Browsing by Author "Horn, Neil"

Now showing 1 - 8 of 8
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    Open Access
    A retrospective observational study of the effectiveness of long acting antipsychotic injectable on hospital admissions
    (2018) Charles, Bhaskaran Nathamaniar; Horn, Neil; Williams-Ashman, Peter
    Background: The impact on hospitalisations/ relapse rates of utilising long-acting antipsychotic injectable (LAIs) in a South African population suffering from chronic psychotic spectrum mental illness is poorly researched. Aim: To compare the duration and number of hospitalisation episodes 12 and 24 months before and after the initiation of a LAI. Setting: Valkenberg Hospital’s adult acute inpatient psychiatry services. Method: This was a retrospective naturalistic observational mirror-image study. Hospitalisation was utilised as a proxy for relapse. Results: Sixty-one patients were identified for the study. A comparison of the 12 months before LAI initiation to the 12 months following LAI initiation showed a reduction in the number of admissions of 44% (55 to 31), and a reduction in the number of inpatient days of 23% (1892 to 1464). There was a statistically significant reduction in the median number of hospital admissions (p = 0.005) and median inpatient days (p = 0.040). Comparing the 24 months before to the 24 months following LAI initiation, there was a reduction in the number of admissions of 30% (91 to 64) and inpatient days of 4% (3477 to 3355). There was a statistically significant reduction in the median number of hospital admissions (p = 0.014) and a non-statistically significant reduction in median days (p = 0.428). Conclusion: The prescription of a LAI reduced the duration and number of hospital admissions over a 12-month period. After 24 months, there were fewer admissions but no significant reduction in the number of inpatient days. This study supports findings of international mirror-image studies.
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    A retrospective study of outcomes after referral to the early intervention in psychosis programme at Valkenberg Psychiatric Hospital
    (2023) Setjie, Sewela; ; ; Horn, Neil; Rodwell Catherine
    Background. Psychotic Disorders affect more than 1% of the South African adult population and have a chronic course that is associated with high rates of morbidity and mortality. The implementation of early intervention strategies may reduce the severity of these disorders. Little is known about the effectiveness of these interventions in South Africa and few longerterm studies have been undertaken internationally. Aim. This study aimed to measure the effectiveness of an Early Intervention and Support (EISH) service at reducing readmission to hospital in patients with psychotic disorders. Setting. Valkenberg Psychiatric Hospital, Cape Town. The EISH Team is an outpatient service consisting of psychiatrists, a psychologist, an occupational therapist, psychiatric nurses and social workers. Methods. Retrospective cohort study. Hospitalisation during the two years after discharge from the index admission was measured in 100 subjects who attended EISH and 100 who had treatment as usual (TAU). Readmission rate, average length of stay (ALOS), and time to readmission to District Hospitals (DH) and Tertiary Psychiatric Hospitals (TPH) were calculated. Results. Readmission Rates were three times higher in TAU compared to EISH patients for both types of Hospital. For TAU subjects compared to EISH subjects: ALOS was longer (59 vs 13 days), and days to readmission were fewer (187 vs 320 days). All differences were statistically significant (ps < .05). Conclusion. EISH intervention at Valkenberg Hospital was useful in reducing readmission rate, ALOS, and time to readmission in patients with Psychotic disorders. Prospective controlled trials are required to confirm the efficacy of this intervention.
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    Effects of bipolar disorder on intrinsic brain networks
    (2016) Starke, Jonathan Alan; Horn, Neil; Beckmann, Christian
    Introduction: Bipolar disorder (BD) is a brain network disorder that affects cognitive and emotional functioning, and is associated with prefrontal and/or limbic dysfunction. Functional Magnetic Resonance Imaging (fMRI) allows identification of intrinsic brain networks (IBN), like the default mode network (DMN) and executive control network (ECN), which are consistent with previously established functional and anatomical relationships within the brain. Analysing the functional connectivity (integrity, extent and inter-relationships) of these networks, allows a deeper understanding of brain function in health and disease. In BD, there are functional connectivity changes in the DMN, ECN and cerebellar network (CERN). We evaluate IBN in BD, to explore changes in the functional connectivity between the cerebellum, fronto-cortical and paralimbic regions. Methods: Data from 14 BD subjects and 10 control subjects was analysed after fMRI. Changes were evaluated in 3 IBN (DMN, ECN and CERN) using an FMRIB Software Library (FSL) pipeline: MELODIC/ICA-AROMA, dual-regression, randomise and Local False Discovery Rate (FDR) to identify changes in functional connectivity bipolar subjects compared to controls. Results: Subjects with BD showed decreased connectivity between the CERN and a cluster in the right precuneus; and between the ECN and a cluster in the left OFC. There was also increased connectivity between the ECN and a cluster in the left temporal pole. No connectivity changes involving the DMN were identified. Voxels within the clusters were significant at p < 0.05 with local FDR. Peaks within the clusters remained significant after further Bonferroni correction for multiple comparisons (p < 0.017). Conclusion: The finding of altered functional connectivity in BD, in networks and regions involved in cognitive/emotional processes, highlights its complex neurobiology, and suggests that abnormal connectivity may help to explain the clinical picture. These findings should be replicated with larger samples, but may represent a further advance in understanding the role of functional connectivity in the pathology of BD, and contribute to laying the foundation for functional neuroimaging as a diagnostic tool in psychiatry.
