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R Toomey

Publications and source records attributed to R Toomey.

At least 19 recordsLinked to original sources
PubMed1999

Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: a 4-year follow-up study.

In a prior study of 54 relatives of patients with schizophrenia and 72 control participants, 3 neuropsychological functions met the criteria for risk indicators of the schizophrenia genotype: executive functioning, memory, and auditory attention. In an assessment of the stability of these findings, the sample was reexamined 4 years after the initial assessment. Three test scores were found to differ between groups (Immediate Verbal Memory, Delayed Verbal Memory, and Dichotic Listening Digits Detected) or to show a significant Group x Gender interaction (immediate and delayed verbal and visual memories). None of the test scores showed Group x Time interactions, suggesting that the discriminating power of the tests was stable over time. Evidence for deficits in working memory and rule learning on the object alternation test was also found. These results support the idea that neuropsychological dysfunction among relatives of patients with schizophrenia is a stable trait caused by the familial predisposition to schizophrenia.

Adult↗
PubMed1998

Sex differences in self-reported schizotypal traits in relatives of schizophrenic probands.

We used the Schizotypal Personality Questionnaire to evaluate schizotypal traits in 44 normal volunteers and 40 non-psychotic, biological relatives of schizophrenic probands. Relatives endorsed more cognitive-perceptual traits than did controls; a group-by-sex interaction indicated that male relatives accounted for this difference. Although not statistically significant, a similar pattern was observed for interpersonal traits. Thus, elevated rates of some schizotypal traits appear to be more prominent in male than in female relatives of schizophrenic probands, at least when assessed by self-report. Subscale analysis indicated that differences were accounted for primarily by suspiciousness and ideas of reference, suggesting that paranoid-like phenomena from both the cognitive-perceptual and interpersonal factors may constitute an important dimension of schizotypy in relatives. Unlike previous studies, we did not find any differences in constricted affect or disorganization signs. Interviews and other non-self-report techniques are probably best suited for an assessment of these features, although the question remains as to whether the combination of both approaches might provide some incremental discriminatory power.

Adult↗
PubMed1998

Association of neuropsychological vulnerability markers in relatives of schizophrenic patients.

We investigated the association of neuropsychological risk indicators in a matched sample of first-degree relatives of schizophrenic patients (n = 54) and normal controls (n = 72). We focussed on three functions previously identified in a smaller, initial sample as putative risk indicators of the schizophrenia genotype: abstraction, verbal memory and auditory attention. The expanded sample of relatives displayed significantly lower scores than controls on abstraction, verbal memory and auditory attention. The relatives demonstrated significant intercorrelations among these three functions. The significant correlations among relatives between attention and verbal memory and between attention and abstraction differed significantly from these correlations among controls. We discuss how the use of multiple risk indicators may help us better identify those relatives that carry the schizophrenia genotype.

Adult↗
PubMed1998

Co-occurrence of abuse of different drugs in men: the role of drug-specific and shared vulnerabilities.

BACKGROUND: Previous research has demonstrated genetic and environmental influences on abuse of individual substances, but there is less known about how these factors may influence the co-occurrence of abuse of different illicit drugs. METHODS: We studied 3372 male twin pairs from the Vietnam Era Twin Registry. They were interviewed using the Diagnostic Interview Schedule, Version III, Revised to investigate the extent to which the abuse of different categories of drugs occurs together within an individual, as well as the possibility that genetic and environmental factors are responsible for observed co-occurrence. Co-occurrence was quantified using odds ratios and conditional probabilities. Multivariate biometrical modeling analyses were used to assess genetic and environmental influences on co-occurrence. RESULTS: Abusing any category of drug was associated with a marked increase in the probability of abusing every other category of drugs. We found evidence for a shared or common vulnerability factor that underlies the abuse of marijuana, sedatives, stimulants, heroin or opiates, and psychedelics. This shared vulnerability is influenced by genetic, family environmental, and nonfamily environmental factors, but not every drug is influenced to the same extent by the shared vulnerability factor. Marijuana, more than other drugs, was influenced by family environmental factors. Each category of drug, except psychedelics, had genetic influences unique to itself (ie, not shared with other drug categories). Heroin had larger genetic influences unique to itself than did any other drug. CONCLUSION: There are genetically and environmentally determined characteristics that comprise a shared or common vulnerability to abuse a range of illicit drugs.

