Assuming that psychological disorders are the result of biological factors is not without its problems. For example, the classification of physical illnesses involves observation and measurement of objective symptoms such as broken bones, fever, blood pressure etc., whereas with mental illnesses, the symptoms are much more subjective — e.g., feelings of despair, lack of energy or hearing voices. These cannot be easily measured, so the clinician must make a judgement based largely on experience.
Also, the difference between physical and mental illness is that diagnosis of physical illness can normally relate to the causes of the problem (known as aetiology). For example, measuring blood sugar levels could check a diagnosis of diabetes. However as we will see, the causes of many mental illnesses are unknown. This has an important consequence for treatments based on the biomedical model, as they can be criticised as focusing only on the symptoms of mental disorders and not the causes.
Finally, humanistic and existentialist biased therapists after point out that the medical model in encouraging the view that people who suffer from mental disorders are ‘patients', hands responsibility over to doctors and other professionals. In this way the individual is discouraged from taking control of his or her own life and as a consequence his or her problems will ultimately remain unresolved. Against these negative criticisms could be set the undeniable progress that has been made in understanding the biological basis of many mental disorders (especially schizophrenia) and the successful development of bio-medical treatments. In summary, the strengths of the biological model are:
• The model is
