Schizotypal personality disorder inside and outside the schizophrenic spectrum

The concept of schizotypal personality disorder has been heavily discussed since its introduction into the official classification of mental disorders in DSM-III. The aim of this study was to investigate the difference between schizotypal personality disorder within and outside the genetic spectrum of schizophrenia. Schizotypals with and without schizophrenic cotwins and first-degree relatives were compared, with individuals with other mental disorders and no mental disorders as controls. It appeared that only inadequate rapport and odd communication were more pronounced among schizotypals within, compared to schizotypals outside the schizophrenic spectrum. Schizotypals outside the schizophrenic spectrum, however, scored higher than schizotypals inside the schizophrenic spectrum on ideas of reference, suspiciousness, paranoia, social anxiety, self-damaging acts, chronic anger, free-floating anxiety and sensitivity to rejection. Interestingly, the four last features are seldom observed among schizotypals inside the schizophrenic spectrum. Monozygotic non-schizophrenic cotwins of schizophrenics score high on inadequate rapport, odd communication, social isolation and delusions/hallucinations. Monozygotic non-schizophrenic cotwins of schizotypals outside the schizophrenic genetic spectrum score high on illusions, depersonalization, derealization and magical thinking. Negative schizotypal features appear to be inside the schizophrenic spectrum, while positive borderline-like features are outside having another genetic endowment.     

Personality disorder in the families of depressed, schizophrenic, and never-ill probands

In a blind family study of 176 probands with nonpsychotic major depression, psychotic major depression, schizophrenia, or no history of DSM-III disorders, only the relatives of depressed probands with mood-incongruent psychotic features had a risk for personality disorders higher than that for the relatives of never-ill probands. The authors did not find a high rate of borderline personality in relatives of depressed probands or of schizotypal personality disorder in relatives of probands with schizophrenia or any psychosis. However, depressed probands with normal dexamethasone test results had a significantly higher familial loading for the DSM-III cluster of histrionic, antisocial, borderline, and narcissistic personality disorders.     

An independent analysis of the Danish Adoption Study of Schizophrenia. VI. The relationship between psychiatric disorders as defined by DSM-III in the relatives and adoptees

In this report, modified DSM-III criteria were applied to all the available interviews with adoptees from the greater Copenhagen sample of the Danish Adoption Study of Schizophrenia. In the adoptees, reasonable agreement was found between our DSM-III diagnoses and the original diagnoses using global DSM-II-based criteria by Kety et al for their categories of chronic and acute, but not borderline, schizophrenia. Comparing DSM-III-based diagnoses in adoptees and relatives, schizophrenia, schizotypal personality disorder, and paranoid personality disorder were all significantly more common in the biologic relatives of schizophrenic v screened control adoptees. These three diagnoses, which together form a tentative "schizophrenia spectrum," were also significantly concentrated in the biologic relatives of adoptees with schizoaffective disorder, mainly schizophrenic subtype, and schizotypal personality disorder, but not in biologic relatives of adoptees with schizophreniform disorder or atypical psychosis.     

Increased morbid risk for schizophrenia-related disorders in relatives of schizotypal personality disordered patients

To evaluate whether probands from a clinical sample diagnosed as having DSM-III schizotypal and/or paranoid personality disorder have a familial relationship to the schizophrenia-related disorders, the morbid risk for schizophrenia-related disorders and other psychiatric disorders were evaluated in the first-degree relatives of patients with schizotypal and/or paranoid personality disorder and compared with the corresponding risk for these disorders in the first-degree relatives of patients with other non-schizophrenia-related personality disorders. The morbid risk for all schizophrenia-related disorders, and specifically for schizophrenia-related personality disorders, was significantly greater among the relatives of the probands with schizotypal and/or paranoid personality disorder than among the relatives of probands with other personality disorder. The morbid risk for other psychiatric disorders did not differ significantly between the first-degree relatives of the schizotypal/paranoid personality disorder and the other personality disorder control proband samples. These results suggest a specific familial association between schizophrenia-related disorders, particularly schizophrenia-related personality disorders, and clinically diagnosed schizotypal patients.     

