[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.

Genetic and environmental influences on schizotypy among adolescents in Taiwan: a multivariate twin/sibling analysis.

This study aimed to examine the relative contribution of genes and environment to psychometrically measured schizotypy and the causes for the covariation between different dimensions of schizotypy in a total of 330 pairs of twins and 36 same-sex sib-pairs aged 12-16 and systematically recruited from junior high schools in Taipei. Twins' zygosity was determined by a combination of DNA typing and physical similarity. Schizotypy was measured using the Perceptual Aberration Scale (PAS) as well as the Schizotypal Personality Questionnaire (SPQ) and its three factors (Cognitive-perceptual Dysfunction, Disorganization, and Interpersonal Dysfunction). Univariate analyses of structural equation modeling using Mx program showed that scores on these schizotypal measures were substantially heritable (h (2) ranging from 41 to 49%), with some genetic effects being non-additive. Multivariate analyses revealed common genetic factors linking between various traits of schizotypy, with bivariate heritability ranging from 50 to 65%. The proportion of the genetic contributions not shared with the other measures of schizotypy ranged from 24% for the Disorganization to 49% for the PAS scores. We concluded that there exist both common and specific genetic factors between the various dimensions of schizotypy, and at least half of their correlations were genetic in nature.

Dimensional representations of DSM-IV cluster A personality disorders in a population-based sample of Norwegian twins: a multivariate study.

BACKGROUND: The 'odd' or 'Cluster A' personality disorders (PDs) - paranoid, schizoid and schizotypal PDs - were created in DSM-III with little empirical foundation. We have examined the relationship between the genetic and environmental risk factors for dimensional representations of these three personality disorders. METHOD: These personality disorders were assessed using the Structured Interview for DSM-IV Personality (SIDP-IV) in 1386 young adult twin pairs from the Norwegian Institute of Public Health Twin Panel. Using Mx, a single-factor independent pathway twin model was fitted to the number of endorsed criteria for the three disorders. RESULTS: The best-fit model included genetic and unique environmental common factors and genetic and unique environmental effects specific to each personality disorder. Total heritability was modest for these personality disorders and ranged from 21% to 28%. Loadings on the common genetic and unique environmental factors were substantially higher for schizotypal than for paranoid or schizoid PD. The proportion of genetic liability shared with all Cluster A disorders was estimated at 100, 43 and 26% respectively for schizotypal, paranoid and schizoid PDs. CONCLUSION: In support of the validity of the Cluster A construct, dimensional representations of schizotypal, paranoid and schizoid PD are all modestly heritable and share a portion of their genetic and environmental risk factors. No evidence was found for shared environmental or sex effects for these PDs. Schizotypal PD most closely reflects the genetic and environmental liability common to all three Cluster A disorders. These results should be interpreted in the context of the limited power of this sample.

Validity and reliability of the CAPE: a self-report instrument for the measurement of psychotic experiences in the general population.

OBJECTIVE: General population longitudinal cohort studies have demonstrated the prognostic validity of self-reported psychotic experiences, but data on reliability and cross-validation with interview-based measures of these experiences are sparse. This study tested the reliability and validity of the Community Assessment of Psychic Experiences (CAPE42). METHOD: At baseline, the CAPE42 was used to measure the subclinical psychosis phenotype in a general population sample (n = 765). At follow-up (mean interval: 7.7 months), the Structured Interview for Schizotypy, Revised (SIS-R), the Brief Psychiatric Rating Scale (BPRS), and the CAPE42 were administered (n = 510). RESULTS: Baseline self-reported dimensions of psychosis were specifically and independently associated with their equivalent interview-based dimension at follow-up (standardized effect sizes of 0.4-0.5) and with their equivalent self-reported measure (standardized effect sizes of 0.6-0.8). CONCLUSION: The results indicate that self-reported dimensions of psychotic experiences in general population samples appear to be stable, reliable and valid.

Validity of the family history method for diagnosing schizophrenia, schizophrenia-related psychoses, and schizophrenia-spectrum personality disorders in first-degree relatives of schizophrenia probands.

