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Biomedical subjects

D K Winstead

Publications and source records attributed to D K Winstead.

At least 19 recordsLinked to original sources
PubMed1992

Deficits in initial feature registration of schizophrenics and substance abusers.

Information processing deficits are consistently reported for schizophrenics. The present study evaluated if the longer duration required by schizophrenics to visually recognize a target may qualify, as proposed by previous studies, as a vulnerability and/or trait biological marker. Critical stimulus duration (CSD) was used as the index of initial target registration and recognition. The CSD is the minimal duration, in ms, to meet task criterion, which in the present study was seven consecutive identifications of the target letter 'T' or 'A'. There were 13 normal controls, 11 methadone maintenance experimental controls, 21 chronic schizophrenics and 12 subacute schizophrenics. Analysis of variance revealed that the CSDs of normal controls and subacute schizophrenics were not statistically different (p > 0.05); the CSDs of chronic schizophrenics were not statistically different from methadone controls (p > 0.05), while the chronic schizophrenics and the methadone controls' CSDs were statistically different from the normal controls and the subacute schizophrenics. The results support earlier reports of long target duration required by chronic schizophrenics for feature recognition. Since retarded CSDs were obtained for methadone control but not for acute schizophrenics, the CSD does not qualify as a specificity or a vulnerability index for schizophrenia. A neurophysiological explanation is proposed for the findings.

Adult↗
PubMed1992

Schizophrenic feature recognition deficits are independent of task criterion.

The present study determined the minimal exposure time (i.e., critical stimulus duration (CSD) necessary for feature registration and recognition by normals and chronic schizophrenics. Our interest was whether the longer exposure times required by schizophrenics than by normals could be attributed to an inability of schizophrenics to maintain attention when the task criteria were stringent as opposed to 'loose'. The present findings support previous findings of impaired feature recognition by chronic schizophrenics. Chronic schizophrenics' and normals' CSDs were not affected by task criterion. The consistent performance by these groups on the 'loose' and 'rigid' task criteria suggest that if attentional lapses occur then they are as likely to occur for chronic schizophrenics as for normals and they are independent of the task's criterion. It is concluded that impaired feature registration for chronic schizophrenics is a consequence of a deficit at the earliest stage of encoding.

Adult↗
PubMed1992

Behavioral aspects of trichotillomania.

Trichotillomania is characterized by an inability to resist urges to pull out hair. It is estimated to occur in at least 1 out of 200 persons by college age. The disorder usually begins in childhood or adolescence with a chronic course more likely in patients with a later onset. Some investigators hypothesize a relationship between trichotillomania and obsessive compulsive disorder, but this proposal has not yet been substantiated. Little rigorous treatment research has been done, but the current treatments of choice are clomipramine and behavior therapy (habit reversal training).

Adult↗
PubMed1991

Cognitive deficits and psychopathology among former prisoners of war and combat veterans of the Korean conflict.

OBJECTIVE: This study was conducted to describe the long-term psychological and psychiatric sequelae of prisoner of war (POW) confinement against the backdrop of psychiatric evaluations of Korean conflict repatriates more than 35 years ago. METHOD: A group of 22 POWs and a group of 22 combat veteran survivors of the Korean conflict were compared on measures of problem solving, personality characteristics, mood states, and psychiatric clinical diagnoses by means of a battery of psychometric instruments and structured clinical interviews. RESULTS: Although the two groups were similar in background and personal characteristics, they differed in reports of life adjustment problems, complaints of physical distress, proficiency on cognitive tests, objectively measured personality characteristics, and assigned psychiatric diagnoses. CONCLUSIONS: Illustrated by a case report which describes the prolonged brutality of the Korean conflict POW experience for one individual, the results suggest that the psychiatric symptoms documented more than three decades ago have persisted in severity and chronicity. In addition to problems with cognitive deficits and complaints of bodily discomfort, most common among POW survivors were symptoms of suspiciousness, apprehension, confusion, isolation, detachment, and hostility.

Affect↗
PubMed1990

Assessment of long-term psychosocial sequelae among POW survivors of the Korean Conflict.

Psychological and psychiatric assessments were performed among 20 prisoner-of-war (POW) Korean-Conflict survivors. Results revealed extraordinary biological and psychological abuse with weight losses exceeding 35% of preservice weights and long-term cognitive, emotional, and behavioral sequelae. The full range of posttraumatic stress disorder symptoms was seen in 90% to 100% of the cases with high prevalence of co-morbidity, specifically mood (75%), other anxiety (45%), and alcohol abuse (20%) disorders. Documented by clinical investigators at POW release and now more than 30 years later, symptoms of apprehensiveness, confusion, detachment, and depression reflect the persistence of psychiatric morbidity over time.

Adaptation, Psychological↗
PubMed1990

Obsessive compulsive patients: familial frustration and criticism.

Familial factors such as attitudes toward illness, knowledge of disease process, and criticism of patients often play an important role in patient compliance and outcome in general medical practice as well as in psychiatric settings. As part of the initial assessment in a psychoeducational group for obsessive compulsive disorder patients and their significant others, nonpatients completed the Relative's Reactions Questionnaire and the Control of Symptoms Schedule. The patients completed the Perceived Criticism Measure. Results suggest that significant others experience frustration with the symptomatic behavior of their friend or family member with obsessive compulsive disorder and may respond too frequently with verbal criticism. The patients themselves reported a moderately high level of criticism from significant others at home. Further research is needed on a larger sample size and with nonpsychiatric and nonobsessive compulsive disorder psychiatric controls.