Diagnostic approaches to schizotypal personality disorder: a historical perspective

The goal of this article is to provide a historical perspective on the DSM-III concept of schizotypal personality disorder. It is argued that two major traditions have influenced our conceptualization of this diagnostic entity. The first or familial approach emphasizes the characteristic traits found in the deviant but nonpsychotic relatives of schizophrenics. The second or clinical approach focuses on patients who appear to demonstrate the fundamental symptoms of schizophrenia without psychotic symptoms or severe personality deterioration. A review of these two traditions concludes that while similar in some regards, they also differ in important ways in their views on the characteristics of the true "schizotype." The impact of these two traditions is then traced through the Danish Adoption Studies of Kety et al. to the development of the DSM-III criteria for schizotypal personality by Spitzer, Endicott, and Gibbon. Finally, the article reviews recent studies on the validity of specific criteria for schizotypal personality disorder (SPD) and reassesses the conceptual issue about the nature of the relationship of SPD to schizophrenia on the one hand and to other personality disorders on the other.     

Familial association of schizotypal traits with psychotic and affective disorders

The criteria for schizotypal personality disorder were developed on the basis of traits observed in biologic relatives of schizophrenic and borderline schizophrenic probands from the Danish adoption studies. In this review, the relationship between schizotypal personality disorder and the schizophrenic spectrum, affective disorders, and psychotic disorders is explored. A dimension of psychosis may overlap with the schizophrenia spectrum to yield chronic schizophrenia, with the affective disorders spectrum to yield psychotic affective disorder, or by itself lead to other psychotic disorders. Schizotypal personality disorder in this model is posited to represent schizophrenia spectrum disorder that does not overlap with psychosis, whereas nonpsychotic affective disorders represent the affective disorders that do not overlap with psychosis. Delusional disorder represents another psychotic disorder that is not specifically related to either schizophrenia or the affective disorders. Evidence suggests that the schizotypal personality disorder criteria, particularly those emphasizing the negative symptoms or deficit-like symptoms of this disorder, specifically identify a unique relationship to the schizophrenia spectrum.     

A family study of schizophrenic and normal control probands: implications for the spectrum concept of schizophrenia

Morbidity risks for mental illness were determined in 750 first-degree relatives of chronic schizophrenic and normal control probands. Psychiatric disorders that were more frequent in relatives of schizophrenic probands than in relatives of normal control probands were chronic schizophrenia (5.8% versus 0.6%), schizotypal personality disorder (definite, 14.6% versus 2.1%; probable, 12.1% versus 6.5%), and paranoid personality disorder (7.3% versus 2.3%). The data suggest that schizotypal and paranoid personality disorders are genetically related to schizophrenia. The implications for schizophrenia research are discussed.     

Psychiatric disorders in the families of schizotypal subjects.

In a study of the families of 21 schizotypal patients, we found an increased morbidity risk for schizophrenia compared with that in the families of 21 nonschizotypal patients and 42 controls. The Axis I diagnoses did not influence the distribution of the morbidity risk in the families of the schizotypal patients. If the schizotypal subjects also had other personality disorders, the morbidity risk for schizophrenia among their relatives was lower, although not significantly.     

Differential perception of parental bonding in schizotypal and borderline personality disorder patients.

Fifty-four patients with schizotypal and/or borderline personality disorders were compared with 165 patients with other personality disorders and 52 patients with no personality disorders as to their perception of parental behavior in childhood. Both schizotypals and borderlines reported low care; however, schizotypals remembered underprotection and borderline overprotection. The study suggests parental neglect in the childhood memory of schizotypals and negative over-involvement for borderlines.     