This study examined the validity of the family history method for diagnosing schizophrenia, schizophrenia-related psychoses, and schizophrenia-spectrum personality disorders in first-degree relatives of schizophrenia probands. This is the first large-scale study that examined the validity of the family history method for diagnosing DSM-III-R personality disorders. The best estimate DSM-III-R diagnoses of 264 first-degree relatives of 117 adult-onset schizophrenia probands based on direct structured diagnostic interviews, family history interview, and medical records were compared to Family History Research Diagnostic Criteria (FH-RDC) diagnoses based on the NIMH Relative Psychiatric History Interview and to family history Structured Clinical Interview for DSM-III-R: Personality Disorders (SCID-II) diagnoses based on the SCID-II adapted to a third person format. Diagnoses of relatives were made blind to proband diagnostic status. The median sensitivity for schizophrenia and the related psychoses was 29% (range 0-50%), the median specificity 99% (range 98-100%), and the median positive predictive value (PPV) 67% (range 20-80%). The median sensitivity for the personality diagnoses was 25% (range 14-71%), the median specificity 100% (range 99-100%), and the median PPV 100% (range 67-100%). The family history method has low sensitivity but has excellent specificity and PPV for schizophrenia, schizophrenia-related psychoses, and schizophrenia-spectrum personality disorders. The kappa coefficient for the family history method was moderately good for the psychoses (0.598) and for paranoid and schizotypal personality disorder (0.576). Using the family history method, the validity of making schizophrenia-related personality disorder diagnoses was comparable to that of making psychotic disorder diagnoses.

Serotonin transporter gene polymorphism and schizoid personality traits in the patients with psychosis and psychiatrically well subjects.

BACKGROUND AND OBJECTIVES: serotonin transporter (5-HTT) gene allelic variants were shown to be associated with Neuroticism and Harm Avoidance but the results were not replicated in other studies. The current investigation was undertaken in a further attempt to study the relationship between 5-HTT polymorphism and personality traits. SUBJECTS AND METHODS: to evaluate a spectrum of personality traits, MMPI was administered to a sample including patients with affective disorders (n=114), patients with schizophrenia spectrum illnesses (n=110) and psychiatrically well controls (n=124). All groups were genotyped for VNTR-17 and functional insertion-deletion (5-HTTLPR) polymorphisms. RESULTS: an association was found between 5-HTTLPR polymorphism and scores on three MMPI scales: Psychopathic deviance, Paranoia and Schizophrenia in patients with affective disorders and S chizophrenia in normal subjects. Both affected and control individuals with 'ss' genotype exhibited lower scores on these scales. CONCLUSION: we demonstrated that functional deletion/insertion allelic variation associated with decreased expression of serotonin transporter ('s' allele or 'ss' genotype) may restrict expression of schizoid traits in normal subjects and patients with affective disorders.

Morbidity risk of psychiatric disorders among the first degree relatives of schizophrenia patients in Taiwan.

This study aimed to assess the boundaries of the schizophrenia spectrum and whether inclusion of such phenotypes increases power for linkage analysis of schizophrenia. Participants were 234 first degree relatives (FDRs) of 94 schizophrenia probands in Northern Taiwan who completed a direct interview using the Diagnostic Interview for Genetic Studies (DIGS). Based on best estimate diagnosis, the morbidity risk in the relatives for schizophrenia was 2.5 percent (Weinberg's shorter method) or 3.9 percent (Kaplan-Meier estimate). Depending on the stringency of diagnosis, lifetime prevalence was 2.6 percent to 4.7 percent for schizotypal personality disorder, 3.4 percent to 8.6 percent for paranoid personality disorder, and 1.3 percent to 3.4 percent for schizoid personality disorder. These figures are significantly higher than the corresponding figures in the general population. However, none of the recurrence risk ratio for any spectrum that included both schizophrenia and a personality disorder (3.0 to 5.9) was greater than that of schizophrenia alone (9.3 to 14.4). Thus, including schizophrenia-related personality disorders in the spectrum did not increase power for linkage analysis of schizophrenia.

