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Modelling the dynamics of methamphetamine abuse in the Western CapeKalula, Asha Saidi 03 1900 (has links)
Thesis (MSc (Mathematical Sciences))--University of Stellenbosch, 2011. / Includes bibliography / ENGLISH ABSTRACT: The production and abuse of methamphetamine has increased dramatically in South Africa,
especially in the Western Cape province. A typical methamphetamine use cycle consists of
concealed use after initiation, addiction, treatment and recovery. The model by Nyabadza
and Musekwa in [32], is extended to include a core group, fast and slow progression to
addiction. The model is analysed analytically and numerically using mass action incidence
function and non-linear incidence function. The analysis of the model with mass action
incidence is presented in terms of the methamphetamine epidemic threshold R0. The
analysis shows that the drug free equilibrium is locally asymptotically stable when R0 <
1 and drug persistent equilibrium is locally asymptotically stable when R0 > 1. The
model also exhibits a backward bifurcation. Sensitivity analysis of the model on R0 is
performed. The most sensitive parameters are transmission rate and recruitment rate
of individuals into the core group. The non-linear incidence incorporates innovators and
behaviour change. Analytically, the model is analysed in the absence of behaviour change.
With behaviour change two cases were considered. Firstly without innovators and secondly
with innovators. In the absence of innovators the non-linear incidence reduced to standard
incidence and similar results to the ones in the first model were obtained. With the presence
of innovators there is no drug free equilibrium. Numerically we fit the model to data on
the number of patients who enter into treatment centers for rehabilitation. Using the
fitted model, we determine the prevalence and incidence of methamphetamine abuse. We
investigate the impact of behaviour change, ‘reinfection’ rate as well as uptake rate into
treatment on prevalence. Our results suggest that intervention and prevention programs
focusing on behaviour change and uptake rate into treatment would reduce the prevalence.
Projections are made to determine the possible long term trends of the prevalence of
methamphetamine abuse in the Western Cape. We give suggestions related to data that
should be collected from a modelling perspective. / AFRIKAANSE OPSOMMING: Die vervaardiging en misbruik van metamfetamien het dramaties in Suid-Afrika toegeneem,
veral in die Wes-Kaap provinsie. ’n Tipiese metamfetamien gebruiksiklus bestaan uit heimlike
gebruik na aanvang, verslawing, behandeling en herstel. Die model deur Nyabadza en
Musekwa in [32], is uitgebrei om ’n kerngroep in te sluit, vinnige en stadige verloop tot
verslawing. Die model is analities en numeries ontleed deur van massa-aksie insidensie
funksie en ’n nie-liniêre insidensie funksie gebruik te maak. Die ontleding van die model
met massa-aksie insidensie word voorgestel in terme van die metamfetamien epidemiese
drempel R0. Die ontleding toon dat die dwelmvrye ewewig lokaal asimptoties stabiel is as
R0 < 1 en die dwelmblydende ewewig is lokaal asimptoties stabiel as R0 > 1. Die model
beeld ook ’n terugwaartse bifurkasie uit. Sensitiwiteitsontleding van die model ten opsigte
van R0 is uitgevoer. Die mees sensitiewe parameters is die oordraagbaarheidskoers
en die rekrute koers van individue in die kerngroep in. Die nuwelinge en gedragsverandering
word deur die nie-liniêre insidensie opgeneem. Analities, is die model ontleed in
die afwesigheid van gedragsverandering. Met gedragsverandering is twee gevalle beskou.
Eerstens sonder nuwelinge en tweedens met nuwelinge. In die afwesigheid van nuwelinge is
die nie-liniêre insidensie herlei tot standaard insidensie en soortgelyke resultate is verkry,
as dié wat in die eerste model verkry is. Met die aanwesigheid van nuwelinge is daar geen
dwelmvrye ewewig nie. Numeries pas ons die model aan die data wat betrekking het met
die aantal pasiënte wat in rehabilitasie sentra opgeneem word vir behandeling. Deur die
gepaste model te gebruik, het ons die voorkoms en insidensie van metamfetamien misbruik
bepaal. Ons ondersoek die impak van gedragsverandering, “re-infeksie” koers sowel as die
koers van opname in behandeling op voorkoms. Ons resultate toon dat intervensie- en
voorkomingsprogramme sal voorkoms verlaag, wat op die gedragsverandering en die koers
van opname in behandeling konsentreer. Die model is ook gebruik om die aantal metamfetamien
gebruikers te projekteer. Ons maak voorstelle verwant aan die data, wat vanuit
‘n modellerings-oogpunt ingesamel moet word.
