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Is a Category Diagnosis Outdated?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.
There is now sufficient evidence to dismiss the notion that people simply have schizophrenia or they don't. In one example of research conducted by Chapman and Chapman (1985) people who scored high on psychosis-proneness scales were followed up 10 years later. Fourteen of the 182 people in the sample had progressed into a diagnosed state of psychosis, but the others had not. This, and other studies, point to the fact that measures for predicting psychosis do seem to work, and that not all people with psychosis-proneness become psychotic. In turn this brings us to a point where we can appreciate that schizophrenia itself may not inevitable - its onset perhaps more likely to be triggered by any one or more additional factors.
Chapman, L.J., & Chapman, J.P. (1985) Psychosis Proneness. In M.Alpert (Ed.), Controversies in schizophrenia. New York: Guildford Press.
Diagnostic and statistical manual of mental disorders. (DSM-IV-TR) 4th ed., text revision. Washington, DC : American Psychiatric Association, 2000.
International Statistical Classification of Diseases and Health Related Problems (The) ICD-10 Second Edition Vol 3, 2nd ed., World Health Organization, Geneva.
Loranger, A.W., Sartorius, N., Andreoli, A. et al. (1994) The International Personality Disorders Examination: the World Health Organisation/Alcohol, Drug Abuse and Mental Health Administration international study of personality disorders, Archives of General Psychiatry, 51: 215-23.
Widiger, T.A. & Costa, P.T. Jr (1994) Personality and Personality Disorders, Journal of Abnormal Psychology , 95: 43-51.
Widiger, T.A., Frances, A., and Trull, T.J. (1987) A psychometric analysis of the social-interpersonal and cognitive-perceptual items for the schizotypal personality disorder. Archives of General Psychiatry, 44: 786-95.
Jerry Kennard is a psychologist & co-founder of www.embarrassments.co.uk