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Biomedical subjects

R L Morrison

Publications and source records attributed to R L Morrison.

At least 19 recordsLinked to original sources
PubMed1995

Family interactions of schizophrenic and schizoaffective patients: determinants of relatives' negativity.

Videotaped family problem-solving interactions of 57 schizophrenic or schizoaffective patients and their relatives were examined for predictors of negativity of their communication behavior. Ratings of patients' behaviors and independent assessments of patients' symptomatology were used to predict the negativity of relatives in the videotaped interaction. The results indicated that severity of symptomatology was not related to relatives' negativity. Patients' social skill, as independently assessed by a role-play test, also was not associated with relatives' negativity. The regression results suggest that with both members of a patient-relative dyad, the quality of communication in a discussion is related to the other participant's level of negativity.

Adolescent↗
PubMed1995

A transmission electron microscopic (TEM) method for determining structural colors reflected by lizard iridophores.

Iridescent tissue colors are thought to be produced by iridophores through the optical phenomenon of thin-layer interference. Land and others have shown that structural features, predominantly reflecting platelet width and the cytoplasmic spacing between layers of platelets, determine the wavelength of light maximally reflected by this mechanism in iridophores. Some researchers have used interference microscopy to estimate these structural parameters, but the most direct measurement technique should be transmission electron microscopy (TEM). Transmission electron microscopy (TEM) has associated processing artifacts (particularly cytoplasmic shrinkage) that preclude direct measurement of ultrastructure, but if a number of assumptions are made, reflected wavelengths can be predicted. A thin-layer interference model and its associated assumptions were tested using TEM measurements of iridophores from several brightly colored tissues of each of three lizards (Sceloporus jarrovi, S. undulatus erythrocheilus, and S. magister). In all the instances examined when the contribution of the pigments present were accounted for, tissue color corresponded with predicted iridophore reflectances from the model. Finally, if the model and its assumptions are assumed to be correct, the amount of iridophore cytoplasmic shrinkage as a result of TEM processing can be calculated.

Animals↗
PubMed1992

The ability of schizophrenics to perceive and cope with negative affect.

Thirty-four schizophrenic patients in an acute in-patient hospital were compared with 24 in-patients with major affective disorder and 19 non-patient controls on a role-play test of social skills and a test of affect perception. The role-play test consisted of 12 simulated conversations in which the subject was confronted by parents and friends expressing high-EE criticism or non-critical dissatisfaction. Schizophrenic patients lacked assertiveness and social skills in all conditions, but they did not show any differential impairment when presented with high EE. They consistently lied and denied errors rather than responding assertively or apologizing, whether confronted with high-EE or benign criticisms. On the affect perception test, schizophrenic patients consistently underestimated the intensity or negativeness of negative emotions, but they were not deficient in perception of positive emotional displays. The data do not support the hypothesis that schizophrenic patients are poor at dealing with high-EE behaviours, but do indicate that their ability to cope with even mild negative affect is impaired. Possible explanations for this impairment include limited attentional capacity, a neurologically based perceptual deficit, and a self-protective mechanism to reduce or avoid stress.

Adaptation, Psychological↗
PubMed1991

Ultrastructural analysis of iridophore organellogenesis in a lizard, Sceloporus graciosus (Reptilia: Phrynosomatidae).

Transmission electron microscopy (TEM) data from the ultrastructure of lizard skin iridophores (reflective dermal chromatophores) are used to illustrate the organellogenesis of small rectangular reflecting platelets, which are the color-generating components of these cells. During the development of reflecting platelets, crystals are deposited within double-membraned vesicles from electron-dense material located within the vesicles. The crystals are initially small but expanded lengthwise eventually to fill the vesicle that contains them. The inner membrane then tightly surrounds the crystal whereas the outer membrane is much more loosely associated with the inner-membrane-bound crystal. These observations allow discussion of the possible origin of the precursor double-membraned vesicles from endoplasmic reticulum (ER) and Golgi-derived vesicles. A model is proposed that incorporates our findings and other published reports to explain the origin of the precursor double-membraned vesicles via three alternative pathways.

Animals↗
PubMed1991

Prevalence and stability of social skill deficits in schizophrenia.

The prevalence of social skill deficits in schizophrenia was examined by comparing patients assessed over a 1 year period with a group of non-patient controls recruited from the community. Social skills were assessed using a role play test and were considered deficient when they were below the range of the control sample. Approximately 50% of the patients were consistently unskilled over the one year, whereas 11% were consistently skilled. Deficits in specific social skills were relative rare. Consistent deficits were present for only one of six specific skills: 14% of the patients were consistently less appropriate in their conversational turn-taking (Meshing) than the controls. Patients' social skills were relatively stable over time. The implications of these results for the assessment and remediation of social skill impairments in schizophrenia are discussed.

