Schizotypal personality disorder or prodromal symptoms of schizophrenia?

Schizotypal personality disorder shares some attenuated phenotypic features with schizophrenia, but represents an independent syndrome. In contrast, prodromal symptoms of schizophrenia represent early warning signs of the impending onset of schizophrenia. Although these constructs are intended to reflect independent syndromes, self-report instruments measuring these constructs assess similar symptoms. It does not appear that existing research has examined the relative discriminant validity of screening instruments for these syndromes. A sample of 998 young adults (68% female; 73% Caucasian), within the age of risk for schizophrenia (ages 18–34; mean 20.4 ± 2.2), met validity criteria after completing online versions of the Abbreviated Schizotypal Personality Questionnaire (SPQ-B) and the 24-item Abbreviated Youth Psychosis at Risk Questionnaire (Y-PARQ-B). Based on clinical cut-off scores used in previous research, 5.2% were [only] considered at heightened risk for psychosis (potentially prodromal), 3.4% had [only] schizotypal personality features, and 2.9% met criteria for both constructs (75% of individuals meeting cutoff for one measure did not meet criteria for the other). Males and younger participants scored significantly higher on both measures. The total scores from the SPQ-B and Y-PARQ-B showed a significant positive correlation (r_s = .66, p < .001, R² = .43); however, 57% of the variance was not shared between the measures. Of the three SPQ-B subscales, Cognitive–Perceptual showed the strongest correlation with Y-PARQ-B. Results suggest that the SPQ-B and Y-PARQ-B have moderate discriminate validity between the overlapping, yet distinct, constructs of schizotypal personality and heightened risk of developing psychosis (potentially prodromal).     

Neurobiological measures of schizotypal personality disorder: defining an inhibitory endophenotype?

OBJECTIVE: Subjects with schizotypal personality disorder demonstrate deficits in inhibition when assessed on prepulse inhibition, P50 suppression, and antisaccade paradigms. This study determined if distinct subgroups of subjects with schizotypal personality disorder could be identified on the basis of performance on these measures and whether endophenotypes could be defined for future genetic study by using measures of inhibitory function. METHOD: Prepulse inhibition, P50 suppression, and antisaccade paradigms were assessed in 21 subjects with schizotypal personality disorder. RESULTS: Seven subjects with schizotypal personality disorder had deficits on each paradigm; seven had no deficits on any paradigm. P50 and antisaccade deficits were present in five of the same subjects and significantly correlated. CONCLUSIONS: These results suggest that P50 and antisaccade performance reflects a common endophenotype and that prepulse inhibition identifies a separate endophenotype reflecting different neurobiological substrate(s) in subjects with schizotypal personality disorder. This pattern may generalize to schizophrenia spectrum disorder patients.     

Schizoaffective disorder: a form of schizophrenia or affective disorder?

BACKGROUND: The diagnostic status of schizoaffective disorder continues to be controversial. Researchers have proposed that schizoaffective disorder represents a variant of schizophrenia or affective disorder, a combination of the 2, or an intermediate condition along a continuum between schizophrenia and affective disorder. METHOD: We compared outpatients aged 45 to 77 years with DSM-III-R diagnosis of schizoaffective disorder (N = 29), schizophrenia (N = 154), or nonpsychotic mood disorder (N = 27) on standardized rating scales of psychopathology and a comprehensive neuropsychological test battery. A discriminant function analysis was used to classify the schizoaffective patients based on their neuropsychological profiles as being similar either to schizophrenia patients or to those with nonpsychotic mood disorder. RESULTS: The schizoaffective and schizophrenia patients had more severe dyskinesia, had a weaker family history of mood disorder, had been hospitalized for psychiatric reasons more frequently, were more likely to be prescribed neuroleptic and anticholinergic medication, and had somewhat less severe depressive symptoms than the mood disorder patients. The schizophrenia patients had more severe positive symptoms than the schizoaffective and mood disorder patients. The neuropsychological performances of the 2 psychosis groups were more impaired than those of the nonpsychotic mood disorder patients. Finally, on the basis of a discriminant function analysis, the schizoaffective patients were more likely to be classified as having schizophrenia than a mood disorder. CONCLUSION: These findings suggest that schizoaffective disorder may represent a variant of schizophrenia in clinical symptom profiles and cognitive impairment.     

How does studying schizotypal personality disorder inform us about the prodrome of schizophrenia?

An increasing emphasis in the schizophrenia literature has been on the prodromal phase of the illness. The study of schizophrenia spectrum illness, including schizotypal personality disorder, has added important insight into the etiology, neuropathology, and treatment of schizophrenia, which can facilitate early identification, intervention, and perhaps prevention of the illness. The heterogeneity of the schizophrenia spectrum makes its definition elusive at best. The primary aim of the Cognitive Assessment and Risk Evaluation Program at the authors’ institution is to combine the current knowledge of clinical and demographic risk factors for schizophrenia with the rapidly emerging data on vulnerability markers, or endophenotypes, that are associated with schizophrenia. The use of brain-based vulnerability markers may help to identify neurobiologically and clinically meaningful subgroups within this heterogeneous population of individuals in the early stages of schizophrenia. Another important aim of the Cognitive Assessment and Risk Evaluation program is to thoroughly assess those individuals who have not converted to psychosis to understand potential protective factors, reduce the rate of false positives, and decrease disability. The current review details a strategy for researching the schizophrenia prodrome by using information gained from research in schizotypal personality disorder.     