Risk of schizophrenia in character disordered patients

Inpatients from the Chestnut Lodge follow-up study diagnosed with character disorder were studied to predict future schizophrenic decompensation. Individually, three DSM-III criteria for schizotypal personality disorder predicted schizophrenia at long-term follow-up: magical thinking, suspiciousness or paranoid ideation, and social isolation. Additionally, lower IQ, poorer premorbid quality of work, and transient delusional experiences were predictive. No borderline personality disorder criterion was predictive. This suggests that schizotypal but not borderline personality disorder belongs in the schizophrenic spectrum. Within schizotypal personality disorder, criteria from both familial and clinical traditions appear to be dimensions of vulnerability to psychosis.     

Toward a validation of the concept of borderline schizophrenia

The concept of borderline schizophrenia has survived in DSM-III under the term schizotypal personality disorder. First-generation studies of borderline schizophrenia have focused on phenomenological criteria for delineation of the syndrome. Four diagnostic systems have been published but no external validation is offered, hence, their use is limited. Two published studies give prevalence rates of 12.7% and 24.5% among first-degree relatives of schizophrenics. A second generation of studies focusing on biologic dysfunctions already described in schizophrenic populations but targeting high-risk individuals, like the first-degree relatives of schizophrenics, will provide external validation for the diagnosis of Borderline Schizophrenia. Six areas for study are suggested: biochemical, brain morphology, psychophysiological, electroencepholographic, neuroendocrine, and neuromuscular. A clinicobiologic dissection would provide the biologic underpinning for the diagnosis of borderline schizophrenia. To date, only platelet and plasma MAO levels among first-degree relatives have been studied. The heuristic value of this model is discussed.     

Modulation of the startle response and startle laterality in relatives of schizophrenic patients and in subjects with schizotypal personality disorder: evidence of inhibitory deficits

OBJECTIVE: Patients with schizophrenia spectrum disorders have been shown to have deficits in sensorimotor gating as assessed by prepulse inhibition of the startle response. The authors hypothesized that nonschizophrenic relatives of patients with schizophrenia would also have prepulse inhibition deficits, thereby reflecting a genetically transmitted susceptibility to sensorimotor gating deficits. METHOD: Twenty-five comparison subjects, 23 patients with schizophrenia, 34 relatives of the schizophrenic patients, and 11 subjects with schizotypal personality disorder were assessed in an acoustic startle paradigm. The eye-blink component of the startle response was assessed bilaterally by using electromyographic recordings of orbicularis oculi. RESULTS: The patients with schizophrenia, their relatives, and subjects with schizotypal personality disorder all had reduced prepulse inhibition relative to comparison subjects, and these deficits were more evident in measures of right eye-blink prepulse inhibition. Comparison subjects demonstrated greater right versus left eye-blink prepulse inhibition, whereas the probands, their relatives, and subjects with schizotypal personality disorder showed less asymmetry of prepulse inhibition. CONCLUSIONS: These data suggest a genetically transmitted deficit in prepulse inhibition (sensorimotor gating) in patients with schizophrenia spectrum disorders, including subjects with schizotypal personality disorder and relatives of patients with schizophrenia.     

Frontal release signs among patients with schizophrenia, their first-degree biological relatives, and non-psychiatric controls

BACKGROUND: Frontal release signs (FRS) are a subset of neurological soft signs that are overrepresented among patients with schizophrenia and their unaffected relatives and may be correlated with neuropsychological functioning and chronicity of illness. This study sought to explore FRS and their associations with verbal memory and symptoms of schizophrenia in an African American sample of patients, and FRS and their associations with verbal memory and schizotypal features among first-degree relatives and non-psychiatric controls. METHOD: FRS, verbal memory, schizophrenia symptoms (in patients), and schizotypal features (in relatives and controls) were assessed in 63 patients with schizophrenia and related disorders, 33 of their unaffected first-degree relatives, and 51 controls. RESULTS: Patients and their relatives displayed greater FRS than controls. Among relatives and controls, greater FRS were related to greater self-reported disorganized and interpersonal features of schizotypal personality disorder. FRS were not associated with patients' schizophrenia symptoms in the expected direction. In the entire sample, greater FRS were associated with poorer verbal working memory. CONCLUSIONS: Because they are easy to assess, may be correlated with neuropsychological functioning, and appear to covary with level of genetic diathesis for schizophrenia, the study of FRS may shed light on the neurodevelopmental processes that underlie schizophrenia.     