Smooth pursuit eye movements to extraretinal motion signals: deficits in relatives of patients with schizophrenia.

BACKGROUND: Although mounting evidence supports the idea that smooth pursuit abnormality marks the genetic liability to schizophrenia, the precise ocular motor mechanism underlying the abnormality remains unknown. Based on recent findings in schizophrenia, we hypothesize that subtle deficits in the ability to hold online and/or use extraretinal motion information underlie the pursuit abnormality in vulnerable individuals. METHODS: The hypothesis was tested in 69 first-degree, biological relatives of probands with schizophrenia; 26 relatives had schizophrenia spectrum personalities (SSP). Subjects recruited from the community (n=71; 29 with SSP), without a known family history of psychosis, constituted the comparison groups. The traditional smooth pursuit gain measure, which is a ratio of smooth pursuit eye velocity in response to both retinal and extraretinal motion signals and the target velocity, was obtained. In addition, newly developed measures of predictive smooth pursuit (ie, in the presence of only extraretinal motion signals) were obtained. The latter measures were evaluated after the current retinal motion signals were made unavailable by briefly making the target invisible. RESULTS: Relatives, particularly those with SSP, showed significantly poorer predictive pursuit response to extraretinal motion signals (F(2,136)=6.51, P<.005), compared with the community subjects. However, the traditional smooth pursuit gain in response to both retinal and extraretinal motion signals was not different between groups. CONCLUSIONS: These results suggest that relatives of patients with schizophrenia, particularly those with SSP, have specific deficits in predictive pursuit based on only extraretinal motion signals. Normal smooth pursuit gain in response to both retinal and extraretinal motion signals is likely due to compensation based on retinal motion information. The latter suggests normal retinal motion processing and smooth pursuit motor output.

Clinical description of an adult male with psychosis who showed FMR1 gene methylation mosaicism.

Unstable trinucleotide repeat DNA contained in numerous genes has been proposed as the underlying mechanism in the clinical phenomenon of genetic anticipation in fragile X syndrome and other neurodegenerative diseases. No clear evidence has been found for the role of these abnormal trinucleotide repeat expansion-containing genes in schizophrenia or other psychiatric disorders. This report describes an adult male with psychosis who was later found to have methylation mosaicism of the FMR1 gene. We discuss history, examination, and investigation which led to the diagnosis and treatment response of this patient.

Association of polymorphisms of dopamine D2 receptor (DRD2), and dopamine transporter (DAT1) genes with schizoid/avoidant behaviors (SAB).

The dopaminergic system, and in particular the dopamine D2 receptor, has been implicated in reward mechanisms in the brain. Dysfunction of the D2 dopamine receptors leads to aberrant substance-seeking behaviors (ethanol, drugs, tobacco, and food) and other related behaviors (pathological gambling, Tourette's disorder, attention-deficit/hyperactivity disorder). This is the first study supporting a strong association between the dopamine D2 receptor Taq A1 allele with schizoid/avoidant behavior (SAB). Additionally, an albeit weaker association between the 480-bp VNTR 10/10 allele of the dopamine transporter (DAT1) gene with SAB was similarly found.

The relationship between cognitive functions and behavioral deviance in children at risk for psychopathology.

Previous studies have generally found that children at risk for psychopathology (i.e. children characterized by risk factors such as parental psychopathology and maltreatment) display more deviant behavior and cognitive dysfunctions than children not at risk. The present study examined the relationship between behavioral deviance and cognition in children characterized by a variety of risk factors (parental schizophrenia, parental psychiatric disorders other than schizophrenia, parental maltreatment). The results indicated that the effects of parental schizophrenia could be distinguished from the more generalized effects of maltreatment and that cognitive deficits were associated with schizoid behavior in children at risk for schizophrenia. These findings suggest that cognitive ability may serve as a moderator of vulnerability to maladjustment in children at risk for schizophrenia.

A family study of schizotypal disorder.