"Schizoaffective disorder": an invalid diagnosis? A comparison of schizoaffective disorder, schizophrenia, and affective disorder

The authors compared patients meeting widely accepted criteria for the diagnosis of schizoaffective disorder, manic type, with patients meeting rigorous criteria for manic disorder and schizophrenia, using three methods of validation: family history, short-term treatment response, and long-term outcome. No significant differences were found between patients with manic disorder and schizoaffective disorder. However, consistent and often highly significant differences separated patients with schizophrenia from those with manic disorder and schizoaffective disorder. The findings suggest that schizoaffective disorder, as currently defined, is not a valid and independent entity. The authors suggest that psychotic disorders not diagnosable as manic-depressive illness or schizophrenia and without apparent organic basis would best be called "undiagnosed" or "atypical" psychosis. Further, while proposals for new diagnoses or for subtyping of schizophrenia or manic-depressive illness should be encouraged, these should undergo rigorous screening for validity before being accepted into clinical use.     

Antisocial personality disorder and anxiety disorder: A diagnostic variant?

Antisocial personality disorder (ASPD) with co-morbid anxiety disorder may be a variant of ASPD with different etiology and treatment requirements. We investigated diagnostic co-morbidity, ASPD criteria, and anxiety/affective symptoms of ASPD/anxiety disorder. Weighted analyses were carried out using survey data from a representative British household sample. ASPD/anxiety disorder demonstrated differing patterns of antisocial criteria, co-morbidity with clinical syndromes, psychotic symptoms, and other personality disorders compared to ASPD alone. ASPD criteria demonstrated specific associations with CIS-R scores of anxiety and affective symptoms. Findings suggest ASPD/anxiety disorder is a variant of ASPD, determined by symptoms of anxiety. Although co-morbid anxiety and affective symptoms are the same as in anxiety disorder alone, associations with psychotic symptoms require further investigation.     

Social phobia and avoidant personality disorder: one spectrum disorder?

General population data was used to examine if empirically derived subtypes of social phobia with and without avoidant personality disorder (APD) could be differentiated on self-report measures of anxiety severity, level of global functioning and the number of fulfilled diagnostic criteria for other personality disorders. DSM-IV diagnoses of social phobia, APD and indices of other personality disorders were determined by means of a postal survey. The presence of APD was associated with compromised functional status and a higher frequency of fulfilled diagnostic criteria for additional personality disorders. However, APD did not modify the effect of social phobia subtypes on anxiety severity, level of global functioning or number of personality disorder indices. The presence of comorbid APD in social phobics seems to predict a global functioning decrement independent of anxiety severity. The results imply that social phobia and APD may represent different points on a severity continuum rather than easily defined discreet categories suggesting that social phobia and APD may represent a spectrum of anxiety symptoms related to social anxiety.     

Bipolar disorder with late onset: an organic variety of mood disorder?

Bipolar disorder (BD) is commonly associated with late adolescence or early adulthood, although a substantial proportion of patients develops the condition in later life. The results of early clinical investigations suggested that cases of bipolar disorder with onset in later life were more often associated with 'organic causes', and could potentially justify the distinction between early and late onset bipolar disorder. This paper reviews currently available evidence in support of the organic hypothesis for late onset bipolar disorder. It concludes that the split of bipolar disorder according to age at onset is artificial, and lacks clinical significance and epidemiological support.     

Is borderline personality disorder part of the bipolar spectrum?

In recent years, advances in the areas of both bipolar and borderline personality disorders have generated considerable interest in the clinical interface between these two conditions. Developments in the study of the neurobiology of borderline personality disorder suggest that many patients with this diagnosis have etiological features in common with those diagnosed with bipolar disorders. This claim is supported by new insights into the phenomenology of both disorders and by evidence that mood stabilizers are efficacious in the pharmacological management of borderline patients. This area of research is an important one because of the considerable morbidity and public health costs associated with borderline personality disorder. Since borderline patients can be so challenging to care for, it may be that a reframing of the disorder as belonging to the broad clinical spectrum of bipolar disorders holds benefits for patients and clinicians alike.     

Executive deficits: A continuum schizophrenia–bipolar disorder or specific to schizophrenia?

