Diagnosis

• Schizophrenia or bipolar disorder?
• Making a diagnosis
• Classification systems
• Is diagnosis a label?

Schizophrenia or bipolar disorder?

There is ongoing controversy about diagnoses of mental illness which involve psychotic symptoms. People with schizophrenia can also become depressed, miserable or manic, and people with bipolar disorder may hear voices or have delusions.

Because there is overlap between the symptoms of schizophrenia and bipolar disorder, diagnosis is often not clear-cut. Diagnosis is usually made according to the combination of symptoms an individual has during their most recent acute episode, so it may change over the years.

So, for example, it is not unusual for someone to be given a diagnosis of schizophrenia, then a diagnosis of bipolar disorder, then a diagnosis of schizophrenia again, then a diagnosis of schizoaffective disorder. These different diagnoses would be given in response to the symptoms they had when they were most recently assessed by a health professional.

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Making a diagnosis

There are no blood tests or other physical checks for mental illnesses involving psychosis. A doctor may run physical tests, however, to rule out other medical conditions, particularly those that may cause mood problems.

Health professionals make a diagnosis of serious mental illness by carrying out a psychiatric interview. They will check how people look and behave, listen to the way they speak and what they say, watch how they move, and ask them questions about themselves – their mood, what they are thinking, for example. They will ask about people’s families and whether there is a history of mental ill health, and also ask how long people have been feeling this way. Health professionals should also speak to family members and ask what they have noticed about someone’s behaviour.

Brain scans should not be used to help make a diagnosis after a first episode of psychosis. Guidance from the National Institute for Health and Clinical Excellence says using scans after a first episode does not improve diagnosis and is not cost effective. Scans may be used, however, if doctors think the symptoms of psychosis are being caused by a physical health problem.

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Classification systems

There are two ‘frameworks’ used by health professionals to make diagnoses of mental health problems.

The first is called the Diagnostic and Statistical Manual of Mental Disorder (DSM), which is published by the American Psychiatric Association (APA). The APA is the main professional organisation of psychiatrists in the USA. The DSM was first published in 1952 and there have been four revisions since then. The APA is currently updating DSM. The Manual in current usage is called DSM-IV (because it is the fourth revision) and DSM-V, the new update, is due for publication in 2012.

The second is called the International Classification of Diseases (ICD), which includes a special section on psychiatric illnesses. The current document is called ICD-10 because it is the 10^th revision. ICD is published by the World Health Organisation and it is currently working on an updated version that is due to be complete by 2015. The updating of the guides involves reviewing scientific knowledge and evidence from recent research.

The existing DSM-IV and ICD-10 vary slightly in their definitions of schizophrenia and bipolar disorder. Both agree on the cluster of symptoms that lead to a diagnosis of schizophrenia, for example, but ICD-10 says that symptoms should be present for one month while DSM-IV says there should be evidence of ongoing symptoms for at least six months before a diagnosis is made.

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Is diagnosis a label?

Sometimes people are relieved to get a diagnosis, but other people fear being given a ‘label’ that will determine how they are treated. Some people feel a diagnosis is a negative thing, because of the stigma attached to mental health problems. For others, a diagnosis leads to treatment – sometimes compulsory – that they might not want.