"Imagine if you'd suddenly learnt that the people, the places, the moments most important to you were not gone, not dead, but worse- had never been. What kind of hell would that be?". - A Beautiful Mind, 2001.
I saw the movie for the second time last night and it got me thinking about the complex disorder that is schizophrenia, and the intense effects it has on an individual, making him lose the distinction between real and imaginary. So what is it that makes a person harbour irrational thoughts and so convinced about the his false fears? I tried to poke around the literature to try to understand how much of the organic basis for this disorder is understood. There is the genetic component- the heritable nature of this disorder has been well documented over the years. Mutations in genes that are involved in brain function can be inherited, causing offspring of schizophrenics to be that much more at risk of developing the disorder. The environment plays an equal role, stress and psychological trauma are known to have a causal or triggering effect in schizophrenia, translating genetic predisposition to development of the disorder.
The neuropathology of the disease itself is closely linked to the above described factors. Bad genes, as well as early trauma to the brain, prenatal exposure to infections and psychological trauma result in brain abnormalities that cause cognitive defects and result in the disorder. There are two aspects to understanding how impaired brain function leads to this condition. Firstly the anatomic location of neural systems that are disrupted govern the types of symptoms exhibited by a patient. Various regions of the brain are involved in different functions such as processing impulses, perceiving thoughts and producing a reaction to a stimulus. The distortion in reality observed in schizophrenics is attributed to one region of the brain, thought disorganisation involves malfunction of a different circuit, while a decline in perceptive and physical responses are traced to malfunction in yet another circuit.
Secondly, brain chemistry- in terms of fluctuations in neurotransmitters (the chemicals that transmit signals in the brain cells) control the duration of above mentioned symptoms, to add another layer of complexity to this intricate orchestration. The sum effect of all of this is disorganised thinking, delusional and paranoid thought processes and auditory hallucinations that manifest as schizophrenia.
Dopamine, glutamate and NMDA are some of the neurotransmitters that have been implicated in schizophrenia. The "Dopamine hypothesis" is particularly famous, as it was one of the first major biological causes that could be attributed to schizophrenia. However, it is now thought to be an oversimplification at understanding the disorder, since there are other factors that play a role. Nevertheless, I will discuss the hypothesis because it provides atleast some insight into the process, and is quite fascinating.
Dopamine is a neurotransmitter, and in one of it's functions it is associated with the "pleasure system" of the brain, providing feelings of enjoyment and motivating a person proactively to perform certain activities. Essentially, it mediates the conversion of an outside stimulus from being a "cold" or neutral bit of sensory information into an "attractive" or an "aversive" entity.
For example- normally an external stimulus such as a bright red sports car zipping past a pedestrian might result in a surge of dopamine to cause an appropriate reaction- like the pedestrian turning his head to look at the car. However, the reaction elicited also depends upon the the pedestrian's predispositions and experiences. A race-car enthusiast may turn to look, while a person not interested in sports cars will not exhibit any reaction. In any case, dopamine here mediates a contextually relevant reaction.
In the 1970s, it was discovered that drugs that block dopamine function reduced psychotic symptoms. Further studies led to the hypotheses that dysregulated dopamine transmission causes an abnormal release of dopamine, so that what would have been a normally neutral stimulus results in firing up of neurones and causes aberrant reactions to external objects or their internal representations. Remember Nash in the movie reacting to something as simple as his wife turning on the light by saying "Why did you turn on the lights? Why would you do that? Why?" ?
In this stage, the patient develops a sense of anxiety and confusion, and an intense need to make sense of the new "realities" being experienced. Any and every normal occurrence can produce an exaggerated response in his mind, and he keeps looking for meanings and explanations to calm himself down. As he forms delusions in his mind to explain the occurrences, he experiences a feeling of relief and reduced perplexity. These delusions then persist, even after the stimulus is taken away, eventually taking on a life of their own. Hallucinations arise from similar aberrant thought processes, as the patient conceives an incorrect internal image of a thought or a memory that is percieved and reinforced with such intensity as though it were real.
This is, like I said earlier, just one aspect of cause and development of psychoses but enough to give us a peek into the on-goings in the brain of a schizophrenic. Imbalances in other neurotransmitters and pathways have different ways of interfering with normal thought process and causing psychological disturbances. Given the limited knowledge and understanding of this disorder, how is it brought under control?
Anti-psychotics are useful in the treatment of psychoses, because, in one way, they dampen the effect of the excessive dopamine (in this example) and thus restore a chemical balance that calms the patient. However, they do not change the underlying thought process- all they can do is prevent neutral stimuli from producing abnormal reactions, and quenching aberrant reactions produced initially. Thus, patients are able to "ignore" or control their reactions to stimuli, but are not entirely free of the delusional thoughts that have already formed. This underscores the importance of staying on the drugs as long as is necessary, and also protecting the patient from high stress environments that can cause a resurgence of symptoms. Modern drugs are now being developed to limit side-effects in patients. Imaging technologies have improved to better visualise brain abnormalities associated with schizophrenia. With the availability of genome sequences and better tools, more genes are being discovered that may play a role in the disorder. Emerging tools in pharmacogenomics can make the best of these discoveries to improve treatment. Social acceptance and sensitivity towards the ailment is also needed , to create a support system that does not stigmatise patients.
John Nash's story is a very encouraging one in the face of this complex disorder. His story shows that one can be successful in bringing the disorder under control to a large extent. Eventually, Nash learns to ignore his irrational fears and focus on his passion. The same brain that gave rise to abnormal thought processes also contributed to his Nobel-prize-winning work on the game theory. Indeed, the mind is a beautiful thing!
References: 1) Wikipedia
2) Schizophrenia: challenging the orthodox McDonald et al
3) Schizophrenia in a molecular age. Carol A Tamminga