Adolescent↗
PubMed1991

Assessment of enduring deficit and negative symptom subtypes in schizophrenia.

The clinical importance of subtypes based on enduring deficit or negative symptoms was examined in a group of schizophrenic patients who were assessed twice over a 1-year period. Subgroups of patients with high levels of enduring negative or deficit symptoms, based on the Scale for the Assessment of Negative Symptoms and the Quality of Life Scale, had a poorer prognosis and were consistently worse in social adjustment, quality of life, and thought disorder over the year than were patients with less severe negative symptoms. Subtypes based on Andreasen's negative schizophrenia classification and on enduring thought disorder were only weakly related to other symptoms and social adjustment. Social-skill deficits were weakly related to the enduring negative symptom subtype and Andreasen's negative schizophrenia. The results suggest that enduring negative and deficit symptoms may be associated with a poor outcome in schizophrenia, including more severe positive symptoms, lower levels of social adjustment, and a poorer quality of life.

Adult↗
PubMed1991

Pigments and ultrastructures of pigment cells in xanthic sailfin mollies (Poecilia latipinna).

Electron micrographs of skin from xanthic (gold) sailfin mollies revealed numerous xanthophores, as well as scattered melanophores. The melanophores were seen to contain premelanosomes in various stages of development. This is consistent with the fact that xanthic mollies have been shown to be tyrosinase positive. Melanosomes in xanthic mollies appear to develop by one of two pathways: 1) from an endoplasmic reticulum-derived vesicle which develops an internal lamellar framework, and 2) by fusion of multiple Golgi-derived vesicles which lack an internal lamellar framework. Analysis of the pigments in the skin of the xanthic mollies identified four colorless pteridine pigments (xanthopterin, isoxanthopterin, neopterin, and pterin) and a carotenoid with an absorbance spectrum similar to beta-carotene. It appears that, unlike some other poeciliid fishes, sailfin mollies do not use pteridine pigments for orange coloration. Rather, they appear to rely primarily on carotenoids.

Animals↗
PubMed1990

Social competence in schizophrenia: premorbid adjustment, social skill, and domains of functioning.

The relations between premorbid adjustment, social skill, and domains of functioning (symptoms, social adjustment) were examined in a group of 107 schizophrenic, schizoaffective, and affective disorder patients. Premorbid sexual adjustment was moderately correlated with social skill in the schizophrenic and schizoaffective patients. Schizophrenic patients had the lowest premorbid adjustment and social skill, followed by schizoaffectives, and then affective patients. Within the schizophrenic group, social skill was significantly related to both current social adjustment and negative symptoms, but not positive symptoms. Similar but weaker effects were found for premorbid adjustment. The results suggest that deficits in social skill are correlated with poor premorbid and morbid social adjustment of schizophrenics.

Adolescent↗
PubMed1990

Gender, social competence, and symptomatology in schizophrenia: a longitudinal analysis.

The relationship between gender and social skill measured by performance on a role play test was examined in a sample of 57 schizophrenics, 33 affective disorder patients, and 20 nonpatient controls. Female schizophrenics were more skilled than male schizophrenics, but no gender differences were present in the affective patients or the controls. Longitudinal analyses conducted on the schizophrenic group indicated that the superior social skill of women was stable over the year following a symptom exacerbation. Symptoms and social adjustment improved for both men and women over the year, but did not differ according to gender. The implications of the results for gender differences in the long-term outcome of schizophrenia are discussed.

Adolescent↗
PubMed1990

Prevalence of substance abuse in schizophrenia: demographic and clinical correlates.

Methodological issues involved in assessing the prevalence of substance abuse in schizophrenia are discussed, and previous research in this area is comprehensively reviewed. Many studies suffer from methodological shortcomings, including the lack of diagnostic rigor, adequate sample sizes, and simultaneous assessment of different types of substance abuse (e.g., stimulants, sedatives). In general, the evidence suggests that the prevalence of substance abuse in schizophrenia is comparable to that in the general population, with the possible exceptions of stimulant and hallucinogen abuse, which may be greater in patients with schizophrenia. Data are presented on the association of substance abuse with demographics, diagnosis, history of illness, and symptoms in 149 recently hospitalized DSM-III-R schizophrenic, schizophreniform, and schizoaffective disorder patients. Demographic characteristics were strong predictors of substance abuse, with gender, age, race, and socioeconomic status being most important. Stimulant abusers tended to have their first hospitalization at an earlier age and were more often diagnosed as having schizophrenia, but did not differ in their symptoms from nonabusers. A history of cannabis abuse was related to fewer symptoms and previous hospitalizations, suggesting that more socially competent patients were prone to cannabis use. The findings show that environmental factors may be important determinants of substance abuse among schizophrenic-spectrum patients and that clinical differences related to abuse vary with different types of drugs.

