Do We Really Know What Causes Mental Illness?
What causes Schizophrenia?
The mystery of ‘cause’ is just as elusive in schizophrenia as in all mental illnesses. In fact, it is often the lack of a visible ‘cause’ that mystifies and infuriates people, both those who suffer from mental illnesses and those around them. It is the same reason that people often resort to supernatural explanations for mental illness often attributing it (especially in our primitive culture) to magic, the ‘evil eye’ or such.
Despite more than a century of research, modern science cannot shed much light on the cause of schizophrenia. Some associations have been found but they are far from explaining every case. For example, there appears to be a clear association between the development of schizophrenia like symptoms and the use of many street drugs like cocaine, stimulant drugs like methamphetamine or ‘Ice’ and others.
Surprisingly, one drug that is often thought to be safe because it is plant based and ‘natural’, namely Cannabis, has also found to be associated in many cases with the onset of schizophrenia. Cannabis, of course, is the active ingredient in substances derived from the plant ‘Cannabis Sativa’, the various parts of which are used to produce ‘charas’, ‘hash’ and ‘bhang’ in Pakistan (commonly known as ‘marijuana’ in the US).
Genetic factors have been proposed as a cause of the illness and certainly, like all illnesses (and in fact all aspects of our existence), schizophrenia too can be inherited, at least partially.
If you have one parent with schizophrenia, your chances of getting the illness are substantially higher than the general population. If both parents suffer from the illness then the chances of children getting schizophrenia increases manifold (although it’s unusual for people with schizophrenia to be able to marry and have children which may be an evolutionary adaptation).
Environmental factors have been identified to cause this illness, which include urban living, certain kinds of infections, poor nutrition during pregnancy and others, but the strength of evidence regarding all these factors remains low and they do not appear to explain the vast majority of cases. Unlike say, illnesses like malaria or dengue or typhoid fever, the ultimate cause of schizophrenia still eludes us, and thus, so does any effort at prevention.
How Can It Be Diagnosed?
Soon after I finished a lecture one morning, I got a call from a colleague about a student who appeared to be unwell. She was not doing well in her studies, failed a major exam and her progress was held back for a year. For the last several months, she often barged into a lecture and started haranguing the teacher. Other students complained that she often came up to them and started abusing them for no reason, and recently, she physically assaulted another student on campus. Campus security brought her to see me and it was clear that she was psychotic. She talked a lot but most of it was gibberish. She also got angry one minute and cried the next and appeared fearful and suspicious of both me and of her surroundings. Her friends reported that she had slept very little in the last few days, staying up all night on her computer and sometimes singing at all hours of the night.
Psychosis is fairly easy to spot since a person who is suffering from it is usually disruptive, aggressive and socially inappropriate. But psychosis is not a diagnosis. It is like fever, a non-specific symptom of an underlying illness and it can occur in many psychiatric illnesses: drug abuse, bipolar disorder, dementia and depression to name a few, can all indicate towards psychosis. In addition, many severe medical illnesses can also cause psychotic symptoms. Psychosis can occur in high fever, in brain infections like meningitis and many other medical illnesses.
The diagnosis of schizophrenia, like all psychiatric illnesses, requires that certain criteria be met before a person can be labeled with this illness. These include the presence of the most obvious symptoms of psychosis such as delusions and hallucinations along with disorganised behaviour or speech.
In addition, these symptoms must have been present continuously for at least a month or longer and cannot be due to drug abuse or a medical illness (even though psychosis due to drug or alcohol abuse or medical illness is treated the same way as schizophrenia).
The symptoms must also cause significant impairment in personal, social and occupational functioning i.e. these factors must make it difficult or impossible for a person to function at home, at school, with friends or at work.
Thus, it’s easy to see how an accurate diagnosis, especially early on in the illness can be hard since there can be so many confounding factors. I’m always reluctant to make a firm diagnosis of schizophrenia if there is the slightest chance that a person’s psychosis may be due to another cause since a diagnosis of schizophrenia invariably implies a downward course with usually, a poor response to medicines.
In any case, contrary to what most people think, psychiatric diagnoses are moving targets and I usually resist people’s demands to tell them a specific ‘diagnosis’. The reason is that unlike medical or surgical illnesses, most of which are rooted in specific areas of the body that we can pinpoint, the origins of psychiatric illness are still elusive. No one has yet managed to define the exact location or even assign a specific cause to most psychiatric illness, including schizophrenia.
We know that heavy drug or alcohol abuse or certain medical illnesses can cause symptoms of schizophrenia or depression or another psychiatric illness. There are many people who develop psychiatric illness even when they have never abused alcohol or drugs and are young and medically healthy. This leads to one of the most frustrating aspect of both living with and treating psychiatric illness because the cause is unknown. The truth is that we often simply don’t know.
Despite this, we have developed certain broad principles of diagnosing mental or psychiatric illness. This, of course, is a prerequisite to treatment. Our ‘diagnosis’ though, unlike the diagnosis of medical illness, does not involve looking for a bodily dysfunction. The ‘illness’ (or ‘disorder’ or whatever you want to call it) is in the mind (hence the term ‘mental’ illness) and the mind does not have a concrete physical existence (although we know that the mind is a function of a bodily organ: the brain). Therefore, instead of understanding the illness in terms of a bodily dysfunction, we group together common symptoms of a psychiatric illness and if enough symptoms co-exist together, we assign it a ‘diagnosis’ (while being quite clear that the ‘diagnosis’ is a total arbitrary construct).
Persons with schizophrenia for example suffer from delusions, hallucinations, disorganised behaviour and speech and need to have these symptoms for a specified period of time (usually more than a month) before psychiatrists consider a diagnosis of schizophrenia.
Similarly, people suffering from depression frequently have in common a constellation of symptoms, including depressed mood, low energy, crying spells, memory and concentration problems, sleep and appetite problems and sometimes thoughts of suicide for prolonged periods of time. And this holds true for all psychiatric symptoms.
While this may not be the most conventionally scientific method of diagnosis, given our lack of knowledge about the root cause of psychiatric illness, it gives us a starting point and, more importantly, can guide treatment. The fact that psychiatric illness cannot be located inside a specific bodily organ also means that conventional laboratory tests, X-rays, CT scans, MRIs etc are of no use in diagnosis or treating it. This is another perpetual source of frustration for our patients who often beseech us to order some test or the other that will give them a specific cause of their illness. Despite this lack of clarity in diagnosis, when it comes to treatment, we do have some options to offer.
(To Be Continued)
The writer is a psychiatrist practicing in Lahore. He taught and practiced Psychiatry in the United States for 16 years. He tweets @Ali_Madeeh