Studies carried
out with standardized clinical interviews had revealed that those experiences
and beliefs that can be ascribed to the psychotic dimension are quite common in
non-clinical populations.
A recent study
carried out in Italy by Dr Antonio Preti in collaboration with Dr Carmelo
Masala and Donatella R. Petretto of the Department of Psychology, University of
Cagliari, Italy, found that delusion-like
beliefs are endorsed by at least 25-30% of the people, and those with the most
clearly psychopathological connotation are endorsed by
about 10-15% of participants.
Hallucinatory experiences, on the other hand, are endorsed by
5-10% of the people, with around 0.4-0.8% endorsing the items with the most
clearly psychopathological connotation.
Both
delusion-like beliefs and hallucinatory experiences are related to a higher
chance of psychological distress. However, results indicate that hallucination
proneness and psychosis proneness do not overlap in the non-clinical
population, but can both cause distress separately.
Screening
instruments aimed at investigating indexes of risk within the psychosis
spectrum could be particularly valuable when used as a quantitative phenotype
in linkage and association studies on mental disorders with psychotic features,
such as schizophrenia and bipolar disorders.
However,
implications for use in the early detection of psychosis require further
exploration.
Reference:
Preti A,
Bonventre E, Ledda V, Petretto DR, Masala C
Hallucinatory
experiences, delusional thought proneness and psychological distress in a
nonclinical population.
Journal of
Nervous & Mental Disease, 2007; 195: 484-491.
Contacts:
Dr Antonio
Preti
SchizophreniaProject
e-mail: apreti@tin.it