Adult↗
PubMed1998

A registry-based twin study of depression in men.

BACKGROUND: The only large, registry-based twin study of depression using diagnostic criteria assessed by structured interview included only women. We present results from a comparable study of men. METHODS: Data were collected using a standardized telephone interview of men from the Vietnam Era Twin Registry. Both twins from 3372 pairs participated. Proband-wise concordance rates and biometric modeling were used to analyze the data. RESULTS: The diagnosis of major depression (MD), as defined by DSM-III-R, and the subtype of severe/psychotic MD were significantly affected by genetic (h2=0.36 and 0.39, respectively) and nonshared environmental (e2=0.64 and 0.61, respectively) factors but not by family environmental factors. Dysthymia and mild and moderate MD were affected by family environmental (c2=0.27, 0.08, and 0.14, respectively) and nonshared environmental (e2=0.73, 0.92, and 0.86, respectively) factors but not by genetic factors. Early-onset (before age 30 years) and late-onset (after age 30 years) MD were significantly affected by genetic (h2=0.47 and 0.10, respectively) and nonshared environmental (e2=0.53 and 0.90, respectively) factors. Early-onset MD was significantly more heritable than late-onset MD. CONCLUSIONS: The magnitude of genetic and environmental effects on depression in men is similar to that previously reported in women. Also similar to previous findings, more severe and earlier-onset depression may be more strongly affected by genetic factors, but differences in the reliability of reports of depression associated with severity may inflate estimates of the effect of the unique environment and deflate heritability estimates for less severe depression.

Adult↗
PubMed1998

Negative, positive, and disorganized symptom dimensions in schizophrenia, major depression, and bipolar disorder.

We compared the factor structure of positive and negative symptoms in schizophrenia (N = 214), major depression (N = 97), and bipolar disorder (N = 58) to determine whether schizophrenia factors would generalize to mood disorders. A study of schizophrenia and mood disorders identified patients whose symptoms were evaluated with the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. We conducted principal component analyses with orthogonal rotation on the global ratings. The factor structure replicated earlier findings of three factors (negative, positive, and disorganization) in groups with schizophrenia, combined mood disorders, and psychotic symptoms, regardless of diagnosis. An additional negative symptom factor was found in the major depression group. The bipolar group did not have a disorganization factor. Similar symptom factors in schizophrenia and mood disorders suggest a continuity in the major affective and psychotic disorders that appears to reflect the underlying dimension of a psychotic process.

Adult↗
PubMed1997

Sex differences in neuropsychological function in non-psychotic relatives of schizophrenic probands.

Some recent studies suggest that men with schizophrenia may have greater neuropsychological deficits than women. It is not known, however, whether similar sex differences may be present in biological relatives of schizophrenic patients. We evaluated neuropsychological functioning of 54 relatives of schizophrenic patients and 72 normal volunteers. It was hypothesized that, if sex differences were present, they would be accounted for largely by deficits in male relatives. We were particularly interested in three neuropsychological functions that we previously identified as putative neuropsychological vulnerability indicators for schizophrenia: (1) abstraction/executive function; (2) verbal memory; and (3) auditory attention. There were significant group x sex interactions for verbal memory and motor function, and trends toward significant interactions for auditory attention and mental control/encoding. However, with the exception of motor function, it was the female relatives who accounted for most of the impairment. A speculative explanation for the findings is that women may have a higher threshold than men for developing schizophrenia. If so, female relatives might be able to withstand greater impairments than men before developing psychotic symptoms. Consequently, in a sample that was limited to non-psychotic relatives--as in the present study--there could be over-representation of both less impaired men and more impaired women. Alternative explanations and limitations of the study are also discussed.

Adolescent↗
PubMed1997

Social processing correlates of nonverbal social perception in schizophrenia.