Executive dysfunction is a core deficit in schizophrenia (SCH). However, some controversy exists when examining such deficits in studies of bipolar disorder (BD). The aim of the present research was to investigate whether executive deficits were similar or distinct in both illnesses. 148 patients with BD, 262 patients with stable SCH and 108 healthy controls (CT) were recruited for the study. The BD patients were also differentiated according to the clinical subtype (BD subtype I, BDI, or subtype II, BDII) they exhibited and according to whether there was a previous history of psychosis. All subjects completed a broad neuropsychological battery. The influences of other clinical data were also evaluated. Both the BD and SCH patients showed widespread deficits in all executive tasks, with no differences between these two groups of patients. BDII patients only showed some selective deficits, and their scores on planning and inhibitory tasks fell on the continuum between the CT, the BDI and the SCH patients. Psychotic phenotypes did not influence the BD patients' performance on the battery. Other clinical variables related to illness severity did influence deficits in any subgroup of patients. Our results point to the existence of common executive disturbances in both diagnostic categories. Moreover, the inclusion of subclinical phenotypes in research may be helpful in cognitive assessment studies.     

Impulsive personality traits in male pedophiles versus healthy controls: is pedophilia an impulsive-aggressive disorder?

Pedophilia is characterized by sexual attraction to prepubescent children. Despite the extensive literature documenting the pervasive and pernicious effects of childhood sexual abuse, there is surprisingly little psychiatric literature on pedophilia and its etiology remains enigmatic. In recent years, the psychiatric literature on the phenomenology, neurobiology, and treatment of impulsive-aggressive disorders has grown significantly. As some investigators have conceptualized pedophilia as an impulsive-aggressive disorder, it is of interest whether recent advances in the study of impulsive-aggressive disorders might shed light on pathological mechanisms underlying pedophilia. In the following study, 20 male subjects with a DSM-IV diagnosis of pedophilia, heterosexual type were recruited from an outpatient facility for sexual offenders and compared to 24 demographically similar control subjects. Groups were compared on three personality instruments--the Millon Clinical Multiaxial Inventory-II (MCMI-II), the Temperament and Character Inventory (TCI), and the Dimensional Assessment of Personality Impairment-Questionnaire (DAPI-Q)--to assess for select impairment in impulsive-aggressive personality traits. Pedophiles showed severe and pervasive personality impairment relative to controls. Although there was evidence of impulsivity, the findings do not suggest a predominance of impulsive-aggressive traits, and in fact provide evidence of inhibition, passive-aggression, and harm avoidance. The notion of "compulsive-aggression" in pedophilia is proposed.     

"Gamma synchrony" in first-episode schizophrenia: a disorder of temporal connectivity?

OBJECTIVE: There has been a convergence of models describing schizophrenia as a disconnection syndrome, with a focus on the temporal connectivity of neural activity. Synchronous gamma-band (40-Hz) activity has been implicated as a candidate mechanism for the binding of distributed neural activity. To the authors' knowledge, this is the first study to investigate "gamma synchrony" in first-episode schizophrenia. METHOD: Forty medicated first-episode schizophrenia patients and 40 age- and sex-matched healthy comparison subjects participated in a conventional auditory oddball paradigm. Gamma synchrony, time-locked to target stimuli, was extracted from an ongoing EEG. The magnitude and latency of both early (gamma 1: -150 msec to 150 msec poststimulus) and late (gamma 2: 200 to 550 msec poststimulus) synchrony were analyzed with multiple analysis of variance. RESULTS: First-episode schizophrenia patients showed a decreased magnitude and delayed latency for global gamma 1 synchrony in relation to healthy comparison subjects. By contrast, there were no group differences in gamma 2 synchrony. CONCLUSIONS: These findings suggest that first-episode schizophrenia patients have a global decrease and delay of temporal connectivity of neural activity in early sensory response to task-relevant stimuli. This is consistent with cognitive evidence of perceptual integration deficits in this disorder and raises the possibility that a breakdown in the early synchrony of distributed neural networks is a marker for the onset of schizophrenia.     

Does the Schizotypal Personality Questionnaire reflect the biological-genetic vulnerability to schizophrenia?

We investigated whether the Schizotypal Personality Questionnaire (SPQ) [Schizophr. Bull. 17 (1991) 555.] could be an indicator of the biological-genetic vulnerability to schizophrenia. We hypothesized that the mean scores on three dimensions of the SPQ of different groups of relatives of patients with schizophrenia would parallel their risk for developing schizophrenia. The SPQ was administered to 51 first-episode schizophrenia patients, 63 parents of schizophrenia patients, 42 siblings of schizophrenia patients and 12 children of schizophrenia patients. Patients differed from the relatives on all three dimensions. Siblings and children scored significantly higher than parents on Positive Schizotypy, and the insignificant difference between the siblings and children was in the expected direction. The results could not be explained by the differences in age, sex, IQ or substance abuse. No differences were found for Disorganization Schizotypy between the relatives. Children scored higher than parents on Negative Schizotypy. The current study offers support to the hypothesis that the positive dimension of SPQ reflects the genetic vulnerability to schizophrenia.