[The concept of schizoidia in psychiatry : From schizoidia to schizotypy and cluster A personality disorders]. / Das Schizoidie-Konzept in der Psychiatrie : Von der Schizoidie über die Schizotypie zu den Cluster­A­Persönlichkeitsstörungen.

From a perspective of conceptual evolution schizoidia was initially considered to describe features both of the premorbid personality of schizophrenic patients and of the personalities of non-psychotic family members (Bleuler, Kahlbaum, Kraepelin). On a psychopatholocial level a close link to the complex basic symptom of autism was stressed. From the very beginnings of modern psychiatry schizoidia was discussed within a conceptual frame of schizophrenia spectrum disorders (Kretschmer, Hoch, Polatin). Approaches to operationalize these conceptual works laid the basis for the cluster A personalities in DSM-III. Due to the prominent concept of schizotypy (Kety, Rado, Meehl) three split up diagnostic categories of schizotypal, schizoid and paranoid personality disorders resulted. Cluster A personality disorders are frequent in community-based epidemiological studies. Health-care seeking behaviour due to primary personality-related problems, however, seems to be less paramount compared to cluster B and C personality disorders. Many family- and twin-based genetic studies convincingly stress a close link between schizotypal personality disorder and schizophrenia. This link is less pronounced for paranoid personality disorder, and even vanishingly low for schizoid personality disorder. From a perspective of schizophrenia spectrum disorders a vast amount of data from molecular genetic, neurobiological, neuropsychological and psychosocial research has impressingly confirmed this link for schizotypal personality disorder. Major research deficits, however, have to be noticed for paranoid and schizoid personality disorder.

Taxometric analyses of paranoid and schizoid personality disorders.

There remains debate about whether personality disorders (PDs) are better conceptualized as categorical, reflecting discontinuity from normal personality; or dimensional, existing on a continuum of severity with normal personality traits. Evidence suggests that most PDs are dimensional but there is a lack of consensus about the structure of Cluster A disorders. Taxometric methods are adaptable to investigating the taxonic status of psychiatric disorders. The current study investigated the latent structure of paranoid and schizoid PDs in an epidemiological sample (N=43,093) drawn from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) using taxometric analyses. The current study used taxometric methods to analyze three indicators of paranoid PD - mistrust, resentment, and functional disturbance - and three indicators of schizoid PD - emotional detachment, social withdrawal, and functional disturbance - derived factor analytically. Overall, taxometrics supported a dimensional rather than taxonic structure for paranoid and schizoid PDs through examination of taxometric graphs and comparative curve fit indices. Dimensional models of paranoid and schizoid PDs better predicted social functioning, role-emotional, and mental health scales in the survey than categorical models. Evidence from the current study supports recent efforts to represent paranoid and schizoid PDs as well as other PDs along broad personality dimensions.

Taxometric evidence for the dimensional structure of cluster-C, paranoid, and borderline personality disorders.

Despite a lively debate about the dimensional vs. categorical nature of Personality Disorders (PDs), direct empirical tests of the underlying structure are missing for most PDs. Taxometrics can be used to investigate whether latent structures are categorical or dimensional. We investigated the latent structure underlying Avoidant, Dependent, Obsessive-Compulsive, Depressive, Paranoid, and Borderline PD by means of three types of taxometric analyses. SCID-II based DSM-IV PD criterion scores from 1,816 patients from Mental Health and Forensic Institutes, and 63 nonpatients, were analyzed with three types of taxometric analyses. MAMBAC, MAXEIG, and L-MODE taxometric analyses were applied on multiple criteria sets, constituted both on theoretical grounds and randomly. Assumptions for taxometric analyses were generally met. All but two of the 78 taxometric analyses indicated greater evidence for a latent dimensional structure, with better fit of empirical data to dimensional than to taxonic simulations; mean Comparative Curve Fit Index (CCFI) = .23, SD = .09. Only two analyses yielded ambiguous evidence (CCFI in the .40-.60 range) and none indicated taxonic structure.

Paranoid personality has a dimensional latent structure: taxometric analyses of community and clinical samples.