Adult↗
PubMed1989

A treatment strategy for psychogenic vomiting.

Although the literature supports the existence of psychogenic vomiting as a distinct psychiatric disorder, the DSM III-R does not include it as a diagnostic category. Of the numerous articles in the literature which describe this disorder, few discuss treatment. The purposes of this paper are to review the existing literature, to describe the family dynamics which are thought to precipitate the evolution of psychogenic vomiting in the identified patient, and to describe a treatment protocol which has been successfully employed in an outpatient setting. The illness is characterized as an eating disorder in terms of etiology, symptomatology, and treatment. A treatment strategy is described which includes insight-oriented psychotherapy with cognitive/behavioral interventions and family therapy. Two case studies are included which illustrate that a combined therapy approach is efficacious in treating psychogenic vomiting.

Adolescent↗
PubMed1988

Preattentive deficit in temporal processing by chronic schizophrenics.

Preattentive visual filtering by two types of neural cells (transient and sustained) constitutes the basic neural correlates underlying visual perception. Transient cells respond abruptly to temporal modulation and to the low spatial frequency components of visual stimuli. Their function is localization of objects and global perception (i.e., detection). Sustained cells respond slowly and selectively to high spatial frequencies and are believed to be responsible for the "oblique effect" (i.e., reduced responsiveness to obliquely oriented high spatial frequencies), which likely occurs at the striate cortex. Their function is to discern the details of an object (i.e., identification). The present study evaluated early visual processing in normal controls and schizophrenics by presenting vertical and oblique (45 degrees) spatial frequency gratings of 0.9 and 12 c/deg that were presented for 50, 100, 175, and 250-msec pulses. Threshold, in milliseconds, to detect an interstimulus interval (ISI) between two grating pulses was the dependent measure. Schizophrenics required longer ISIs for each grating duration, except for 250 msec, and longer ISIs for the 15 c/deg oblique grating. The results indicate that schizophrenics have a preattentive processing deficit that is further elaborated at the cortical level.

Adult↗
PubMed1988

Visible persistence in paranoid schizophrenics.

A visual temporal integration (i.e., visible persistence) task was performed by normal controls and paranoid schizophrenics. The task evaluated the critical duration (CD), which approximates the duration of peripheral persistence duration and post-CD persistence, which is possibly more associated with central processes. Subjects were required to report when temporally modulated spatial frequency patterns, which are known to have characteristic temporal processing rates, were pulsing "on-off" with a distinct "off" period. The dependent measure was the duration of visible persistence. An analysis of groups X spatial frequency duration (50, 75, 150, 300 msec) X spatial frequency (high, medium, low), with repeated measures on the last two variables, revealed that the second-order interaction was significant (p less than 0.05). Schizophrenics had shorter visible persistence only for the 300-msec presentation for the high spatial frequency pattern. Also, the CD of schizophrenics did not conform to the duration of normals on the high spatial frequency. The results are discussed in terms of the role high spatial frequencies plays in visual information processing and how shorter visible persistence by paranoid schizophrenics may reflect a premature termination of information necessary for synthesis into accurate percepts.

Adolescent↗
PubMed1987

Disordered spatiotemporal processing in schizophrenics.

Schizophrenics have been observed to process information slower than normal individuals. The present study evaluated spatiotemporal information processing by schizophrenics and normal controls by means of a contrast sensitivity task. Spatial frequency gratings (0.9, 3.8, 15 cycles/degree), temporally modulated at 0.0 stationary, 0.8, 3.25, 6.5, and 26.0 Hz, were presented to evaluate whether or not schizophrenics are deficient in processing patterns or temporal information. While the patterns were increasing linearly from 0% to 30% contrast, the subjects were required to discern when pattern or temporal changes first occurred. A multivariate Analysis of Variance revealed that schizophrenics were poorer at detecting temporal changes between 3.25 and 6.5 Hz, whereas they were able to detect patterns better on the low and poorer on the high spatial frequencies compared to normals. No differences were obtained for the stationary pattern. These results are discussed in terms of abnormal sensory gating occurring during the critical duration of temporal integration.

Adolescent↗
PubMed1979

An attitude survey of the effects of marijuana on sexual enjoyment.

Determined attitudes on the effects of marijuana on sexual enjoyment by self-report for a group of 84 graduate students of health sciences. The students were grouped in three categories: those who had sexual experience while under the influence of marijuana (experienced smokers), those who have smoked marijuana but who have not had such experience (non-experienced smokers), and non-smokers. Results are again inconclusive despite the fact that a majority in each category responded in a positive manner to the initial question concerning the effect of marijuana on the enjoyment of sexual intercourse. There is sufficient support to indicate that at least some experienced smokers have derived an enhancement of sexual pleasure while they were using marijuana. The implication is that there may be value in researching the use of marijuana in treatment of sexual disorders.

Adult↗