Greg Detre���������������������������������������� Schizophrenia������� 10^th� February, 2000

Society�s views on �madness� have altered as psychopathology has replaced the devil as its cause. However, there is still some contention about whether there is something qualitatively different about cognitive dysfunction, marking it as a genuine pathology, or whether disorders are simply cases of marked anomalies with particularly intense symptoms relative to the majority of the population. Whether such illnesses are considered to be distinguishable abnormalities or deviances purely in terms of the degree of difference from the norm, psychopathologies cause considerable anguish and disability.

Schizophrenia is a term used to describe a group of serious disorders, affecting up to 1% of the population and accounting for about half the beds in mental health hospitals. Often mild symptoms remain undiagnosed until the twenties, but it can be a chronic condition that usually affects the young, if anything declining with age. Because of the difficulties of diagnosing a pathology which Bleuler characterised simply as an �abnormal disintegration of mental functions�, especially in its early stages, DSM-IV classifies schizophrenia being present in subjects displaying a number of pathologies in related areas persisting for 6 months.

Progress in its study has been slow, for a number of reasons. In the first place, the term �schizophrenia� is used to categorise an extremely wide range of disorders, including disorders of cognition, emotion, behaviour and social integration.

This led to Crow�s two-process theory, which divides it into two fairly distinct pathologies of varying severity, variously known as Type I and Type II, or positive and negative. The positive form is characterised by the presence of hallucinations, delusions and thought-disorders. The negative form displays as poverty of speech, flattening of affect and social withdrawal (especially noticeable biologically by the enlargement of the brain ventricles and shrinking brain mass).

More recent studies enlarge on this distinction, further dividing the �positive� category into �psychotic� and �disorganised�. This distinction can be partly justifed in physiological terms. It seems increasingly likely that schizophrenia cannot be seen in just psychological terms as a purely cognitive dysfunction; rather, evidence from treatment and autopsies suggests biochemical and anatomical anomalies which correlate reasonably well with a tri-partite distinction.

�Classical� anti-psychotic treatments like Thorazine and Haldol have proven reasonably effective in a large number of cases by blocking the dopamine receptors in the brain. There is a strong correlation between the effectiveness of a drug in forming dopamine blockades and its effect on positive schizophrenics. Increased circulation of dopamine in neural circuits appears to lead to schizophrenics� inability to concentrate on certain stimuli, being continually distracted by the extraneous and being unable to maintain a steady train of thought (just as patients suffering from a lack of dopamine sometimes exhibit opposite symptoms: ignoring stimuli and less active cognitive functioning). To see what happened, Davis injected a group of patients with mild schizophrenia with a drug with temporarily increases dopamine levels; it produced a startling increase in the floridity of the patients� symptoms, including catatonia, delusions and psychosis, further vindicating the dopamine hypothesis (Davis, 1974).� However, the most recent treatments are intended to affect more of the patients for whom simply dopamine-blockading, like Clozaril, is ineffective, by working on the dopamine and seratonin levels together, in recognition of an effect being caused by their interaction (Megens and Kennis, 1996).

As mentioned above, the dopamine hypothesis seems to apply more to patients suffering from the positive (Type II) forms of schizophrenia. In patients with the negative form, enlarged ventricles and shrunken brains are noticeable. Moreover, autopsies indicate further organic damage in the cerebellum and basal ganglia, but especially in the frontal and temporal lobes (Martin and Albers, 1995). There, cell derangement and missing or abnormally sized neurons must affect brain function, as backed up by fMRI and PET scans.

The ultimate cause is difficult to pin down, but there appears to be a genetic pre-disposition: there is an 8% chance that if one twin suffers from schizophrenia, the other will too at some point, a rate four times higher than for a random member of the population. The risk is also markedly increased by having one or both parents with the disorder. Studies to see whether the social environment somehow induced or increased the chances of the disorder suggested that the causal link worked the other way � if there were signs of a cold and dominating mother, for instance, this seemed to be more of a reaction to the difficulties of relating to her child, although when families who were helped to understand about the condition, sufferers released from hospital were less likely to have to return. Rather, obstetric reports and extraneous pre-natal conditions like influenza epidemics during the second trimester of pregnancy may play a role.

The effects of schizophrenia can be contrasted with those of Parkinson�s disease, which is often seen as the opposite side of the same coin, caused by a long-term decline in the presence of dopamine and the dopaminergic pathways, while the former seems to be linked with the dopamine receptors being over-stimulated. Yet, radically different effects are observed, and in different areas of the population. Parkinson�s disease tends to strike in the elderly (approximately 1% of the elderly population suffer from it), causing a marked decline in levels of dopamine, with worsening effect on the motor system, especially the basal ganglia.

Schizophrenia is a massively debilitating disorder � only 20% of schizophrenics interviewed thirty years after diagnosis appear to have been able to lead normal lives (Andreason & Black, 1996), while 45% were incapacitated. However, there are increasing grounds for optimism.