Mental disorders in first-degree relatives of schizophrenics

A total 215 first-degree relatives of 88 twin probands with schizophrenia, mood disorders and nonaffective psychoses were studied. The twins' parents and siblings were personally interviewed with structured diagnostic instruments and diagnosed in accordance with DSM-III-R criteria. The first-degree relatives were interviewed by interviewers who were blind to the twins' diagnoses. Schizophrenia and schizotypal personality disorder were significantly more frequent in first-degree relatives of schizophrenic twins. Respectively, anxiety and mood disorders were significantly more prevalent among the parents and siblings of probands with mood disorders. Schizophrenic spectrum disorders were significantly more common in the families of schizophrenic probands compared with relatives of mood disorder probands, thus confirming a relationship between schizophrenia and schizophrenic spectrum disorders. However, we cannot, based on our study, specify whether this relationship is caused by genetic or environmental factors.     

Schizotypal symptoms in the relatives of schizophrenia patients: an empirical analysis of the factor structure

This study examined the nature of schizotypal symptoms in the relatives of schizophrenia patients and investigated phenomenological differences in symptomatology manifested by a familial sample and a clinical sample of personality disorder patients. Confirmatory factor analyses were used to test models of DSM-III-R schizotypal symptoms in the first degree relatives (n = 172) of schizophrenia patients. A multisample analysis was conducted to determine whether the same model adequately described the schizotypal symptoms rated in the relatives of schizophrenia patients and in clinically selected personality disorder patients. The results indicated that a three-factor model consisting of cognitive/perceptual, interpersonal, and disorganization factors yielded the best fit to the data from the relatives of schizophrenia patients, but that this model did not adequately describe both the relatives of schizophrenia patients and personality disorder patients. These findings indicate that the structure of schizotypal symptoms in the relatives of schizophrenia patients is similar to the three-factor model of schizophrenia symptoms often reported, but not the same as the structure of schizotypal symptoms in clinically selected personality disorder patients.     

The schizotypal personality disorder: historical origins and current status

BACKGROUND: The schizotypal personality disorder is a recent psychiatric nosological concept developed by Spitzer at the end of the 1970s, based on the analysis of the characteristics of relatives of schizophrenic subjects included in the adoption studies carried out in the same decade by Kety, Wender and Rosenthal. HISTORICAL ASPECTS: However, this entity is based on older observations, at the beginning of the past century, showing common behavioural characteristics in relatives of schizophrenics. Its status within our current nosography remains dubious, sometimes classified among personality disorders, sometimes in the schizophrenia spectrum disorders. It is interesting to present the origins of this concept that stem from two complementary approaches: a family approach and a clinical approach of sporadic cases and then to redefine the framework within which the diagnostic approach was based and its continuity, up until our current classifications, the DSM and CIM. CURRENT STATUS: The historical origins cannot summarize the disorder and it appears important to redefine the multidimensional characteristics of the schizotypal personality disorder, generally a three-factor model. Indeed, dimensional models of psychosis are becoming established as conceptually and clinically useful. Recent studies on the dimensionality of psychosis show an evolution of the schizotypal concept, initially defined as being part of the schizophrenia spectrum and which now appears to be more broadly linked to a concept of unitary psychosis, including the bipolar disorder. CONCLUSION: Dimensions of psychosis seem to be associated with different familial aggregation and risk of psychosis, suggesting that they are underlined by different physiopathological processes. Hence, the dimensional approach can help to disentangle the genetic heterogeneity of the disease.     

