Delusions in the nonclinical population.
ABSTRACT Delusions have long been considered a hallmark of psychotic disorders such as schizophrenia. However, delusions may only be most visibly present in psychotic conditions and could also occur in nonclinical groups. The aim of this review is to establish whether delusions, as traditionally considered and assessed in psychiatric conditions, are also present in individuals without a psychiatric or neurologic condition. Clear evidence is found that the rate of delusional beliefs in the general population is higher than the rate of psychotic disorders and that delusions occur in individuals without psychosis. The frequency of delusional beliefs in nonclinical populations varies according to the content of the delusion studied and the characteristics of the sample population. Approximately 1% to 3% of the nonclinical population have delusions of a level of severity comparable to clinical cases of psychosis. A further 5% to 6% of the nonclinical population have a delusion but not of such severity. Although less severe, these beliefs are associated with a range of social and emotional difficulties. A further 10% to 15% of the nonclinical population have fairly regular delusional ideation. There is convincing evidence that delusional ideation, delusions, and clinically severe delusions are related experiences. Information about clinical delusions can therefore be obtained by studying delusional ideation in nonclinical populations.
- SourceAvailable from: María Xesús Froján Parga[Show abstract] [Hide abstract]
ABSTRACT: The functional analysis of verbal behavior has been successful in establishing basic and advanced forms of language in individuals with developmental disabilities. The development of behavioral approaches to psychotherapy, such as the functional-analytic psychotherapy, have advanced the implementation of operant analyses of verbal behavior among typical adults. The field of behavior-analytic approaches to psychotherapy departs from the applied experimental research in behavior analysis in various ways: (a) minimal use of molecular analyses of behavioral processes using single-subject experimentation, (b) confined use of functional analysis and function-driven intervention, and (c) metaphoric use of mainstream behavioral concepts and methods. The breakthroughs brought about by behavioral approaches to psychotherapy may be supplemented by way of translating some of the findings of the applied experimental literature. The present analysis illustrates how behavioral processes demonstrated in the context of experimental research, often with individuals with developmental and intellectual disabilities, may be relevant to psychotherapy with typically-developed adults. This translational approach is discussed with reference to basic language processes: echoics, mands, tacts, and intraverbal dynamics. This approach could prompt programmatic translational research in the field of behavioral psychotherapies.International Journal of Clinical and Health Psychology 11/2014; · 2.79 Impact Factor
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ABSTRACT: Background: Patients with schizophrenia show overconfidence in memory and social cognition errors. The present investigation examined whether this cognitive distortion also manifests in perceptual tasks. Methods: A total of 55 individuals with schizophrenia, 58 with obsessive–compulsive disorder (OCD) as well as 45 non-clinical controls were presented 24 blurry black and white pictures, half of which contained a hidden object; the other half contained (" snowy ") visual noise. Participants had to judge whether the pictures depicted an object or not and how confident they were in this judgment. Results: Participants with schizophrenia showed overconfidence in errors and an enhanced knowledge corruption index (i.e. rate of high-confident errors on all high-confident responses) relative to both control groups. In contrast, accuracy scores did not differ between clinical groups. Metacognitive parameters were correlated with self-rated levels of current paranoia. Discussion: To the best of our knowledge, this is the first study to demonstrate overconfidence in errors among individuals with psychosis using a visual perception task. Speaking to the specificity of this abnormality for schizophrenia and its pathogenetic relevance, overconfidence in errors and knowledge corruption were elevated in patients with schizophrenia relative to both control groups and were correlated with paranoia.Schizophrenia Research: Cognition. 01/2014; 1:165-170.
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ABSTRACT: Background and Objectives: Overconfidence in errors is a well-replicated cognitive bias in psychosis. However, prior studies have sometimes failed to find difference between patients and controls for more difficult tasks. We pursued the hypothesis that overconfidence in errors is exaggerated in participants with a liability for psychosis relative to controls only when they feel competent in the respective topic and/or deem the question easy. Whereas subjective competence likely enhances confidence also in those with low psychosis liability, we still expected to find more 'residual' caution in these subjects. Methods: We adopted a psychometric high-risk approach to circumvent the confounding influence of treatment. A total of 2,321 individuals from the general population were administered a task modeled after the "Who wants to be a millionaire" quiz. Participants were requested to endorse one out of four response options, graded for confidence, and asked to provide ratings regarding subjective competence for the knowledge domain as well as the subjective difficulty of each item. Results: In line with our assumption, overconfidence in errors was increased overall in participants scoring high on the Paranoia Checklist core paranoia subscale (2 SD above the mean). This pattern of results was particularly prominent for items, in which participants considered themselves competent and which they rated as easy. Limitations: Results need to be replicated in a clinical sample.Discussion: In support of our hypothesis, subjective competence and task difficulty moderate overconfidence in errors in psychosis. Trainings that teach patients the fallibility of human cognition may help reduce delusional ideation.Journal of Behavior Therapy and Experimental Psychiatry 12/2015; · 2.23 Impact Factor