title: Testing the Validity of Taxonic Schizotypy Using Genetic and Environmental Risk Variables.
abstract: Meehl regarded schizotypy as a categorial liability for schizophrenia that is the product of genes, environment, and gene-environment interactions. We sought to test whether schizophrenia-related genotypes and environmental risk factors predict membership in classes defined by taxometric analyses of positive (cognitive-perceptual), negative (interpersonal), and disorganized schizotypy.
  
  
  
  Participants (n = 500) completed the Schizotypal Personality Questionnaire (SPQ) and provided information on the following risk factors: cannabis use, pregnancy and obstetric complications, social adjustment, and family history of psychosis. Saliva samples were obtained so that the frequency of single-nucleotide polymorphism (SNP) alleles associated with risk for developing schizophrenia could be determined. Genotyped SNPs were rs1625579 (MIR137), rs7004633 (MMP16), rs7914558 (CNNM2), and rs12966547 (CCDC68). Sets of SPQ items were subject to multiple coherent cut kinetic (CCK) analyses, including mean-above-minus-below-a-cut, maximum covariance, maximum eigenvalue, and latent modes analyses.
  
  
  
  CCK analyses indicated latent taxonicity of schizotypy across the 3 item sets. The cognitive-perceptual class had a base rate of 25%, and membership was predicted by the rs7004633 SNP (odds ratio = 2.33, 95% confidence interval = 1.15-4.72 in adjusted analyses). Poor social adjustment predicted memberships in the interpersonal (16%) and disorganized (21%) classes. Classes were found not to be mutually exclusive.
  
  
  
  Schizotypy is taxonic and schizotypy class membership is predicted by genetic and environmental factors that predict schizophrenia. The findings hold the promise that a more complete understanding of schizotypy as a schizophrenia liability state will come from investigation of other genes and environmental factors associated with schizophrenia.
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Morton
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.
authors.forename: Kirstie J M
authors.initials: KJM
authors.lastname: O'Hare
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.
authors.forename: Jaimee L K
authors.initials: JLK
authors.lastname: Maha
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.
authors.forename: Max P
authors.initials: MP
authors.lastname: Nicolson
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.
authors.forename: Liana
authors.initials: L
authors.lastname: Machado
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand.
authors.forename: Ruth
authors.initials: R
authors.lastname: Topless
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand.
authors.forename: Tony R
authors.initials: TR
authors.lastname: Merriman
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand.|Department of Psychiatry and Psychology, Maastricht University, Maastricht, The Netherlands.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Linscott
mesh_terms: D000328:Adult; D027682:Cation Transport Proteins; D016213:Cyclins / Q000235:genetics; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D053513:Matrix Metalloproteinase 16 / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics; D012569:Schizotypal Personality Disorder / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics; D012917:Social Adjustment; D025521:Tumor Suppressor Proteins / Q000235:genetics; D055815:Young Adult
chemical_list: C000602811:CCDC68 protein, human; C558175:CNNM2 protein, human; D027682:Cation Transport Proteins; D016213:Cyclins; C545567:MIRN137 microRNA, human; C507102:MMP16 protein, human; D035683:MicroRNAs; D025521:Tumor Suppressor Proteins; D053513:Matrix Metalloproteinase 16
keywords: MMP16; class structure; maximum covariance analysis; psychosis; schizophrenia; social adjustment; taxometrics