Sensory gating deficits assessed by the P50 event-related potential in subjects with schizotypal personality disorder

OBJECTIVE: The schizophrenia spectrum includes individuals with schizophrenia, their relatives, and individuals with schizotypal personality disorder. Subjects in the schizophrenia spectrum have disorders of attention, cognition, and information processing. Attention and information processing can be assessed by testing suppression of the P50 event-related potential; the amplitude of the P50 wave is measured in response to each of two auditory clicks. In normal subjects, the P50 wave following the second click is suppressed, or "gated." Schizophrenic patients and their relatives show less suppression of the second P50 wave. Deficits in P50 suppression have high heritability and show linkage to the alpha-7 subunit of the nicotinic cholinergic receptor gene in families with schizophrenia, suggesting that deficits in P50 suppression are trait markers for gating abnormalities in schizophrenia spectrum subjects. Although schizotypal subjects have been shown to have deficits in sensorimotor gating as measured by prepulse inhibition, to the authors' knowledge P50 sensory gating in schizotypal personality disorder has yet to be reported. METHOD: P50 suppression in 26 subjects with schizotypal personality disorder and 23 normal subjects was assessed through auditory conditioning and testing. RESULTS: The subjects with schizotypal personality had significantly less P50 suppression than did the normal subjects. CONCLUSIONS: Subjects with schizotypal personality disorder may have trait-linked sensory gating deficits similar to those in patients with schizophrenia and their relatives. Because these subjects may manifest sensory gating deficits without overt psychotic symptoms, it is likely that these deficits represent a core cognitive dysfunction of the schizophrenia spectrum.     

Comparison between personality disorder diagnoses in DSM-III and DSM-III-R: reliability, diagnostic overlap, predictive validity

97 nonpsychotic consecutive day patients were diagnosed by the axis 1 and 2 in the DSM-III and DSM-III-R system, and their treatment response during their stay was measured by the Health Sickness Rating Scale. The interrater reliability was equally good for both diagnostic systems. On axis 1, there were only minor differences between DSM-III and DSM-III-R. On axis 2, the frequency of schizotypal disorder was reduced by 40% and the frequency of histrionic disorder by two-thirds. The number of schizoid disorders increased from zero to five. Of the DSM-III schizotypals who lost this diagnosis in DSM-III-R (n = 8), 4 got a new diagnosis of schizoid personality and 4 maintained their borderline diagnoses. In DSM-III-R there was a sharper demarcation between patients with severe and nonsevere personality disorder with regard to treatment outcome, indicating an increased validity of these categories. There was also a sharper demarcation between borderline versus histrionic and schizotypal, and between schizotypal and schizoid diagnoses.     

Schizotypal dimensions: continuity between schizophrenia and bipolar disorders

BACKGROUND: Family studies have suggested that schizophrenia and bipolar disorders share some susceptibility factors. Schizotypal personality disorder (SPD) may be an intermediate phenotype common both to schizophrenia and bipolar disorders. We explored the familiality of schizotypal dimensions by comparing the magnitude of schizotypal dimensions between schizophrenic and bipolar relatives. We also looked for intra-familial resemblance for these dimensions, and for an increased familial risk of schizophrenia and/or bipolar disorders associated with a particular schizotypal dimension. METHODS: We used the Schizotypal Personality Questionnaire (SPQ) to study the three schizotypal dimensions (disorganization, negative and positive) in a sample of unaffected first-degree relatives of schizophrenic (N=85), psychotic bipolar (N=63) and bipolar (N=32) probands. Differences between groups were tested using a two-tailed t-test or ANOVA for continuous variables and a chi-squared test for discrete variables. We used the intraclass correlation method to study the intra-familial correlation. Linear mixed models were used to measure the familial risk. RESULTS: The disorganization dimension appears to be common to relatives of both schizophrenia and psychotic bipolar disorders, but not in the relatives of non-psychotic bipolar probands. This dimension also increases the familial risk of these two disorders. The negative dimension shows intra-familial resemblance (R=0.29), we failed to observe the expected familiality for the disorganized dimension. CONCLUSIONS: The shared nature of the disorganization dimension shown by a similar familial risk for schizophrenia and psychotic bipolar disorders suggests that same genetic background may underlie psychotic disorders. Although, negative dimension is familial, it is not associated for an increased familial risk for both disorders.