2.1 Diagnostic handbooks
Two handbooks or manuals are particularly significant in the process of psychiatric diagnosis; both are commonly known by their abbreviations: the DSM-V and the ICD-10. Both the books provide a comprehensive list of ‘mental disorders’ and are used by clinicians and researchers in the United Kingdom (UK) and many other countries.
- The DSM-5 (or DSM-V) is the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, produced by the American Psychiatric Association.
- The ICD-10 is the tenth edition of the handbook for International Classification of Diseases, produced by the World Health Organization (2004) and covers mental disorders in Chapter V. You will see how this handbook describes schizophrenia later in this course.
Both manuals take a fairly similar approach and describe many of the same conditions, mainly differing in how they group various disorders together in subsections of chapters. In both handbooks, sets of symptoms are listed (such as low mood, social withdrawal, problems sleeping and having auditory hallucinations) and, if enough of them can be attributed to the person presenting with problems, that person’s experiences are then assigned to a diagnostic category (for instance depression or schizophrenia).
Author and psychological therapist James Davies has interviewed some of the psychiatrists involved in drawing up the diagnostic categories for the Diagnostic and Statistical Manual of Mental Disorders and what he found was quite surprising. He first quotes Dr Robert Spitzer, who led the team developing the third edition of the manual:
There are very few disorders whose definition was a result of specific research data ... For borderline personality disorder there was some research that looked at different ways of defining the disorder. And we chose the definition that seemed most valid. But for the other categories rarely could you say that there was research literature supporting the definition’s validity.
If the definitions could not be determined by research evidence, Davies wondered how they were agreed upon. The answer was that the team were forced to rely on finding a consensus of opinion. Another team member, Professor Donald Klein, described how they came to a conclusion without the benefit of reliable data:
We thrashed it out basically. We had a three-hour argument. There would be about twelve people sitting down at the table, usually there was a chairperson and there was somebody taking notes. And at the end of the meeting there would be a distribution of events. And at the next meeting some would agree with the inclusion, and the others would continue arguing. If people were still divided, the matter would eventually be decided by a vote.
Although reaching a consensus or voting might appear to be a practical way forward in determining the classification of mental health problems, it is not scientific and is highly dependent on the opinions of the people in the room at the time. It would be surprising if conditions such as diabetes, asthma or stroke were decided in this way rather than being based on careful physical examination of the patient or by the results of post-mortem investigations. As you will find out in the later discussion of psychological approaches, the lack of physical evidence for the majority of mental health problems leads to problems of subjectivity and interpretation.