This study examines the relationship of nonverbal social perception to other areas of social functioning in schizophrenia. One model of interpersonal problem-solving skills presents a sequence of receiving, processing, and sending skills. Social perception skills best fit the first stage in this model: receiving skills. As expected, schizophrenic subjects (N = 29) were less skillful than normal subjects (N = 15) on measures of social problem solving, understanding of social sequences, and social judgment. In addition, performance on these tasks was significantly related to nonverbal social perception, but only for the schizophrenic group. Thus, deficits in nonverbal social perception are related to other measures of social functioning in schizophrenia. Implications of these findings for understanding and treating social deficits in schizophrenia are discussed.

Adult↗
PubMed1997

Revisiting the factor structure for positive and negative symptoms: evidence from a large heterogeneous group of psychiatric patients.

OBJECTIVE: The factor structures of individual positive and negative symptoms as well as global ratings were examined in a diagnostically heterogeneous group of subjects. METHOD: Subjects were identified through a clinical and family study of patients with major psychoses at a VA medical center and evaluated with the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. For the examination of global-level factor structures (N = 630), both principal-component analysis and factor analysis with orthogonal rotation were used. Factor analysis was used for the examination of item-level factor structures as well (N = 549). RESULTS: The principal-component analysis of global ratings revealed three factors: negative symptoms, positive symptoms, and disorganization. The factor analysis of global ratings revealed a negative symptom factor and a positive symptom factor. The item-level factor analysis revealed two negative symptom factors (diminished expression and disordered relating), two positive symptom factors (bizarre delusions and auditory hallucinations), and a disorganization factor. CONCLUSIONS: The generation of additional meaningful factors at the item level suggests that important information about symptoms is lost when only global ratings are viewed. Future work should explore clinical and pathological correlates of the more differentiated item-level symptom dimensions.

Adult↗
PubMed1997

How do genes influence marijuana use? The role of subjective effects.

This study investigated determinants of the subjective effects of marijuana and the relationship of subjective effects to marijuana use. Subjects were 8169 twins drawn from the Vietnam Era Twin Registry. Subjects who used marijuana more than five times (n = 2513) reported whether they experienced each of 23 subjective reactions. Factor analysis identified a positive (pleasant) reaction factor and a negative (unpleasant) reaction factor. Both factors were related to duration and frequency of use. Pairs in which both members used marijuana more than five times (MZ = 352 pairs; DZ = 255 pairs) were examined to assess determinants of subjective effects. Approximately one-quarter of the variance in each factor was determined by additive genetic influences; the remaining variance was determined by environmental factors that are not shared by members of a twin pair. The shared or family environment had no detectable influence on either subjective reaction factor.

Adult↗
PubMed1996

Genetic influences on DSM-III-R drug abuse and dependence: a study of 3,372 twin pairs.

Research and clinical experience indicate that drug use disorders tend to run in families. The objective of this study was to distinguish between the family environment and genetic factors as the source of this observed family resemblance. Data were collected by telephone interview from members of the Vietnam Era Twin Registry, comprising male twin pairs who served in the U.S. military between 1965 and 1975. There were 3,372 pairs in which both twins participated. Drug use disorder was defined as receiving a diagnosis of drug abuse or dependence according to DSM-III-R; 10.1% of the sample had abused or been dependent on at least one illicit drug. A significant difference between concordance rates for monozygotic (26.2%) vs. dizygotic (16.5%) twins indicated a genetic influence on drug use disorder. Biometrical modeling indicated that genetic factors (34% of the variance), the environment shared by twins (28% of the variance), and the nonshared environment (38% of the variance) had significant influences of similar magnitudes on the individual's risk of developing a drug use disorder. These results support the application of molecular genetic approaches to elucidate the genetic influence on drug use disorder, as well as the potential efficacy of environmental intervention to reduce risk.

Adult↗
PubMed1996

Construct validity of two tests of social cognition in schizophrenia.

The construct validity was examined of two measures of social cognition in schizophrenia: (1) a measure of differential deficit in concrete versus abstract social cue perception and (2) a measure of differential deficit in concrete versus abstract situational feature recognition. A significant relationship between the two difference scores would be expected if both measured differential cognition of abstract and concrete social information. This correlation would be expected to remain significant even after the influence of a generalized deficit in social cognition was partialed out. Twenty-three subjects with DSM-III-R diagnoses of schizophrenia completed a videotaped measure of social cue perception and a pencil-and-paper measure of situational feature recognition. Results showed that standardized residual scores representing the difference in abstract and concrete cue perception and representing the difference in abstract and concrete situational feature recognition were significantly associated. Implications of these strategies for understanding and remediating the social cognitive deficits of schizophrenia are discussed.

