The theory behind Psychoticism: a reply to Eysenck

Abstract

In this reply to Eysenck, we attempt to clarify why we have criticized Eysenck's Psychoticism model and have found it necessary to introduce our own alternative model. It k concluded that the validity of the P scale as a measure of Psychoticism has not been demonstrated and that the P construct itsew is untenable.In 'How valid is the psychoticism scale? A comment on the Van Kampen critique ', Eysenck (1995) states that 'To summarize, Van Kampen (1993) has criticized the P scale, and suggested the validity of his S scale, with complete disregard for the universally recognized need for construct validity. His account of the P scale never mentions the large body of evidence supporting its construct validity, and his claim for the validity of his S scale simply refers to low correlations of his scale with other measures of similar concepts. Without evidence of construct validity, based on a properly formulated theory from which testable deductions can be made, personality traits and their corresponding questionnaire type measuring scales are merely correlational artifacts without a firm hold on reality' (p. 107).Of course, these statements of Eysenck seem to point to a very significant omission. For if the P scale is indeed a valid measure of the Psychoticism construct, there would have been no need to write such a critical article about Eysenck's P model, nor to replace the P scale with a scale for the measurement of S or Insensitivity. But in fact, things are not as simple as Eysenck suggests, and in our original publication many criticisms are levelled at P that Eysenck apparently passed over in silence. So, perhaps it makes sense to reiterate some of the main points addressed in our previous article to see why we have criticized Eysenck's P model and found it necessary to introduce the S scale.According to Eysenck (1992a), the theory of Psychoticism rests on two major presuppositions. 'The first is that all functional psychoses (schizophrenia, manicdepressive illness, schizoaffective disorders, monopolar depression) are related and do not form independent categories' (p. 670). Elsewhere, this presupposition is worded somewhat differently by stating that there exists 'some degree of generality

The DAPP-BQ in the Netherlands: Factor Structure and Relationship with Basic Personality Dimensions

“…In agreement with Eysenck's (1994) claim that a basic personality factor must form part of a general nomological network, but also criticizing his theory about P or Psychoticism (Van Kampen, 1996), we postulated four fundamental dimensions, namely S or Insensitivity, E or Extraversion, N or Neuroticism, and G or Orderliness, of which S and G took the place of Eysenck's P factor (Van Kampen, 1997). From a statistical point of view, much attention was paid on the invariance of the factors with respect to several sample parameters, including age and sex.…”

Cross‐sample and cross‐language invariance of the Five‐Dimensional Personality Test (5DPT): exploratory and confirmatory analyses using Dutch, American and Italian samples

“…Although we agree with Eysenck's (1994a) choice for the theory-based methodology as the most suitable one to answer the question which personality factors are basic (but see Van Kampen, 2009, for a slightly more balanced view, also addressing the lexical issue of comprehensiveness), the PEN theory itself can be criticized, particularly with respect to P. Elsewhere (see Van Kampen, 1993, 1996, 2009, we have described these criticisms in greater detail, but, essentially, it can be stated (1) that the genetic overlap of schizophrenia and manic depression as postulated by Eysenck appears to be nonexistent or at most limited to schizophrenia and unipolar depression;…”

“…Although we agree with Eysenck's () choice for the theory‐based methodology as the most suitable one to answer the question which personality factors are basic (but see Van Kampen, , for a slightly more balanced view, also addressing the lexical issue of comprehensiveness), the PEN theory itself can be criticized, particularly with respect to P. Elsewhere (see Van Kampen, , , , ), we have described these criticisms in greater detail, but, essentially, it can be stated (1) that the genetic overlap of schizophrenia and manic depression as postulated by Eysenck appears to be nonexistent or at most limited to schizophrenia and unipolar depression; (2) that, contrary to Eysenck's claim, only the schizoid (and not the ‘classical’) form of psychopathy belongs to the group of spectrum disorders genetically associated with schizophrenia; (3) that patients with schizophrenia, unipolar depression or manic disorder do not share the same premorbid personality traits believed by Eysenck to be associated with P; and (4) that in opposition to Eysenck's assertion, the testing of the P theory by means of proportionality analysis has not demonstrated the existence of a phenotypic continuum ranging from normality to psychosis because of the conflation of two conceptually different P models, the ‘phenotypic’ and the ‘genotypic’ model (see for the distinction Van Kampen, ).…”

“…As mentioned earlier, several papers bear on the construct validity of the 5DPT (Coolidge et al, ; De Vries & Van Kampen, ; Van Kampen, ,, ; Van Kampen et al, ). In addition, four papers have been published about the theoretical background of the 5DPT and its forerunners, the 3DPT and 4DPT (Van Kampen, , , , ). As such, much attention has been given to one of the objectives in Van Kampen's research, namely the establishment of a personality model of clinical interest that, while being constructed in the course of a critical revision of Eysenck's P theory, still adheres to Eysenck's methodological position regarding the role of theory and construct validity in personality science.…”

The 5-Dimensional Personality Test (5DPT): Relationships With Two Lexically Based Instruments and the Validation of the Absorption Scale

“…Elsewhere (see Van Kampen, 1993, 1996, 1997, we have described these deficiencies in greater detail, but, essentially, it can be stated that (a) the genetic overlap of schizophrenia and manic-depression as postulated by Eysenck appears to be nonexistent (Cardno, Rijsdijk, Sham, Murray, & McGuffin, 2002;Kendler & Gardner, 1997) or at most limited to schizophrenia and unipolar depression (e.g., Maier, Hallmayer, Minges, & Lichtermann, 1990); (b) contrary to Eysenck's claim, only the schizoid (and not the "classical") form of psychopathy belongs to the group of spectrum disorders genetically associated with schizophrenia (e.g., Heston, 1970); (c) patients with schizophrenia, unipolar depression, or manic disorder do not share the same premorbid personality traits believed by Eysenck to be associated with P (see, e.g., Bleuler, 1972;Lauer et al, 1997); and (d) in opposition to Eysenck's assertion, the testing of the P theory by means of proportionality analysis has not demonstrated the existence of a phenotypic continuum ranging from normality to psychosis because of the mixing up of two conceptually different P models, the phenotypic and the genotypic model (Van Kampen, 2009).…”