Adolescent↗
PubMed1990

Positive and negative symptoms in schizophrenia. A cluster-analytic approach.

The relationships between positive and negative symptoms of schizophrenia and between negative symptoms and social dysfunction were investigated using cluster analysis. Clustering across schizophrenic subjects produced three distinct groups, each characterized by some mix of positive and negative symptoms. Clustering across symptoms and behavioral variables produced a cluster comprising negative symptoms and measures of social adjustment and an additional cluster comprising only measures of social skill. A series of correlations revealed a positive relationship between positive and negative symptom measures. chi 2 analysis revealed a significant relationship between the cluster solution across subjects and classification of patients according to negative symptoms based on previously published criteria. Results are discussed in terms of the implications for the further development and refinement of subclassification schemes for schizophrenia.

Adult↗
PubMed1990

Remediation of cognitive deficits in schizophrenia.

Studies have suggested that schizophrenia is characterized by an impairment in the dorsolateral prefrontal cortex that prevents learning of some elementary information processing tasks. To test this hypothesis, the authors administered the Wisconsin Card Sorting Test to 16 schizophrenic inpatients with standard instructions and either contingent or noncontingent reinforcement. Performance was markedly impaired under each condition. A second cohort (N = 12) was tested after receiving instructions plus rehearsal and feedback. These subjects' performance was comparable to nonpatient norms and was maintained on a subsequent day. The results indicate that deficits in performance on the Wisconsin Card Sorting Test are remediable, whether or not they are due to neurological impairment.

Adult↗
PubMed1990

An analysis of social competence in schizophrenia.

Twenty-one schizophrenics with prominent negative symptoms were compared with 37 schizophrenics without them, 33 patients with major affective disorder and 20 non-patient controls on a battery of measures including a role-play test of social skills, the Social Adjustment Scale, and the Quality of Life Scale. The negative schizophrenics were most impaired on every subscale of each measure, followed in order by the non-negative schizophrenics, affective disorder patients, and non-patient controls. The social skill measures were not correlated with positive symptom levels, but were highly correlated with measures of community functioning. The results are consistent with the hypothesis that social dysfunction results from focal deficits in social skills.

Adolescent↗
PubMed1989

Social problem solving in schizophrenia.

The recent literature on social skills training has placed an increasing emphasis on the role of cognitive factors in social failure, as opposed to deficits in motoric skills. It has been hypothesized that schizophrenic patients are markedly deficient in social problem-solving abilities, and several programs have been developed to teach problem-solving skills. Despite high face validity, there is little empirical support for these training programs or the problem-solving model on which they are based. Research on information processing and problem solving in nonpatient populations is discussed, and it is concluded that the model used in these treatment programs is not a good representation of the problem-solving process. In particular, means-ends analysis is not an appropriate strategy for dealing with most interpersonal problems and conflicts. The difficulties experienced by schizophrenic patients in social situations might be due to a number of factors other than deficits in problem-solving skill, including sensitivity to negative affect and disordered communication. It is concluded that further research on problem-solving training programs is clearly warranted but that the validity of the problem-solving model and the utility of the training is uncertain.

Humans↗
PubMed1988

Deficits in facial-affect recognition and schizophrenia.

It has been widely demonstrated that schizophrenic patients show a broad range of deficits in interpersonal skills. Recently, considerable attention has been focused on the ability of these patients to decode affective cues. This article reviews findings about facial-affect recognition in schizophrenia. While the literature on this topic is extensive, many investigations have suffered from significant methodological shortcomings. Strategies to resolve these shortcomings are presented. Possible relationships between problems of affect recognition and other symptoms that characterize schizophrenia are discussed. Neurological mechanisms of facial-affect recognition are reviewed and related to data on lateralized neurological impairment in schizophrenia. Suggestions for future research emphasize careful consideration of affect-recognition deficits in relation to other parameters of schizophrenia.

Affect↗
PubMed1987

Social functioning of schizophrenic patients: clinical and research issues.

Social dysfunction is generally considered an essential feature of schizophrenia. However, despite considerable interest in the social functioning of schizophrenic patients, the precise nature of the social deficits exhibited by these patients remains unspecified. No widely accepted criterion of social competence has been used to investigate their social functioning. Also, social skills researchers have often failed to recognize the heterogeneity of schizophrenia and the impact that this heterogeneity may have on attempts to implement psychosocial interventions. The adverse findings regarding the social behavior of schizophrenic patients are reviewed. Factors relating to schizophrenia that may affect their social functioning are discussed, as are directions for future research that may lead to more effective psychosocial interventions for schizophrenia.

Humans↗