Adult↗
PubMed1996

Neuropsychological functioning among the elderly nonpsychotic relatives of schizophrenic patients.

In our prior work with a young sample (age < 60), we showed that three neuropsychological functions were impaired among relatives of schizophrenic patients: abstraction, verbal memory, and auditory attention. In the present work we show that these results do not generalize to an older sample aged 60 years and greater. Thus, although we and others have put forth measures of neuropsychological function as indicators of the schizophrenia genotype, the present study suggests that conclusions may be limited to non-elderly samples. Further work is needed to address this issue definitively.

Aged↗
PubMed1995

Recognition and judgment of facial stimuli in schizotypal subjects.

Affect recognition abilities, an important component of successful social functioning, were examined in two groups of schizotypal subjects who were identified by the Perceptual Aberration/Magical Ideation and Physical Anhedonia Scales (PABS, MIS, PAS). Prior research has demonstrated social impairments in subjects identified by these scales and in schizophrenics. Although research has shown schizophrenic subjects to have facial affect recognition deficits, the present results did not support the hypothesis that such impairments would appear in subjects exhibiting similar symptoms, but to a less severe degree, when compared with controls. The results suggest that deficits in emotional decoding may appear at a relatively late stage in the developmental course of mental disorder, or may only be associated with more severe levels of schizophrenia-spectrum symptomatology. The paper discusses theoretical and methodological implications for research on the components and development of social deficits in the schizophrenia-spectrum disorders.

Adult↗
PubMed1995

Correlates of psychosis proneness in relatives of schizophrenic patients.

The Magical Ideation Scale (MIS), Perceptual Aberration Scale (PABS), Social Anhedonia Scale (SAS), and Physical Anhedonia Scale (PAS) were administered to 98 relatives of schizophrenic patients along with a measure of personality disorders (the Personality Diagnostic Questionnaire--Revised). Hierarchical regression analysis indicated that the schizotypal and borderline personality disorder (PD) scales explained significant variance in both the MIS and PABS; the avoidant PD scale also explained significant variance in the PABS. The schizoid, paranoid, and avoidant PD scales explained significant variance in the SAS. Sibling intraclass correlations indicated a significant heritability of 0.62 for the PABS.

Adult↗
PubMed1995

Interpersonal problem solving and information processing in schizophrenia.

Cognitive models of interpersonal problem solving have been proposed for, but infrequently tested on, samples of schizophrenia subjects. This study undertook to examine the relationships between the receiving, processing, and sending skills that comprise one model of interpersonal problem solving with information processing and social cue perception. Twenty-six patients with a DSM-III-R diagnosis of schizophrenia or schizoaffective disorder completed measures of interpersonal problem solving, social cue perception, visual vigilance, verbal memory, conceptual flexibility, and psychiatric symptoms. Significant and robust relationships were found between sensitivity to social cues and receiving, processing, and sending skills. Only recognition and recall memory, of the various other information-processing measures, were found to be related to any of the three problem-solving skills. Associations between problem solving and cognitive deficits did not seem to be attributable to psychiatric symptoms. Implications of these findings for understanding and remediating the problem-solving deficits of schizophrenia patients are discussed.

Adult↗
PubMed1994

Comparison of schizotypal relatives of schizophrenic versus affective probands.

In order to investigate possible heterogeneity in schizotypal personality disorder (SPD), two groups of schizotypals, one related to schizophrenic probands (FSPD) (n = 34) and one related to affective disorder probands (NFSPD) (n = 14), ascertained in the same family study, were compared. The FSPD group had more inadequate rapport; the groups did not differ in the frequency of any other symptoms of SPD. NFSPDs had higher rates of comorbid histrionic PD and a trend for higher rates of impulsive/dramatic cluster PDs. FSPDs had a trend for higher rates of anxiety disorders. There was a higher risk of bipolar disorder in the relatives of NFSPDs and higher risk for anxiety disorders in the relatives of FSPDs. The relatives of NFSPDs had higher rates for histrionic, narcissistic, and atypical PDs and for having at least one PD.

Adult↗