Direct, blind interviews were used to study the risk for and prevalence of DSM-III-R Axis I and II disorders in 93 first-degree relatives of outpatients with schizotypal personality disorder (SPD) and outpatients with other personality disorders. Risks for SPD (at a slightly loosened diagnostic threshold) and schizoid personality disorder were significantly higher in the families of probands with SPD. Schizophrenia was present only among relatives of probands with SPD, accounting for a morbid risk of 4.1 percent. Neither familial risks for mood and anxiety disorders nor the prevalence of other Axis II disorders significantly differed in the two groups of relatives. It is suggested that SPD is a familial disorder representing a phenotypic expression of liability to schizophrenia.

Personality variations in healthy relatives of schizophrenics.

A familial relationship between schizophrenia and schizotypal personality disorder is widely acknowledged; the familial relationship between schizophrenia and the broad continuum of schizoid personality variation is less clear. In a comprehensive family study healthy relatives of schizophrenics were compared by self rated personality features with relatives of unipolar depressed patients and with relatives of controls. The dimension of schizoidia was not able to distinguish the groups of relatives. However, relatives of schizophrenics (in particular male relatives) scored higher on 'normalized' personality dimensions such as 'rigidity' and 'neuroticism'. Healthy relatives of probands with unipolar depression revealed a similar deviant pattern.

The New York High-Risk Project: anhedonia, attentional deviance, and psychopathology.

In the New York High-Risk Project (NYHRP) we followed subjects at risk for schizophrenic or affective disorders and low-risk controls from childhood to adulthood, with the goal of identifying early predictors of later schizophrenia-related psychopathology. In this article, we focus on two potential predictors: the Physical Anhedonia Scale administered in adolescence and the Attention Deviance Index obtained in childhood. Subjects of this report are 161 members of the NYHRP's first sample (sample A), who had scores on both attention and anhedonia and had followup clinical assessments in adulthood. We used a path analysis model and several separate regression analyses to examine the relationships of the parent diagnostic groups, attentional dysfunction, and anhedonia to each other and to each of three psychopathological outcomes: schizophrenia and schizophrenia-related psychoses, major affective disorder, and social isolation in nonpsychotic subjects. Subject groups did not differ in anhedonia scores but did differ in childhood attentional dysfunction, psychosis, and social isolation, all of which are more common in subjects at risk for schizophrenia. In these subjects at risk for schizophrenia, but not in the other two groups of subjects, childhood attentional dysfunction is related to anhedonia, social isolation, and possibly nonparanoid psychosis. Anhedonia is associated with social isolation and with psychosis in females. Several other gender effects are also noted.

Psychiatric illnesses in families of subjects with schizophrenia-spectrum personality disorders: high morbidity risks for unspecified functional psychoses and schizophrenia.

OBJECTIVE: The authors determined morbidity risks for psychiatric illnesses in the families of probands with schizophrenia-spectrum personality disorders. METHOD: Subjects were recruited from the community through newspaper advertisements. Subjects were identified as having schizophrenia-spectrum personality disorders (N = 30) if they met at least three, four, or three DSM-III-R criteria for schizoid (N = 14), schizotypal (N = 20), and/or paranoid (N = 15) personality disorder, respectively. The comparison subjects had no psychiatric diagnoses (N = 8) or had other personality disorders (N = 12); none of the subjects in either group had any DSM-III-R axis I diagnosis. Trained interviewers collected family history information about the relatives of the two groups; the interviewers were blind to the probands' diagnoses. RESULTS: The risks for schizophrenia, other functional psychoses, and schizophrenia-spectrum personality disorders were significantly higher in the relatives of subjects with schizophrenia-spectrum personality disorders than in the families of the comparison subjects. CONCLUSIONS: The high rate of schizophrenia in the families of probands with schizophrenia-spectrum personality disorders is consistent with the previous findings of higher than normal rates of these personality disorders in the biological relatives of schizophrenic patients. The significance of the high rate of unspecified functional psychoses is unclear. Use of the family study method, by which valid differential diagnosis of psychoses is possible, is indicated. The results from the current study do not rule out the possibility that the schizophrenia-spectrum personality disorders are related to psychoses in general rather than specifically to schizophrenia.

