The debate over whether, and how, proneness to schizophrenia can be detected before a psychotic incident occurs has run for a number of decades. Theories of psychosis proneness, known as schizotypy, began to emerge in the 1950s. At this time the focus of attention was on people who were biologically related to a person diagnosed with schizophrenia, yet not themselves psychotic.
Today's classification system (DSM-IV-TR and ICD-10) refers to schizotypal personality disorder. In fact two categories of the disorder exist (schizoid and schizotypal) in order to make a distinction from schizophrenia and between the disorders. A common characteristic of both disorders is the lack of any overt psychotic symptoms. Behavior, in both cases, is often viewed as bizarre, odd or eccentric.
Schizoid Personality Disorder
Social withdrawal is the most obvious feature of schizoid personality disorder. This person tends to avoid close relationships, chooses solitary activities and is emotionally cold. There are no, or very few, symptoms of psychosis.
Schizotypal Personality Disorder
People with schizotypal personality reveal much more in the way of odd behavior. Their speech, thought processes and perceptions are all affected but not sufficiently to merit a diagnosis of schizophrenia. Schizotypal symptoms include rambling speech, hypersensitivity to criticism bordering on the paranoid and suspiciousness. Individuals sometimes report having the ability to read minds or predict the future, a feature known as magical thinking. Of these two personality disorder types, the schizotypal fits less easily into their surroundings and can, when under stress, exhibit brief psychotic symptoms.
Is a Category Diagnosis Outdated?
Reaching a diagnosis of personality disorder has always presented something of a problem. A personality disorder is considered to be stable over time, yet there is evidence (e.g. Loranger, Sartorius and Andreoli, 1994) to suggest that schizotypal personalities can be fairly unstable over quite short periods of time. Many of the earlier issues associated with refining a diagnosis of personality disorder have been resolved, but not entirely. It is no so long ago that 55 per cent of people diagnosed with a borderline personality disorder could just as easily have been diagnosed with schizotypal disorder (Widiger, Frances and Trull, 1987).
Schizotypy remains a diagnostic category of mental illness although some critics (e.g. Widiger and Costa, 1994) have argued that the experiences of such people do not differ sufficiently and distinctly from normal individuals to merit being described as mentally ill. An alternative perspective, they suggest, is to consider these behavioral characteristics as extreme personality characteristics. Of course our view of normality (and abnormality) changes frequently so there are obvious dangers of classifying behavior that might otherwise be considered eccentric or even creative or artistic.