The following symptoms are listed as classical signs for the diagnosis of schizophrenia.

• Once called dementia praecox (early senility), the onset of the disorder occurs before the age of 45

• Lasts for more than six months

• Inability to test reality

• Type I: disturbances of thought such as delusions, hallucinations and bizarre thoughts. Often complaining of being controlled by others such as aliens and of hearing voices (auditory hallucination).

• Type II: withdrawal, blunted feelings (affect) and reduced motivation. This has a much poorer prognosis than type I. Both types may occur in one patient.

Genetic evidence

Kendler (1983) found a correlation in dizygotic twins of around 15%, but that this rises to 50% for monozygotic twins, supporting his argument for a strong genetic component

Adoption studies

Wendell et al. (1974) found those children born to a schizophrenic parent and then adopted was more likely to become schizophrenic than a child from normal parents.

Heston (1996) found that adopted children whose natural mothers were schizophrenic were five times more likely to be diagnosed schizophrenic.

Viral

Crow (1984) proposes that schizophrenia could be caused by a retrovirus which becomes incorporated into the DNA and thus causing schizophrenia to be passed on. This is supported by the fact that schizophrenia can occur in families where it has never occurred before.

Chromosome evidence

Evidence has been found for a chromosomal abnormality by Sherrington et al. (1988). A cluster of genes on chromosome 5 seems to make the individual susceptible. This work has not yet been confirmed.

Neurochemical

• An excess of dopamine activity has been demonstrated as being related to type I schizophrenic symptoms. Neuroleptics are drugs designed to block the sites involved in the release or transmission of dopamine. These are used to alleviate schizophrenic symptoms.

• Large amounts of drugs such as amphetamines, cocaine, LSD and the drug used to treat Parkinson’s disease (L-Dopa) can all cause behaviours which resemble the psychotic states of schizophrenia. All of the above mentioned drugs stimulate the release of dopamine (apart from L-Dopa, which simulates dopamine)

• When the brains of people suffering from schizophrenia are examined on post-mortem, they are found to contain high levels of dopamine.

Neuroanatomy

Some studies have shown that type II symptoms are related more to brain structure than dopamine levels. Post-mortem study of the brains of type II schizophrenics show that they exhibit less neurons in the cerebral cortex and that the brains weigh 6% less than other brains.

PET and CAT scans also show that schizophrenics have larger ventricles, which means that more space in the brain is occupied by fluid than by neurons

Known Organic Disorders

Organic disorders such as brain tumours can lead to psychotic states similar to those of schizophrenia.

Learned response

Bateson et al. (1956) argued that schizophrenia is a response to mutually exclusive demands made upon a child. This is called the double-bind theory. These demands cannot be avoided, nor can they be satisfied and therefore schizophrenia is a learned response to impossible demands. Laing (1959) argued that schizophrenia is a sane response to a distorted environment. He further argues that the self becomes divided between the person’s internal and external world and that schizophrenia is not an illness, but a response to the world that is aggravated by ‘pathological’ families.

Triggers

Stress may be a trigger (although Rabkin (1980) found that schizophrenics did not report any more stressful events prior to the onset of an episode. Faulty communication within pathological families is seen as a trigger (see above).

Social drift

Schizophrenia tends to affect the poor rather than the rich. Two factors may account for this: That the person falls lower in the socio-economic status because of the illness; or that the socio-economic disadvantages themselves cause the illness. Turner and Wagenfeld (1967) surveyed the population of New York and found that there was a relationship between social class and schizophrenia. They found evidence for both socio-economic drift and social causation.

• Drugs, such as neuroleptics
• Psychotherapy may also help sufferers develop an insight into their illness after the main symptoms have been alleviated through drugs
• Family therapy is suggested for the dysfunctional family
• Therapeutic communities help the sufferer to live in positive social environment
• Outpatient treatment is being increasingly used to ensure that patients are taking medication instead of hospitalization. Linked to this is the assigning of a community psychiatric nurse.