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Dive into the research topics where Natasha Keyter is active.

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Featured researches published by Natasha Keyter.


Acta Psychiatrica Scandinavica | 2005

Duration of untreated psychosis and outcome in first-episode psychosis. Perspective from a developing country

P. Oosthuizen; Robin Emsley; Natasha Keyter; D. J. H. Niehaus; Liezl Koen

Objective:  To investigate the association between duration of untreated psychosis (DUP) and treatment outcome in a sample of subjects from a developing country.


The International Journal of Neuropsychopharmacology | 2004

A randomized, controlled comparison of the efficacy and tolerability of low and high doses of haloperidol in the treatment of first-episode psychosis

Piet Oosthuizen; Robin Emsley; H. Jadri Turner; Natasha Keyter

While haloperidol is still widely used in the treatment of psychoses, the optimal daily dose remains a topic of controversy, particularly in first-episode psychosis. Previous studies have suggested that doses as low as 2 mg/d may be effective, whereas others have indicated superiority for higher over lower doses. This double-blinded, randomized controlled study compared the efficacy and tolerability of 2 vs. 8 mg/d of haloperidol over 6 wk in 40 subjects with first-episode psychosis. Both treatments were equally effective in reducing the PANSS Total and subscale scores. The low dose of haloperidol was better tolerated, with fewer extrapyramidal side-effects, less frequent use of anticholinergic medication and smaller elevations in prolactin levels. Using a low dose of haloperidol is at least as effective as, and better tolerated than a high dose of haloperidol in the treatment of first-episode psychosis.


Schizophrenia Research | 2002

Depressive symptoms at baseline predict fewer negative symptoms at follow-up in patients with first-episode schizophrenia.

Piet Oosthuizen; Robin Emsley; Mimi C. Roberts; Jadri Turner; Linda Keyter; Natasha Keyter; Martijn Torreman

There is uncertainty regarding the prognostic value of depressive symptoms in schizophrenia, having previously been associated with both favourable and poor outcome. This study investigated the relationship between baseline depressive symptoms and treatment outcome at 6, 12 and 24 weeks in 80 subjects with first-episode schizophrenia or schizophreniform disorder in terms of PANSS total and subscale score changes. No significant association was found between baseline PANSS depression factor scores and PANSS total and subscore changes. However, a significant inverse correlation between baseline depression scores and negative scores at 6, 12 and 24 weeks was found (p=0.044, 0.023 and 0.012, respectively). Multiple regression analysis indicated that this finding could not be explained on the basis of age, gender or duration of untreated psychosis. These findings support previous work suggesting that high baseline depressive scores predict favourable outcome.


Journal of Psychopharmacology | 2001

Determining the optimal dose of haloperidol in first-episode psychosis

Piet Oosthuizen; Robin Emsley; Jadri Turner; Natasha Keyter

Uncertainty exists as to the most appropriate dose of haloperidol in first-episode psychosis. This study set out to determine whether ultra-low doses of haloperidol could successfully treat patients with first-episode psychosis. Thirty-five patients with a first episode of psychosis were treated with haloperidol in an open label, fixed protocol over a 12-week period with doses restricted to 1 mg per day for the first 4 weeks. Twenty-nine (83%) remained on haloperidol after 12 weeks at a mean dose of 1.78 mg per day, 16 (55%) had stabilized on 1 mg/day or less. The mean percentage reduction in Positive and Negative Symptom Scale score between baseline and 6 and 12 weeks was 30.3% (SD 20.9%) and 41.4% (SD 16.6%), respectively. There were no significant differences in mean extrapyramidal symptom ratings between baseline and 12 weeks. Ultra-low doses of haloperidol are effective and well tolerated in first-episode psychosis. Initial doses should be maintained for a sufficient period of time to allow for the medication to take full effect.


Australian and New Zealand Journal of Psychiatry | 2004

Violence in male patients with schizophrenia: risk markers in a South African population

Liezl Koen; Craig J. Kinnear; Valerie A. Corfield; Robin Emsley; Esme Jordaan; Natasha Keyter; Johanna C. Moolman-Smook; Dan J. Stein; D. J. H. Niehaus

OBJECTIVE We investigate the role of functional variants in the catecholamine-O-methyl transferase gene (COMT) and the monoamine oxidase-A gene (MOA-A), as well as previously identified non-genetic risk factors in the manifestation of violent behaviour in South African male schizophrenia patients. METHOD A cohort of 70 acutely relapsed male schizophrenia patients was stratified into violent and non-violent subsets, based on the presence or absence of previous or current violent behaviour. Standardized violence rating scales were also applied and the COMT/NlaIII and MAO-A promoter region variable number of tandem repeats (VNTR) polymorphisms were genotyped. RESULTS A multiple logistic regression model based on the clinical, genetic and socio-demographic variables indicated that delusions of control (OR = 3.7, 95% CI = 1.21-11.61) and the combined use of cannabis and alcohol (OR = 6.89, 95% CI = 1.28-37.05) were two significant predictors of violent behaviour in this schizophrenia population. No association was found between the tested polymorphisms and violent behaviour. CONCLUSIONS Although the sample size may have limited power to exclude a minor role for these specific gene variants, such a small contribution would have limited clinical relevance given the strong significance of the non-genetic markers. These findings suggest that currently proactive management of violent behaviour in this schizophrenia population should continue to be based on clinical predictors of violence.


