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M F Lenzenweger

Publications and source records attributed to M F Lenzenweger.

At least 37 records · Page 2Linked to original sources
PubMed1992

Empirical assessment of the factorial structure of clinical symptoms in schizophrenic patients: formal thought disorder.

Male schizophrenic patients (n = 142) were examined with a clinical assessment of their language dysfunctions with the Scale for the Assessment of Thought, Language, and Communication (TLC). Confirmatory factor analyses were conducted to test the relative fit of several differential theoretical models of the factorial structure of thought disorders. The models examined were positive-negative thought disorder, a three-factor model based on the results of an earlier exploratory factor analysis, and a simpler verbal productivity-disconnection model that can be extracted from other exploratory analyses and empirical studies. The positive-negative thought disorder model failed to fit the data, while the three-factor model fit the data, but no better than the simpler verbal productivity-disconnection model.

Adult↗
PubMed1992

Empirical assessment of the factorial structure of clinical symptoms in schizophrenia: negative symptoms.

The factor structure of the Scale for the Assessment of Negative Symptoms (SANS) was examined in a confirmatory factor analysis that used the LISREL procedure. Four models of negative symptom factors were tested in 130 hospitalized schizophrenic patients. A three-factor model of diminished expression, social dysfunction, and disorganization generated by the authors yielded a superior fit to the data relative to the two-factor model of Liddle (1987b) and a unifactorial severity model. A four-factor model based on the original subscale formulation of the SANS failed to fit the data.

Adult↗
PubMed1992

Confirming the latent structure and base rate of schizotypy: a taxometric analysis.

Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl & Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973; Meehl & Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; Chapman, Chapman, & Raulin, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical university sample (N = 1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10.

Adult↗
PubMed1991

Trait-state artifacts and the diagnosis of personality disorders.

The multiaxial nature of DSM-III has stimulated interest in the personality disorders. There are also indications that it has produced an increase in their diagnosis. However, there is clinical and psychometric evidence that a personality evaluation undertaken while a patient is in a dysphoric mental state may distort or misrepresent traits, the so-called trait-state problem in personality assessment. The present study appears to be the first to investigate this phenomenon with a clinical interview rather than with personality tests. It examined the effect of anxiety, depression, and level of global impairment on the diagnosis of personality disorder and the assessment of the criteria for the individual Axis II disorders. Eighty-four patients, most of whom had current Axis I diagnoses, were evaluated by seven experienced clinicians with a new semistructured interview, the Personality Disorder Examination. The sample evidenced a trend toward acknowledging fewer maladaptive personality traits at follow-up than at entry. There was no evidence, however, that anxiety or depression had affected either the diagnosis of a personality disorder or the criteria associated with most of the individual personality disorders.

Adolescent↗
PubMed1991

Confirming schizotypic personality configurations in hypothetically psychosis-prone university students.

The personality features of hypothetically psychosis-prone (or schizotypic) subjects were examined. Schizotypic (n = 32) and control (n = 44) subjects were identified within a pool of 726 randomly ascertained nonclinical university students who had completed the Perceptual Aberration Scale (PAS) during a large-scale screening study. Approximately 4-6 months after the initial screening, the schizotypic and control subjects completed the Minnesota Multiphasic Personality Inventory (MMPI). Schizotypic subjects as a group displayed an average MMPI profile consistent with schizotypic personality features, whereas the control subjects did not. Moreover, multivariate profile analysis revealed that the schizotypic group MMPI profile differed significantly in shape from the control group profile. Finally, schizophrenia-related MMPI high-point codes were five times as prevalent among the PAS-identified schizotypic subjects as among the controls. The results suggest that the PAS identifies individuals who show schizotypic personality MMPI configurations and may carry a latent vulnerability for schizophrenia or, more broadly, psychosis.

Adult↗
PubMed1991

Schizotypy and sustained attention.

We examined sustained attention in 32 schizotypic and 43 normal control subjects from a large, randomly ascertained nonclinical university population. Schizotypy status was determined with the Perceptual Aberration Scale. Sustained attention was measured with the Continuous Performance Test-Identical Pairs. Schizotypic subjects displayed significantly poorer sustained-attention performance than did control subjects, as measured by d and overall hit rate. Although schizotypic subjects evidenced greater levels of anxiety and depression, sustained-attention performance was not significantly associated with these mental state factors. Our results provide evidence for a subtle sustained-attention deficit among schizotypes and are interpreted in light of previous attention research with actual schizophrenic patients as well as children at risk for schizophrenia. Utility of the psychometric high-risk strategy in psychopathology research is discussed.