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Modelling the dynamics of alcohol and methamphetamine co-abuse in the Western Cape Province of South AfricaOrwa, Titus Okello 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Clinical results have indicated that abuse of multiple drugs/substances has devastating
health and social consequences. The combined abuse of alcohol and the highly
addictive methamphetamine has worsened the drug epidemic in South Africa, especially
in the Western Cape Province. Using non-linear ordinary differential equations,
we formulate a deterministic mathematical model for alcohol-methamphetamine coabuse
epidemic. We prove that the growth of the co-abuse epidemic is dependent
on the threshold parameters of the individual substances of abuse. The substance
with the maximum reproduction number dominates the epidemic. We also prove
that the equilibria points of the co-abuse sub-models are locally and globally asymptotically
stable when the sub-model threshold parameters are less than unity. Using
parameters values derived from the sub-model fittings to data, a population estimate
of co-users of alcohol and methamphetamine under treatment is estimated with a
prevalence of about 1%. Although the results show of a small proportion of co-users
of alcohol and methamphetamine in the province, the prevalence curve is indicative
of a persistent problem. Numerical simulation results reveal that co-abuse epidemic
would persists when both reproduction numbers are greater than one. Results from
sensitivity analysis shows that the individual substance transmission rates between
users of methamphetamine and/or alcohol and the general susceptible population
are the most vital parameters in the co-abuse epidemic. This suggests the need to emphasise
on preventive measures through educational campaigns and social programs
that ensure minimal recruitment into alcohol or methamphetamine abuse. Model
analysis using the time-dependent controls (policies) emphasizes the need to allocate
even more resources on educational campaigns against substance abuse and on effective
treatment services that minimizes or eliminates rampant cases of relapse into
substance abuse. / AFRIKAANSE OPSOMMING: Kliniese resultate toon dat die misbruik van meer as een dwelmmiddel verwoestende
gesondheids-en sosiale gevolge het. Die gekombineerde misbruik van alkohol
en die hoogsverslawende methamphetamine het die dwelm-epidemie in Suid-Afrika
vererger, veral in die Wes-Kaapse provinsie. Deur van nie-lineere gewone diffensiaalvergelykings
gebruik te maak, formuleer ons ’n deterministiese wiskundige model
vir epidemie van die gesamentlike misbruik van alkohol en methamphetamine. Ons
toon aan dat die groei van die sogenaamde mede-misbruik epidemie afhanklik is van
die drumpelparameters van die individuele middels wat misbruik word. Die middels
met die grootste voortbringende syfer domineer die epidemie. Ons bewys ook dat
die ekwilibriumpunte van die mede-misbruik submodelle plaaslik en globaal asimptoties
stabiel is wanneer die sub-model drumpelparameters kleiner as een is. Deur die
submodelle op werklike data te pas word waardes vir die drumpelparameters afgelei
en word daar beraam dat daar ongeveer 1% van die populasie mede-misbruikers
van alkohol en methamphetamine onder behandeling is. Alhoewel die data ’n klein
persentasie van mede-misbruikers van alkohol en methamphetamine in die provinsie
toon, dui die voorkomskurwe op ’n groeiende endemie en voortdurende probleem.