Psychopathology | 2004

A Culture-Bound Syndrome ‘Amafufunyana’ and a Culture-Specific Event ‘Ukuthwasa’: Differentiated by a Family History of Schizophrenia and other Psychiatric Disorders

Dana Niehaus; P. Oosthuizen; Christine Lochner; Robin Emsley; Esme Jordaan; N.I. Mbanga; Natasha Keyter; Claudine Laurent; J.-F. Deleuze; Dan J. Stein

Background: ‘Amafufunyana’ and ‘ukuthwasa’ are two culture-specific descriptive terms used by Xhosa traditional healers to explain aberrant behavioral and psychological phenomena. Some overlap between these conditions and schizophrenia (DSM-IV) is apparent. The aim of this study was to determine the extent to which amafufunyana and ukuthwasa were used as cultural explanatory models by traditional healers for DSM-IV-defined schizophrenia and whether there were significant phenomenological differences in schizophrenia symptoms in patients with the diagnosis of amafufunyana rather than ukuthwasa. Sampling and Methods: Xhosa patients with schizophrenia underwent a structured clinical diagnostic interview (Diagnostic Interview for Genetic Studies). The use of traditional diagnostic and treatment methods was assessed by structured open-ended interviewer-rated questions. The sample was then stratified for the presence/absence of a past/current diagnosis of amafufunyana and/or ukuthwasa. The clinical parameters were compared across groups by means of the χ2 or Student t tests. Results: 247 adult subjects participated in the study. 106 (53%) patients reported a previous diagnosis of amafufunyana, and 9 (4.5%) reported a diagnosis of ukuthwasa. A family history of schizophrenia (p = 0.004) or any psychiatric disorder (p = 0.008) was more common in the ukuthwasa group. Subjects with a primary diagnosis other than amafufunyana or ukuthwasa were more likely to be married (p = 0.004), to have a history of stressor(s) prior to illness onset (p = 0.026), to be from a rural environment (p = 0.007) or to have a history of cannabis abuse/dependency (p = 0.015). Conclusion: The culture-bound syndrome amafufunyana and the culture-specific phenomenon of ukuthwasa are both used to explain symptoms in patients with schizophrenia (DSM-IV). Identification of cases as amafufunyana and ukuthwasa may correlate with a distinction between familial and sporadic cases of schizophrenia. Whether the positive connotations associated with ukuthwasa, as opposed to the more negative connotations associated with amafufunyana, hold any implications for the treatment or prognosis of schizophrenia remains to be clarified.


South African Medical Journal | 2003

Prevalence of obsessive compulsive disorder in first- and multi-episode male patients with schizophrenia-spectrum disorders

Liesel Koen; Piet Oosthuizen; Dana Niehaus; Robin Emsley; Jacqueline E. Muller; Dan J. Stein; Natasha Keyter; Christine Lochner; Soraya Seedat

CITATION: Koen, L. et al. 2003. Prevalence of obsessive compulsive disorder in first- and multi-episode male patients with schizophrenia-spectrum disorders. South African Medical Journal,


The Journal of Clinical Psychiatry | 2002

Ethnicity and treatment response in schizophrenia: a comparison of 3 ethnic groups.

Robin Emsley; Mimi C. Roberts; Solomon Rataemane; Janus Pretorius; Piet Oosthuizen; Jadri Turner; Dana Niehaus; Natasha Keyter; Dan J. Stein


The Journal of Clinical Psychiatry | 2003

Incidence of Tardive Dyskinesia in First-Episode Psychosis Patients Treated With Low-Dose Haloperidol

Piet Oosthuizen; Robin Emsley; J S Maritz; Jadri Turner; Natasha Keyter


Suicide and Life Threatening Behavior | 2004

Suicide Attempts in an African Schizophrenia Population: An Assessment of Demographic Risk Factors.

D. J. H. Niehaus; Claudine Laurent; Esme Jordaan; Liezl Koen; Piet Oosthuizen; Natasha Keyter; James E. Muller; N. I. Mbanga; J-F Deleuze; Jacques Mallet; Dan J. Stein; Robin Emsley

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Robin Emsley

University of Cape Town

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Dan J. Stein

University of Cape Town

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Jadri Turner

Stellenbosch University

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Dana Niehaus

Stellenbosch University

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Esme Jordaan

University of the Western Cape

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Liezl Koen

Stellenbosch University

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