No description available.

Meehl�s (1962, 1989, 1990b) schizotypy and Tsuang et al.�s (1999b, 2000a, 2000b) schizotaxia are fundamentally different notions of the schizophrenia precursor. Both represent a categorical precursor but differ in the nature of their relationships to schizophrenia. Specifically, schizotypy is dimensional, unchanging despite the presence or remission of schizophrenia. In contrast, schizotaxia is a transitional precursor; the presence of schizophrenia signals the end of schizotaxia. There are also differences in the way in which risk is determined. Schizotypy is reflected in a variety of information processing and experiential aberrations, is typically assessed using self-report measures, and is best identified using taxometric analyses. In contrast, schizotaxia is characterised by negative symptoms of schizophrenia and neurocognitive impairment, can be assessed using standardised clinical measures, and is diagnosed at the individual case level. The aim of Phase 1 of this study was to investigate the manifest structure of Meehl�s schizotypy in a sample of psychiatric patients. The aims of Phase 2 were to determine if schizotypy group membership was associated with poorer functioning and to determine the nature of the relationship between Meehl�s (1962, 1989, 1990b) schizotypy and Tsuang et al.�s (1999b, 2000a, 2000b) schizotaxia. Participants in Phase 1 were 109 psychiatric patients and all completed a self-report measure of schizotypy, the Thinking and Perceptual Style Questionnaire (TPSQ; Linscott & Knight, 2004). Multivariate taxometric analyses of TPSQ subscales yielded evidence of a manifest group structure within the sample. The prevalence of the latent group, presumed to reflect schizotypy, was estimated to be 32% (SD = 8%), as yielded by MAXCOV analyses. MAXCOV analyses also yielded a mean indicator validity of 1.02; variance of 7; base rate estimates of .08; and a goodness of fit index of .98. MAMBAC analyses yielded a mean base rate of 56% (SD = 18%). Twenty-nine participants from Phase 1 took part in Phase 2. Fourteen were from the schizotypy group (had a p value of .85 or higher of schizotypy group membership) and 15 from the nonschizotypy group (had a p value of .03 or lower of schizotypy group membership). Participants completed tests of attention, verbal memory, and executive functioning. Negative symptoms of schizophrenia were also rated and diagnosis was determined using a diagnostic interview. The schizotypy group was significantly impaired relative to the nonschizotypy group on neuropsychological test scores spanning domains of attention, verbal memory, and executive functioning. A current DSM-IV diagnosis was made for 71% of the schizotypy group and 43% of the nonschizotypy group. Individuals were classified as having met criteria for schizotaxia if they had a negative symptom impairment and a neuropsychological impairment in two domains. A total of 7 people of 29 met criteria for schizotaxia, 6 of these people were from the schizotypy group. There was statistical evidence that Meehl�s (1962, 1989, 1990b) schizotypy and Tsuang et al.�s (1999b, 2000a, 2000b) schizotaxia are not independent. The proposed precursors for schizophrenia may reflect the same construct, not separate entities. Limitations and implications of these results are considered.

Bibliography: leaves 390-409. / vii, 409, 14, 12 leaves, [3] leaves of plates : col. ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Concerned with how fifty people diagnosed with schizophrenia invested their world with meaning, utilizing the resources which were available to them in their daily lives. "Extraordinariness" which has its basis in personal experience, is elaborated and multiplied by the social conditions and institutional structures of people's everyday lives. As a consequence of their placement within a field of deinstitutionalized psychiatric services, participants continually traversed the border between their own extraordinary experiences (which highlighted their distinctiveness) and those experiences which were taken for granted by themselves as well as others (and which allowed them to lay an equal claim to ordinariness). In this context, schizophrenia serves as a particularly apt case study in the limits and possibilities of intersubjectivity which is explored as the capacity to render experience meaningful to both self and others. / Thesis (Ph.D.)--University of Adelaide, Depts. of Anthropology and Psychiatry, 1999

