The distribution of psychopathy among a household population: categorical or dimensional?
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The study aimed to examine the distribution of psychopathic traits in a representative household population to identify whether a transition point is reached on a continuum of psychopathy to indicate a ‘disease’ or categorical entity.
Mixture Poisson distribution and epidemiological procedures were used to examine the distribution of the Psychopathy Checklist Screening Version (PCL:SV) score in a sample of 638 adults in households in Great Britain. Analysis aimed to identify a cut-off within the population using the distribution of continuous scores (mean and ½ SD) and validate a ‘probable’ psychopathy category using a scale of social and behavioural problems as an external validator.
The distribution of psychopathy within the population was quasicontinuous, represented by a mixture of three-Poisson distributions with differing demography and comorbid Axis I and II psychopathology. Independent calculation indicated a cut-score at 11.8 on the PCL:SV. There was an exponential rise of associated social and behavioural problems at a transition point of 11.3. The prevalence of ‘probable’ psychopathy was 3.6% (95% CI = 2.3–5.5%) above this level.
The findings suggest a transition from a non-clinical to clinical state of psychopathy which can be defined categorically using a cut-off on the PCL:SV. The cut-off approximates to that previously recommended for identification of a case using the instrument. Above this critical level, individuals are at exceptional risk of compulsory care or incarceration due to multiple social and behavioural problems. Psychopathy should be considered for future inclusion in DSM-V and successfully combines both categorical and dimensional approaches to diagnosis.
Keywordsnational survey epidemiology probable psychopathy dimension or category
- 2.Babor TF, de la Fuente JR, Saunders J, Grant M (1992) AUDIT: the alcohol use disorders identification test: guidelines for use in primary healthcare. World Health Organisation, GenevaGoogle Scholar
- 3.Bebbington P, Nayani T (1994) The psychosis screening questionnaire. Int J Methods Psychiatr Res 5:11–19Google Scholar
- 4.Bolt D, Hare RD, Neumann CS (2007) Score metric equivalence of the PCL-R scores across North American and UK criminal offenders: a critique of Cook et al. (2005) and new analysis. Assessment 14(1):44–56Google Scholar
- 5.Chen F, Yang SQ (1997) Mixed Poisson distribution and it’s applications. Chin Health Stat 5:11–19Google Scholar
- 6.Cleckley H (1941) The mask of Sanity. Mosby, St LouisGoogle Scholar
- 7.Coid J, Yang M, Roberts A, Ullrich S, Moran P, Bebbington P et al. Prevalence and correlates of psychopathic traits in Great Britain. Int J Law Psychiatry (in press)Google Scholar
- 11.First MB, Gibbon M, Spitzer RL, William JBW, Benjamin L (1997) Structured clinical interviews for DSM-IV Axis-II personality disorders. American Psychiatric Press, WAGoogle Scholar
- 13.Hare RD (1991) The hare psychopathy checklist—revised. Multi-Health Systems, TorontoGoogle Scholar
- 14.Hare RD (2003) The psychopathy checklist—revised technical manual. 2nd edn. Multi-Health Systems, TorontoGoogle Scholar
- 16.Hart SD, Cox DN, Hare RD (1995) The hare psychopathy checklist: screening version. Multi-Health Systems Inc, New YorkGoogle Scholar
- 19.Kish L (1965) Survey sampling. Wiley, LondonGoogle Scholar
- 20.Lewis G, Pelosi AJ (1990) Manual of the revised clinical interview schedule (CIS-R). Institute of Psychiatry, LondonGoogle Scholar
- 23.Meehl PE, Golden R (1982) Taxometric methods. In: Kendall P, Butcher J (eds) Handbook of research methods in clinical psychology. Wiley, New York, pp 127–181Google Scholar
- 24.Meehl PE, Yonce LJ (1994) Taxometric analysis: I. Detecting taxonicity with two quantitative indicators using means above and below a sliding cut (MAMBAC procedure). Psychol Rep 74:1059–1274Google Scholar
- 25.Meehl PE, Yonce LJ (1996) Taxometric analysis: II. Detecting taxonicity using covariance of two quantitative indicators in successive intervals of a third indicator (MAXCOV procedure). Psychol Rep 78:1091–1227Google Scholar
- 26.van Os J, Verdoux H (2003) Diagnosis and classification of schizophrenia: Categories versus dimensions, distributions versus disease. In: Murray RM, Jones AB, Sussex E, van Os J, Cannon M (eds) The epidemiology of schizophrenia. Cambridge University Press, Cambridge, pp 364–410Google Scholar
- 27.Singleton N, Bumpstead R, O’Brien M, Lee A, Meltzer H (2001) Psychiatric morbidity among adults living in private households, 2000. The Stationery Office, LondonGoogle Scholar
- 32.Tanner JM (1989) Foetus into man. Castlemead Publications, WareGoogle Scholar
- 33.WHO (1999) SCAN schedules for clinical assessment in neuropsychiatry, Version 2.1. In: Health DoM (ed) World Health Organisation, GenevaGoogle Scholar
- 34.Waller NG, Meehl PE (1998) Multivariate taxometric procedures: distinguishing types from continua. Sage, Newbury ParkGoogle Scholar
- 35.Wing JK, Babor TF, Brugha T, Burke J, Cooper JE, Giel R et al (1990) SCAN: schedules for clinical assessment in neuropsychiatry. Arch Gen Psychiatry 47(6):586–593Google Scholar
- 36.Yang M (1983) A method of dissecting mixed samples for estimating the normal values of medicine. Chin J Prev Med 17:275Google Scholar