How is mental illness diagnosed?

At the moment, there are no ‘tests’ as such, for mental illnesses. Mental health problems cannot be diagnosed by checking the blood or body fluids of the person experiencing symptoms, as they are not looking for something which can be seen as present or not – which can be done for other conditions and illnesses such as diabetes or cancer.

A diagnosis will usually be made by an experienced psychiatrist working with other health professionals.

Initially, the person will be observed for symptoms, and the doctor will check through a ‘diagnostic schedule’ to find out how the person functions day to day. After this initial interview, the individual will be monitored 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 and the extent of the symptoms, and the impact it is having on quality of life.

It will be important for the psychiatrist to check that the symptoms are not part of some other medical syndrome, or other explainable cause (see physical causes of mental illness). 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, and then eliminate any other possible cause.

This process is not always easy, and it is not uncommon to have difficulties in either getting it recognised that you do have a mental illness, getting access to care and treatment, or that you may feel you have been given a misdiagnosis.

Many different mental illnesses have overlapping symptoms and so 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 routine.