Psychotic symptoms in the general population - An evolutionary perspective

The British journal of psychiatry: the journal of mental science (Impact Factor: 7.99). 09/2010; 197(3):167-9. DOI: 10.1192/bjp.bp.109.076018
Source: PubMed


Our ideas about the intrinsically pathological nature of hallucinations and delusions are being challenged by findings from epidemiology, neuroimaging and clinical research. Population-based studies using both self-report and interview surveys show that the prevalence of psychotic symptoms is far greater than had been previously considered, prompting us to re-evaluate these psychotic symptoms and their meaning in an evolutionary context. This non-clinical phenotype may hold the key to understanding the persistence of psychosis in the population. From a neuroscientific point of view, detailed investigation of the non-clinical psychosis phenotype should provide novel leads for research into the aetiology, nosology and treatment of psychosis.

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Available from: Ian Kelleher, Apr 11, 2014
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    • "Demographic and clinical correlates of pre-psychotic prodromal symptoms in the general population include substance use, stressful life events, and experiences of victimisation, lower intellectual ability and neurotic symptoms (Johns et al., 2004). These are similar to the risk factors identified for people with clinical psychosis, thus strengthening the perception of psychosis as a neurodevelopmental phenomenon and fuelling speculation of an evolutionary basis for psychosis (Kelleher et al., 2010). With specific reference to childhood trauma, Kelleher et al. (2008, 2013) have reported a link with future psychopathology. "
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    ABSTRACT: Objective: This study aimed to investigate the relationship between prodromal psychotic symptoms and psychological distress among Nigerian adolescents.Method: Students (n=508) were randomly selected from secondary schools in Abeokuta, Nigeria. A socio-demographic questionnaire, the Prodromal Questionnaire-Brief Version (PQ-B) and the Strengths and Difficulties Questionnaire (SDQ) were administered to each student.Results: The mean age of the students was 15.4 years (SD 1.3), with most (63%) being female. More than half (55.3%) reported having had a lifetime experience of major life event (20.9% in the preceding 6 months) while 13.9% had experienced bullying or abuse (5.1% in the preceding 6 months). The prevalence of prodromal symptoms was 20.9% (95% CI 0.174–0.244). Abnormal scores in emotional and conduct problems were seen in 11.8% and 6% respectively, while 7.3% had abnormal scores in each of the hyperactivity and peer problems subscales of the SDQ. Abnormality in prosocial behaviour was found in 1.8% of students, with overall abnormality in 4.9%. Regression analysis showed that prodromal symptoms were predicted by female sex, lifetime and 6 month history of major life event, and lifetime and 6 month history of bullying or abuse. Prodromal symptoms were also predicted by higher total SDQ scores and higher scores in all domains of psychological distress except the prosocial domain. Conclusion: The study showed a relationship between reported prodromal symptoms and the occurrence of psychological distress. It also showed that early childhood trauma may be a predisposing factor to the early stages of development of psychosis, with female children being especially prone in the years of adolescence.
    Full-text · Article · Dec 2015 · Journal of Child and Adolescent Mental Health
    • "Schizophrenia may be considered a human-specific disorder arisen as a maladaptive by-product of human-specific brain evolution (Crow, 1997; Crespi et al., 2007; Kelleher et al., 2010). Therefore, assuming schizophrenia as a neurodevelopmental disorder (Rapoport et al., 2012), new schizophrenia susceptibility variants may be detected by the analysis of neurodevelopmental genes related to human-specific traits. "
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    ABSTRACT: Schizophrenia may be considered a human-specific disorder arisen as a maladaptive by-product of human-specific brain evolution. Therefore, genetic variants involved in susceptibility to schizophrenia may be identified among those genes related to acquisition of human-specific traits. NPAS3, a transcription factor involved in central nervous system development and neurogenesis, seems to be implicated in the evolution of human brain, as it is the human gene with most human-specific accelerated elements (HAEs), i.e., .mammalian conserved regulatory sequences with accelerated evolution in the lineage leading to humans after human-chimpanzee split. We hypothesize that any nucleotide variant at the NPAS3 HAEs may lead to altered susceptibility to schizophrenia. Twenty-one variants at these HAEs detected by the 1000 genomes Project, as well as five additional variants taken from psychiatric genome-wide association studies, were genotyped in 538 schizophrenic patients and 539 controls from Galicia. Analyses at the haplotype level or based on the cumulative role of the variants assuming different susceptibility models did not find any significant association in spite of enough power under several plausible scenarios regarding direction of effect and the specific role of rare and common variants. These results suggest that, contrary to our hypothesis, the special evolution of the NPAS3 HAEs in Homo relaxed the strong constraint on sequence that characterized these regions during mammalian evolution, allowing some sequence changes without any effect on schizophrenia risk. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    No preview · Article · May 2015 · American Journal of Medical Genetics Part B Neuropsychiatric Genetics
    • "Evolutionary theorists have been particularly struck by a central question of schizophrenia: if this highly heritable condition confers such negative effects on fitness, why has it not been selected out (Kellenher et al., 2010)? This has led some to formulate psychosis as one end of the spectrum of a fundamental genetic variation common to Homo sapiens (Burns, 2004; Crow, 1997; Kellenher et al., 2010). For example, Crow (1997) has argued that it developed as part of the brain changes associated with the evolution of language, especially its lateralisation. "
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    ABSTRACT: Auditory hallucinations are experienced by more than two-thirds of those who receive a diagnosis of schizophrenia. One of the most established ways of seeking to promote acceptance of voices through therapeutic interventions has been to attempt to cultivate 'insight'. This form of acceptance has been central to some forms of cognitive behaviour therapy (CBT) for psychosis. Acceptance and commitment therapy (ACT) for psychosis and other mindfulness-based interventions are at an early stage of development and evaluation in terms of both outcome and process, and as such it cannot be regarded as an evidence-based treatment for either auditory hallucinations or psychosis. Nevertheless, a number of potential synergies exist between ACT and other theoretical frameworks.
    No preview · Chapter · Mar 2013
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