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    The genetics of lithium-induced adverse drug reactions in bipolar disorder patients : a pilot study
    (2013) Weideman, Reinette; Ramesar, Raj; Horn, Neil
    Lithium is regarded as the first-line pharmacotherapy for the treatment of acute mood episodes, suicide prevention and prophylactic treatment in patients with bipolar disorder (BPD). Response to lithium has a strong genetic component and lithium-responders have an increased frequency of BPD among their family members. Lithium has a narrow therapeutic index and 75-90% of patients on long-term lithium treatment experience one or more side effects, such as weight gain, cognitive decline and skin problems, amongst at least 20 side effects. The research project is immersed in a larger project on the genetics of bipolar disorder, in which a large number of individuals in families have been investigated over several years. The present pilot study explored whether single nucleotide polymorphisms (SNPs) within GSK3B, AKT1, ARRB2, GRIA2 and PPPARGC1A could be associated with the incidence and severity of lithium-induced side effects.
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    Mindfulness based cognitive therapy improves frontal control in bipolar disorder: a pilot EEG study
    (BioMed Central Ltd, 2012) Howells, Fleur; Ives-Deliperi, Victoria; Horn, Neil; Stein, Dan
    BACKGROUND: Cognitive processing in Bipolar Disorder is characterized by a number of attentional abnormalities. Mindfulness Based Cognitive Therapy combines mindfulness meditation, a form of attentional training, along with aspects of cognitive therapy, and may improve attentional dysfunction in bipolar disorder patients. METHODS: 12 euthymic BD patients and 9 control participants underwent record of electroencephalography (EEG, band frequency analysis) during resting states (eyes open, eyes closed) and during the completion of a continuous performance task (A-X version, EEG event-related potential (ERP) wave component analysis). The individuals with BD completed an 8-week MBCT intervention and record of EEG was repeated. RESULTS: (1) Brain activity, individuals with BD showed significantly decreased theta band power, increased beta band power, and decreased theta/beta ratios during the resting state, eyes closed, for frontal and cingulate cortices. Post MBCT intervention improvement over the right frontal cortex was seen in the individuals with BD, as beta band power decreased. (2) Brain activation, individuals with BD showed a significant P300-like wave form over the frontal cortex during the cue. Post MBCT intervention the P300-like waveform was significantly attenuated over the frontal cortex. CONCLUSIONS: Individuals with BD show decreased attentional readiness and activation of non-relevant information processing during attentional processes. These data are the first that show, MBCT in BD improved attentional readiness, and attenuated activation of non-relevant information processing during attentional processes.
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    Psychosis and relapse in bipolar disorder are related to GRM3 DAOA and GRIN2B genotype
    (2010) Dalvie, S; Horn, Neil; Nossek, Christel; van der Merwe, L; Stein, Dan; Ramesar, Raj
    Objective: Dysfunction in glutamate signalling is thought to play a role in the pathophysiology of bipolar disorder (BD). There is evidence of associations between single nucleotide polymorphisms (SNPs) in GRM3, GRIN2B, and DAOA genes and the diagnosis of BD. In this pilot study, we investigated the frequency of SNP variants in these 3 genes within South African population groups, and assessed interactions between genes and phenotypes of BD disease severity. Method: Multiplex SNaPshotTM PCR was used to genotype 191 case and 188 control samples. Cases comprised of 191 individuals in a South African cohort of mixed ancestry and Caucasians, with BD Type 1. Phenotypes of BD disease severity were: age of onset, number of illness episodes, number of hospitalisations for depression or mania and history of psychotic symptoms. Results: There were no significant difference in SNP allele frequencies between cases and controls. In the case-only analysis, the GRM3 rs6465084 heterozygote was associated with a 4-fold increased risk of lifetime history of psychotic symptoms, and the specific variants within the gene pair, DAOA and GRIN2B, had a significant interaction with the number of hospitalisations for mania, with lowest admission rates associated with both pairs of ancestral alleles.Conclusion: In BD, variations in glutamatergic genes may influence phenotypes related to the severity of illness. Speculatively, newly derived genes associated with various evolutionary advantages, may also increase the risk for more severe BD. These preliminary findings deserve validation in a larger cohort.
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    A systematic review of DTI studies in Bipolar Disorder
    (2012) Nortje, Gareth; Horn, Neil
    In the last decade, multiple diffusion tensor imaging (DTI) studies have revealed changes in the microstructure of white matter in bipolar disorder. The results are poorly replicated and inconsistent, however, with some authors suggesting a predominance of alterations in fronto-limbic white matter. Preliminary reading of the literature suggests that white matter changes as revealed by DTI may be more widespread throughout the brain. Two extant reviews have each been limited by including all affective disorders or by a methodology which ignores tracts and discards potentially meaningful data. This background in the review includes a detailed exposition of the main DTI techniques and shortcomings. The review aims to determine whether certain white matter tracts are affected preferentially in the brain, as opposed to more diffuse white matter involvement. It also aims to determine if there is an anterior-posterior gradient of abnormalities. This review systematically collates data relating to tract involvement as demonstrated by DTI, as well as data regarding anterior-posterior distribution of abnormalities. Medline and EMBASE databases are searched systematically to select original papers comparing a bipolar group with healthy controls, using DTI, in adults, and reporting at least fractional anisotropy (FA). Subject, scan and analysis characteristics are extracted. Details of affected tracts are collated, as is the y-axis (anterior/posterior) of the most affected ('peak') voxels.
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    Systematic review of imaging studies in the lateral orbitofrontal circuit in bipolar type I disorder
    (2013) Yorke, Neil; Horn, Neil
    The aim of this study was to review the available published structural magnetic resonance imaging (MRI) data in bipolar type I disorder, looking for any evidence of a change in size of the structures in lateral orbitofrontal circuits relative to the conceptually unaffected motor circuit. Structures in the motor circuit will thus act as an internal control. We will additionally look at healthy controls as an external control.