Although paranoid personality is one of the most commonly diagnosed personality disorders and is associated with numerous negative life consequences, relatively little is known about the structural properties of this condition. This study examines whether paranoid personality traits represent a latent dimension or a discrete class (i.e., taxon). In Study 1, the authors conducted taxometric analyses of paranoid personality disorder criteria in a sample of 731 patients participating in the Collaborative Longitudinal Study of Personality Disorders project (Gunderson et al., 2000) who had been administered a semistructured diagnostic interview for personality disorders according to criteria of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994). In Study 2, the authors conducted parallel analyses of the Paranoia scale of the Personality Assessment Inventory (PAI; L. C. Morey, 2007), using data from the PAI community and clinical normative databases. Analyses across both self-report and interview-based indicators offered compelling support for a dimensional structure. Additionally, analyses of external correlates in these data sets suggested that dimensional models demonstrated stronger validity coefficients with criterion measures than did dichotomous models.

[Personality disorders related to schizophrenia]. / Troubles de personnalité liés à la schizophrénie.

Personality disorders related to schizophrenia were described since Kraepelin's works. According to the DMS III-R those disorders are gathered into the A cluster of personality disorders consisting in: schizotypal, schizoid and paranoid personality disorders. Schizotypal and paranoid personalities are biologically linked to schizophrenia and support the concept of "schizophrenia spectrum". Until now such a link is not found between schizoid personality and schizophrenia. Future research in the field of those personality disorders will bring a better knowledge in the pathogenesis of schizophrenia.

The effect of personality on placebo response in panic patients.

Twenty-eight patients who participated as a placebo group in a treatment study of panic disorder were studied to determine the effect of personality on study completion and outcome. Those subjects who completed only 3 weeks had significantly more pathological personality traits than those who continued in the study. For those continuing beyond 3 weeks, there were negative correlations between the paranoid and borderline personality traits and a global outcome measure. Spontaneous panic attacks were not affected by personality.

Dimensions of personality disorder. The DSM-III-R cluster A diagnoses.

The authors adopt a construct validity approach to examine the structural validity of diagnoses of paranoid, schizoid, and schizotypal personality disorders. Systematic descriptions of these diagnoses were developed based on features identified from the literature that were organized using the clinicians' ratings. Each diagnosis was described in terms of a series of behavioral dimensions. Sets of behavioral exemplars were developed to assess each dimension. Dimensions and diagnoses were found to exhibit satisfactory levels of internal consistency that were cross-validated in a general population sample of 274 subjects and a clinical sample of 133 patients with a diagnosis of personality disorder. Some dimensions did not correlate highly with the total diagnosis score. Diagnoses could probably be refined by eliminating these dimensions. The structural relationships between dimensions delineating each diagnosis were explored using factor analysis. Diagnoses were not unifactorial. Instead, each diagnosis was found to be composed of two factors. The factorial structure of each diagnosis was found to be similar in the general population and clinical sample. It is suggested that the results support a dimensional representation of these diagnoses using three dimensions: paranoid behaviors, social avoidance, and perceptual cognitive distortion.

Delusional (paranoid) disorders.

The group of paranoid or delusional disorders, although not nearly as common as the mood and schizophrenic disorders, may be much more frequent than has usually been thought. DSM-IIIR has made a decisive step in recognizably defining at least one group of them. Interestingly, this change partly came about because the advent of an effective treatment helped to define that group more clearly. Nevertheless, DSM-IIIR's classification is too restrictive, and it was wrong to exclude the diagnosis of paraphrenia. Cases fitting this description will have to be consigned to the category of Psychotic Disorder NOS, which will inevitably be a grab-bag of mixed diagnoses. Also, DSM-IIIR does not emphasize the link between the delusional disorders and paranoid schizophrenia, and the somewhat less well defined overlap with affective disorders, both of which give rise to much diagnostic confusion and inappropriate treatment. Precise history taking and mental status examination and, above all, an up-to-date knowledge of their existence are essential to the recognition and appropriate treatment of the delusional disorders.

Classification of chronic psychoses including delusional disorders and schizophrenias.

A classification of chronic psychoses including nonparanoid schizophrenia, paranoid schizophrenia, paranoid state and paranoia (delusional disorder) is presented. This classification is dependent on a systematic increase in number of symptoms with each group. In particular, delusional disorder is examined with regard to family history. It is clear from the data which are presented that delusional disorder is more likely to be associated with a family history of such traits as suspiciousness, jealousy, secretiveness, and the presence of paranoid behavior or delusions. There is evidence that such familial traits are not seen in schizophrenia, only in delusional disorder.