How Is Mental Illness Diagnosed?

by Rethink

At the moment, there are no tests for mental illnesses. They cannot be diagnosed by checking the blood or body fluids of the person experiencing symptoms. There is hope that in the future scans of the brain, or some other test, will be used to confirm the presence of specific mental illnesses, but this is not yet possible. A diagnosis will usually be made by an experienced psychiatrist in working with other health professionals.

At first the person will be observed for symptoms, and the doctor will use pre-determined criteria to explore the person's behaviour, then the person will be observed over a period of time.

A full medical history should be taken and information about recent changes in the person's life should be obtained from family and/or friends. Usually one or more of these people will be involved in providing care for the relative with mental illness, and as a result will have an understanding of how the person's condition has developed.

The psychiatrist's ongoing assessment will follow one of the internationally agreed diagnostic schedules such as the International Classification of Diseases (ICD10) or the Diagnostic and Statistical Manual (DSM4).

It will be important for the psychiatrist to check that the symptoms are not part of some other medical syndrome, for example:

• high fever, epilepsy, problems with thyroid gland or diabetes,
• use of illicit drugs or alcohol,
• brain tumours, brain damage, following head injury or surgery,

This is because some symptoms found in mental illnesses, such as hallucinations, can also appear in other medical conditions. The psychiatrist should gather all observations together, eliminating any other possible cause.

Many different mental illnesses have overlapping symptoms and it can be difficult to tell the conditions apart. Reaching a diagnosis can be difficult and it takes time to be sure that the individual's symptoms truly indicate a particular mental illness. Family and friends can and should be involved, as they will be aware of details of family intimacies, cultural differences and religious beliefs. They may well be able to confirm to the professional that a desire for contact with a church, for example, is not a sudden change brought on by illness, but a part of the person's previous upbringing and normal practice.

Diagnostic Schedules, Why Do Doctors Sometimes Withhold The Diagnosis?

What do the diagnostic schedules do?

The diagnostic schedules set-out the criteria for each different diagnosis. For example, DSMIII states that a diagnosis of schizophrenia should only be made when the following criteria have been fulfilled:

• 1. Symptoms of the illness have been present for at least six months.
• 2. There has been some deterioration of functioning from previous levels in areas such as work skills, social relations and self-care.
• 3. The disease symptoms do not suggest organic mental disorders.
• 4. The disease symptoms do not suggest manic-depressive illness.
• 5. Either a, b or c must be present:
• a. Two of the following:
• i. delusions
• ii. hallucinations
• iii. disorganised speech (eg frequent loose associations or incoherence)
• iv. grossly disorganised or catatonic behaviour
• v. negative symptoms (eg emotional flattening, severe apathy), or
• b. Bizarre delusions which other people in the individual's subculture regard as totally implausible.
• c. Prominent auditory hallucination of voices keeping up a running commentary on the person's behaviour.

Why do doctors sometimes withhold the diagnosis?

Some psychiatrists and GP's do not like to give a diagnosis too early, or perhaps at all, especially when the person being treated is very young. This is because they are afraid of 'labelling' the person with a diagnosis which may affect his chances of obtaining employment, insurance or even housing in the future. Rethink is also aware of the profound effect which misunderstandings and prejudice about mental illness can have on someone with an illness, such as schizophrenia, and his carer. Doctors may be unable to make a quick diagnosis, since, for certain conditions, symptoms must be present over an extended period of time. For example, a diagnosis of schizophrenia means that symptoms must have been present for at least six months. On the other hand knowing the diagnosis can help both to find positive ways of coping, and sources of help like Rethink support groups. When the diagnosis is given both the person experiencing the symptoms and his carer may feel uncertain about it. If this worry persists, a second opinion can be requested. This might be arranged with another psychiatrist working locally or through the Second Opinion Clinic at the National Psychosis Unit in London which is part of the Maudsley and Bethlem Hospital Trust.

Future Aids to Diagnosis, Other Approaches to Diagnosis

brain scans

Neurological changes occur in the brains of people with most mental illnesses. Some of these can be seen using brain imaging techniques. It may be possible in the future to use brain imaging to make a diagnosis. However, this is not yet possible.

niacin flushing test

This is a test that is being developed for schizophrenia, it is still in the research stage and is not accepted as a standard test for schizophrenia.

The test works by measuring the level of particular fatty acids in the body. Since the polyunsaturated fatty acids that are supplemented when a person takes fish oil are found throughout the body, other cells apart from the nerves of the brain are affected by the reduced levels of fatty acids which some people with schizophrenia have.

One effect that the reduced levels of fatty acids has is in the way blood vessels can be made to dilate and the skin become flushed by the vitamin niacin. When a solution of niacin is painted on the skin the blood vessels will dilate and the skin will become flushed, but this will not happen in a person with reduced fatty acid. However, just as not all people with a diagnosis of schizophrenia have reduced levels of fatty acid, not all people will respond to the test.

Other Approaches to Diagnosis

While the above represents the dominant approach to understanding and diagnosis in Europe including Britain] and the Americas, there are dissenting voices within the world of psychiatry and critics outside on the concept of schizophrenia in particular and some critics would argue, that the accepted approach to diagnosis is flawed.

The dominant approach to mental disorder is based on a medical model of disease.

But some psychiatrists and mental health workers with a more family-oriented approach to treatment, while accepting the medical model for diagnosis in the first instance, will also rely more on the family to provide information about the history of the problems. Such workers tend to offer more support to families.

There is also some dissent in the western world of psychiatry over the extent to which environmental influences should be taken into account in assessing what is 'wrong' with someone presenting with psychiatric symptoms. the dangers of minority groups and especially ethnic minorities being mis-diagnosed and labelled is a common criticism. For more information about diagnosis and treatment for people from ethnic minorities see Rethink's information sheet on mental health and people from black and ethnic minorities.

Psychiatrists and healers from outside the West often have a different concept of the relationship of mind and body and of the place of the individual in his/her society. Their diagnostic procedures are less likely to follow western ideas of a medical /scientific approach and are less characterized by the mind/body split Some critics of western psychiatry point to the political an racist aspects of its history.

About the Author

www.rethink.org
Rethink is the largest severe mental illness charity in the UK. We are dedicated to improving the lives of everyone affected by severe mental illness, whether they have a condition themselves, care for others who do, or are professionals or volunteers working in the mental health field.