Adolescent↗
PubMed1991

Examining the underlying structure of schizophrenic phenomenology: evidence for a three-process model.

The present report examined the latent structure of schizophrenic phenomenology. Schizophrenic patient case histories (n = 192) were rated for positive symptoms, negative symptoms, and premorbid social adjustment and the observed covariation among these clinical features was evaluated using a model-based confirmatory factor analytic approach. Our results indicated that schizophrenic phenomenology was best characterized by three distinct underlying structures. These data provide empirical support for Strauss et al.'s (1974) three-process model, which suggests that positive symptoms, negative symptoms, and disordered premorbid personal-social relationships are three distinct classes of phenomenology possibly reflective of three relatively independent pathological processes in schizophrenia. The data are also consistent with Crow's (1980, 1985, 1987) model of schizophrenic symptomatology, differentiating social impairment from both positive and negative symptoms. The heuristic implications of these data for the development of schizophrenia are discussed and the utility of a replication of the present study is noted.

Adult↗
PubMed1990

Discerning the latent structure of hypothetical psychosis proneness through admixture analysis.

The application of psychometric procedures to a normal population sample to detect individuals with increased liability for schizophrenia is a useful methodological adjunct to the traditional genetic high-risk strategy. A necessary and reasonable step in the process of establishing the utility of a viable psychometric index of schizotypy is the formal investigation of the latent structure of psychometric values. The present study used admixture analysis to examine the distribution of scores on the Perceptual Aberration Scale (PAS), an objective measure of hypothetical psychosis-proneness, in a randomly ascertained sample of 18-year-old university students (n = 707). We applied parametric methods that assumed normally distributed component distributions; viewed in this context, our results are hypothesis-generating and not definitive confirmation of specific hypotheses. Within our methodological framework, the results provide strong evidence for the commingling of normal distributions, even after allowing for unequal variances across components and after removing skewness. The overall distribution of power-transformed data is consistent with the existence of three qualitatively distinct classes of PAS responders. We discuss our results in light of Meehl's model of schizotaxia, a "mixed model" of inheritance of liability to schizophrenia, and we review the methodological implications of our findings for future research.

Adolescent↗
PubMed1989

Detection of familial schizophrenia using a psychometric measure of schizotypy.

This study examined the lifetime expectancy (morbid risk) of schizophrenia, unipolar depression, and bipolar disorder in the first-degree relatives of 101 nonpsychotic psychiatric patients (probands) who were classified as schizotypy-positive or schizotypy-negative using a psychometric measure of schizotypy, the Perceptual Aberration Scale. The relatives of schizotypy-positive probands were significantly more likely to have been treated for schizophrenia than the relatives of schizotypy-negative probands. Morbid risk for unipolar depression or bipolar disorder among first-degree relatives did not differ between the proband groups. The results support Meehl's theory of the pathogenesis of schizophrenia and enhance the construct validity of the Perceptual Aberration Scale. The heuristic potential of a psychometric high-risk strategy in schizophrenia research is discussed and the need for replication of the present study is emphasized.

Adult↗
PubMed1989

The continuous performance test, identical pairs version: II. Contrasting attentional profiles in schizophrenic and depressed patients.

The Continuous Performance Test-Identical Pairs version was administered to 14 schizophrenic patients, 17 depressed patients, and 28 normal controls. The task was divided into verbal and spatial stimuli, as well as no-distraction and distraction (verbal and auditory) conditions. Both patient groups displayed attentional impairments compared to normal subjects, but they differed from each other in specific profiles. Schizophrenic patients were characterized by a global impairment and a particular inability to focus on the critical stimuli, whether verbal or spatial. They also made an excess of random responses throughout the task but showed no evidence that attention declined from its initial level over time. Depressed patients did not display a global attentional deficit but did show a specific inability to attend to spatial as compared to verbal stimuli and, in particular, a confusion when the spatial stimuli were only slightly different. Performance on a secondary task in response to a change in expectation improved dramatically for depressed but not schizophrenic patients, suggesting a more efficient allocation strategy, a greater reserve of processing capacity, or more dependence on motivational factors in depressed patients. Schizophrenic and depressed patients were alike in extent of distractibility. Whereas normal controls improved with the onset of external distraction, schizophrenic and depressed patients deteriorated to an equal extent. Distractibility was thus concluded to be a correlate of acute psychiatric illness and not specific for schizophrenia.

