D1-D5) are G-protein coupled receptors meaning they work through secondary messenger system (like Adrenalin). Serotonin receptor aka 5-HT receptors are ion gated channels. I remember writing a post about ion channels. Check it out!
Let us see where dopamine is present in high quantity and what it does to the system. The ventral tegmental area (VTA, situated in mid brain) contains the largest group of dopamine neurons in the human brain. The main function of dopamine is to set a threshold for executing behaviors. Meaning, if a certain high level of dopamine activity occurs, a lower impetus is enough to evoke a given behavior. As a consequence, high levels of dopamine lead to high levels of motor activity and “impulsive” behavior; conversely, low levels of dopamine lead to torpor and slowed reactions. Another function of dopamine is to ‘teach’. If an action is followed by an acitivty, it alters the brain in such a way that same action becomes easier to execute if performed at a later time. There are several theories surrounding how this occurs. Most of them involve basal ganglia modifications.
In my next post, I shall talk about the controversy surrounding usage of anti – psychotic drugs for treatment of Schizophrenia.