Psychiatric illness in first degree relatives of Nigerian schizophrenic and surgical control patients.

Psychiatric morbidity risk was assessed in 293 first degree relatives of patients with schizophrenia and 277 first degree relatives of surgical control patients using the family history method (FH-RDC). The morbidity risk for schizophrenia, alcoholism and schizoid personality disorder was significantly greater in relatives of schizophrenic patients. Affective disorder was difficult to diagnose using the family history method. Of the relatives of the schizophrenic probands who had psychotic illness 73.3% received treatment from traditional healers. The problem of social stigmatization of psychiatric illness was a deterrent to obtaining adequate family history, invariably the most reliable informant was the index proband. The problem was compounded by the paucity of and inaccessibility to treatment records from the traditional healers.

Genetic transmission and improved diagnosis of schizophrenia from pedigrees of adoptees.

In previous investigations of the prevalence of schizophrenic illness among the biological relatives of schizophrenic adoptees in Copenhagen and the remainder of Denmark, the operation of heritable spectrum illness was clearly implicated. The findings supporting that conclusion are briefly summarized. Classical chronic schizophrenia was found almost exclusively in the biological relatives of chronic schizophrenic probands and its prevalence was ten times greater than that in the biological relatives of controls. These were global diagnoses, made without knowledge of the relationships and family histories of the subjects, and based upon the descriptions of dementia praecox or schizophrenia by Kraepelin and Bleuler. They showed considerably greater sensitivity and at least equal specificity in comparison with diagnoses made on the same material in accordance with operational criteria as exemplified by DSM-III. The prevalence of a disorder in the biological relatives of adoptees with that disorder in comparison with biological relatives of control adoptees offers a useful test for the expression of genetic factors in the disorder, but also a much needed evaluation of the validity of diagnoses based on clinical observation.

Personality characteristics of parents of autistic children: a controlled study.

Parents of 21 autistic children and of 21 children with other handicaps, matched for sex, age, IQ and father's occupation, were interviewed with a schedule known to discriminate between schizoid and non-schizoid people. Ratings were reliable and the interviewers remained "blind". Parents of autistic children, especially fathers, were significantly more often rated as having schizoid traits. They were also more intellectual.

[Late endogenous psychoses in light of clinico-genealogic research]. / Pozdnie éndogennye psikhozy v svete kliniko-genealogicheskikh issledovanii.

The families of 170 probands with late manifest endogenic psychoses (schizophrenia and manic-depressive psychoses) were studied. Late schizophrenia was found to be genetically related to schizophrenia on the whole. The families of patients with late schizophrenia were characterized by accumulation of typical schizophrenic psychoses and schizoid anomalies of the character. In the parents and siblings of such patients the rate of schizophrenia was significantly lower than in the families of patients with early manifestations. In the children of probands the risk of schizophrenia development was approximately identical in both late and early manifestations. The families of patients with late manic-depressive psychosis presented the accumulation of both affective and schizophrenic psychoses. The frequency of the latter grew from generation to generation.

[Family background of patients with slowly progressive childhood schizophrenia with a syndrome of pathologic fantasizing]. / Semeinyi fon probandov, bol'nykh maloprogredientnoi detskoi shizofreniei s sindromom patologicheskogo fantazirovaniia.

The authors studied the familial background of 50 probands suffering from slowly progressive infantile schizophrenia with the morbid fantasy making syndrome. A total of 110 firstkin relatives (100 parents and 10 siblings) were examined. The incidence of manifest psychoses in parents was 16% (8 persons) in the first group of probands and 6% (3 persons) in the second group. "Subclinical forms of psychosis" and personality abnormalities of the type of sthenic schizoids were also prevalent among the relatives of the second group probands (22% and 28%, respectively). Parents denoted as schizoids with a marked emotional defect were present only in the families of the Group I probands (10%) while individuals of a hyperthymic type were observed only in the families of Group 2 probands (16%). Parents considered as normal were markedly prevalent among the relatives of Group I probands (16% and 6%, respectively).