Elevated serum homocysteine concentrations are neurotoxic and are strongly implicated as a risk factor for neuropsychiatric disease (Fabender, Mielke, Bertsch, & Hennerici, 1999; Kim & Pae, 1996; Kruman et al., 2000; Reutens & Sachdev, 2002). This study compares homocysteine levels in early stages psychosis patients and healthy controls. Data from 48 healthy controls were compared with 50 previously diagnosed psychosis patients, 15-25 years, and with a gender ratio males: females 7:3. Patients were outpatients or inpatients at ORYGEN Youth Health, with a diagnosis of first episode of psychosis defined as daily psychotic symptoms lasting longer than a week that could not be explained by other means such as “drug-induced” or “organic”. / All subjects were interviewed to collect information relating to family psychotic history. A possible history of psychotic disease in control subjects was tested using the SCID Psych Screening Module, drug use recorded using Alcohol Use Disorders Identification Test (AUDIT) (for alcohol use), The Modified Fagerström Tolerance Questionnaire (mFTQ) (for smoking), Opiate Treatment Index (OTI) (for opiate-type drugs). Dietary and medication histories were also taken. Blood tests were performed to determine serum homocysteine, serum folate, red blood cell folate and serum vitamin B12 levels. / An independent sample t test to compare homocysteine levels in patients and controls was performed. Serum homocysteine levels were significantly higher for patients (M = 12.9, S.D. = 3.6) than controls (M = 11.1, S.D. = 2.7) (t(96) = 2.7, p = 0.007, two-tailed). After General Linear Model (GLM) analysis it was found that group (patients or controls), and not serum folate, vitamin B12 and the T allele of MTHFR C677 polymorphism had significant effect on homocysteine levels. Thus a number of factors that may increase homocysteine levels were ruled out. / Although it was not possible to obtain a complete data set for some factors (alcohol, smoking and caffeine consumption) (a weakness of the study), strengths included consecutive recruitment, minimisation of selection bias, good matching for age and gender between patients and controls, and the consideration of (serum) folate and (serum) vitamin B12 as potential confounding variables. / A number of other studies have found significantly increased homocysteine levels in young patients compared with controls, particularly males. Most related studies favoured the homocysteine-psychosis link. / The probability of symptomatic recovery is very high (80-90%) after treatment for first episode psychosis (Robinson et al., 1999) and delayed treatment, but prolonged duration of treatment is associated with poorer response in treatment and worse outcome (Malla & Norman, 2002). This justifies studying homocysteine levels and cognitive function in that first period of psychosis. / This research offers evidence for the importance of serum homocysteine levels as showing involvement in the etiology of psychosis. Lowering homocysteine may have a beneficial effect on symptoms and cognitive dysfunction in psychotic illness. / Two randomised controlled trials have demonstrated benefit in psychotic illness of giving folate and consequently reducing homocysteine.(Godfrey & Toone, 1990; Levine et al., 2006b). Benefits of taking folate were found in both trials for both cognition and psychotic symptoms. By reducing homocysteine levels early in the illness, some of the excess cardiovascular mortality may be prevented. / Secondary prevention of CVD does not appear to influence outcome (Hermann, Herrmann, & Obeid, 2007), so the right time to intervene and reduce risk would appear to be early in the course of psychosis. Additionally, by lowering homocysteine cognitive functioning and psychotic symptoms may be improved (Levine et al., 2006b).

Bibliography: leaves 390-409. / vii, 409, 14, 12 leaves, [3] leaves of plates : col. ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Concerned with how fifty people diagnosed with schizophrenia invested their world with meaning, utilizing the resources which were available to them in their daily lives. "Extraordinariness" which has its basis in personal experience, is elaborated and multiplied by the social conditions and institutional structures of people's everyday lives. As a consequence of their placement within a field of deinstitutionalized psychiatric services, participants continually traversed the border between their own extraordinary experiences (which highlighted their distinctiveness) and those experiences which were taken for granted by themselves as well as others (and which allowed them to lay an equal claim to ordinariness). In this context, schizophrenia serves as a particularly apt case study in the limits and possibilities of intersubjectivity which is explored as the capacity to render experience meaningful to both self and others. / Thesis (Ph.D.)--University of Adelaide, Depts. of Anthropology and Psychiatry, 1999

Thesis (Ph. D.)--University of North Carolina at Greensboro, 2007. / Title from PDF t.p. (viewed Feb. 29, 2008). Directed by Thomas R. Kwapil; submitted to the Dept. of Psychology. Includes bibliographical references (p. 79-111).

Diss. (sammanfattning) Göteborg : Univ. , 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 6 uppsatser.

Diss. (sammanfattning) Göteborg : Univ. , 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 135-150). Also available online in ProQuest, free to University of Oregon users.