Adult↗
PubMed1989

Psychosis proneness and clinical psychopathology: examination of the correlates of schizotypy.

The present report examined the associations between the Perceptual Aberration Scale (PAS), a prominent psychometric index of hypothetical psychosis proneness, and several measures of clinical psychopathology in a nonpsychotic psychiatric sample (N = 101). Patients were examined by experienced clinicians using structured psychiatric interviews to assess DSM-III-R Axis I and II conditions and rated for anxiety, depression, severity of illness, and current adult social competence. Elevated scores on the PAS were most closely associated with anxiety and depression as well as schizotypal, schizoid, avoidant, and obsessive-compulsive personality disorder symptomatology. Hierarchical regression analysis identified schizotypal symptoms and anxiety as the two underlying psychopathological processes most useful in explaining variance in PAS scores. Results are interpreted as supporting both the clinical relevance and research utility of the PAS and enhancing the construct validity of Meehl's model of schizotypy.

Adolescent↗
PubMed1989

Models of positive and negative symptoms in schizophrenia: an empirical evaluation of latent structures.

The present investigation empirically evaluated three competing models of the relations between positive and negative symptoms in schizophrenia, namely the severity-liability model (Gottesman, McGuffin, & Farmer, 1987), Andreasen's unidimensional bipolar model (Andreasen & Olsen, 1982), and Crow's independent dual-process model (Crow, 1980a, 1980b). Using positive and negative symptom ratings based on 220 schizophrenic subjects, the results of a LISREL VI (Joreskog & Sorbom, 1984) confirmatory factor analysis revealed that Crow's model of positive and negative symptoms provided the best fit to the observed data among the three models. The severity-liability model provided a modest fit to observed data, and Andreasen's model fit the data poorly. Results are interpreted as supporting the validity of the positive and negative symptom distinction in schizophrenia and as providing substantive empirical support for Crow's independent dual-process model. The methodological advantages of confirmatory factor analysis in the specification and evaluation of theoretical models in experimental and developmental psychopathology are discussed.

Diseases in Twins↗
PubMed1988

A multidimensional approach to the genetics of schizophrenia.

To determine which dimensions of psychopathology are associated with a greater liability to develop schizophrenia, the authors examined the case histories of 151 monozygotic probands from five twin studies. Proband twins from pairs concordant for schizophrenia had greater numbers of negative symptoms, poorer premorbid adjustment, fewer paranoid symptoms, and earlier ages at onset than probands from discordant pairs. In discriminant analyses, negative symptoms, premorbid social competence, and paranoid symptoms each contributed to the discrimination between concordant and discordant pairs. These results provide support for Strauss et al.'s suggestion that these three types of symptoms reflect three different functional processes in the development of schizophrenia.

Adult↗
PubMed1985

Positive and negative schizophrenic symptoms, attention, and information processing.

This study was concerned with the relationship between attentional and information-processing deficits and positive vs. negative symptoms in schizophrenia. Sixteen schizophrenic patients, rated for extent of positive and negative symptomatology, 17 depressed patients, and 31 normal control subjects were tested on a measure of distractibility and ability to process under information overload. To establish the validity of our measures, schizophrenic patients were compared with depressed patients and with normal control subjects. Lowered processing capacity appeared to be specific to schizophrenia, although the specificity of differential distractibility was less clear. For schizophrenic patients, positive symptoms were related to distractibility, whereas negative symptoms were associated with lowered processing capacity. These findings were interpreted as supporting Crow's (1981) hypothesis that the two clinical syndromes reflect independent pathological processes.

Adult↗
PubMed1984

Symptoms and the genetics of schizophrenia: implications for diagnosis.

To determine whether genetic influences in schizophrenia are related to the symptoms specified by diagnostic criteria, the case histories of 151 pairs of monozygotic twins from five twin studies of schizophrenia were rated for positive and negative symptoms. Concordance rates in monozygotic twins were significantly higher when probands had a greater number of negative symptoms; no evidence of a similar relationship was found for positive symptoms. The data indicate that negative symptoms may be characteristic of schizophrenia in which there is a greater genetic component. The results have important implications for determining diagnostic criteria and understanding the pathogenesis of schizophrenia.

Diseases in Twins↗