Schizophrenia has become a label for a severe mental illness often involving a loss of contact with reality. In addition, it is a highly complex disorder covering a wide variety of symptoms and types e.g. catatonic, paranoid and disorganised, meaning that classification and diagnosis is often difficult. Nevertheless, the risk is around 19%and there are no cultural or gender differences, although onset may occur later in females due to oestrogen which may slow down brain degeneration, nevertheless this hormone is said to decrease with age.
In terms of symptoms which are used in diagnosis and classification, there are the positive symptoms which reflect an excess or distortion of normal functions, - hallucinations, delusions, experiences of control and disorganised thinking. Furthermore, there are also negative symptoms which in fact reflect a loss or reduction in normal functions e.g. alogia (the loss of fluent speech) avolition (the loss of motivation) and accecore flattening (a reduction in the range of emotional intensity).
According to the DSM-IV-TR there are 5 distinct points which must be met for diagnosis to be made. Firstly, the patient must have been experiencing at least 2 symptoms for 1 month (N.B. if delusions bizarre one is enough), occupational/social dysfunction , continuous disturbance over 6 months with one month of symptoms, no other sign of mental illness and no other known organic cause e.g. drug abuse or brain tumour.
However, issues of classification and diagnosis involve looking at possible problems of reliability and validity.
In terms of the issues with reliability it is often found that inter-rater reliability is low, meaning that psychiatrists often have difficulty agreeing on diagnosis. Pre 1970’s a lot more people were diagnosed in the USA than in the UK, highlighting that classification may not be reliable. Nevertheless, improvements