Resultate uit numeriese simulasie toon dat die mede-misbruik epidemie sal
voortduur indien beide reproduserende syfers groter as een sal wees. Resultate van
sensitiwiteitsanalise toon dat die individuele middeloordragkoerse tussen gebruikers
van methamphetamine en/of alkohol en die gewone vatbare populasie die mees
noodsaaklike parameters in die mede-misbruik epidemie is. Dit stel voor dat daar
meer klem gelê moet word op voorkomingsmaatreëls deur opvoedkundige veldtogte
en sosiale programme om te verseker dat minder alkohol en/of methamphetamine
misbruik sal word. Model-analise wat gebruik maak van tyd-afhanklike kontroles
(beleide) lê verder klem op die feit dat selfs meer hulpbronne aan opvoedkundige
veldtogte teen dwelmmisbruik toegewy moet word, asook die effektiewe behandeling
wat gevalle van terugval in dwelmmisbruik sal minimeer of elimineer.
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Reflections on the life-world experiences of the adolescent "tik" use.Swartz-Filies, Sylnita. January 2007 (has links)
<p>Substance abuse among adolescents is a global problem and South Africa is no exception. In the Western Cape there is an alarming popularity and increased use of an illicit highly addictive substance, locally known as 'tik-tik'/methamphetamine. Adolescents are particularly vulnerable to the neurotoxic effects of this substance and there is an urgent need to address the 'tik-tik' problem in the Westen Cape. Tik/methamphetamine has thus become a great concern to educators, social workers and health practitioners in the province. The goal of this study was to explore the life-world of the adolescent methamphetamine/'tik-abusers' in order to describe their experiences of personal, social and environmental issues in the process of tik-addiction.</p>
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Reflections on the life-world experiences of the adolescent "tik" use.Swartz-Filies, Sylnita. January 2007 (has links)
<p>Substance abuse among adolescents is a global problem and South Africa is no exception. In the Western Cape there is an alarming popularity and increased use of an illicit highly addictive substance, locally known as 'tik-tik'/methamphetamine. Adolescents are particularly vulnerable to the neurotoxic effects of this substance and there is an urgent need to address the 'tik-tik' problem in the Westen Cape. Tik/methamphetamine has thus become a great concern to educators, social workers and health practitioners in the province. The goal of this study was to explore the life-world of the adolescent methamphetamine/'tik-abusers' in order to describe their experiences of personal, social and environmental issues in the process of tik-addiction.</p>
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I'm Not Gonna Be Like That Guy: Exploring the Montana Meth Project Through the Eyes of That GuyFerestad, Jaysen Nicole 25 November 2013 (has links)
Graphic images of meth addicts have swept across Montana in television, radio and print ads as part of the state's latest anti-drug campaign, the Montana Meth Project. From a labeling perspective, the negative portrayal of meth addicts in these ads has significant implications for meth addicts in terms of their reintegration. The unintended population of drug addicts potentially affected by public service campaigns has failed to gain attention in the literature despite the implications suggested by labeling theory. This poses a significant gap in our knowledge and understanding, which this study addresses through the voice of recovering meth addicts. This study explored the significance of the campaign with regard to the worldview of recovering meth addicts and the implications of this worldview with regard to their reintegration. In particular, the study examined 1) addict perceptions of the campaign's impact on community 2) addict perceptions of the campaign's personal impact 3) addict perceptions of the significance of social bonds 4) the implications of these perspectives from the theoretical standpoint of Labeling and Social Bond theory.
In-depth interviews were conducted among a sample of twenty recovering meth addicts at a treatment facility in Grenadier, Montana as well as one active meth user. This form of data collection was chosen due to the exploratory nature of the study as well the significance of perception suggested by the Symbolic-Interaction perspective (Cooley 1902). The study revealed that the Montana Meth Project does have a significant impact on the worldview of the participants. When the participants believe the campaign has a positive impact on the community - creating awareness, understanding and acceptance - the campaign is viewed as a tool in their reintegration. However, as the bulk of the findings suggest, when the participants believe the campaign has a negative impact - stereotypes, labeling, stigmatization and differential treatment - the campaign is viewed as a barrier to their reintegration. With such a negative reaction in the worldview of the participants, the mainstream world including family, friends and the community did not appear to be at the forefront of their reintegration. Rather, a subculture of recovering addicts acts as the source of positive social bonds and the most significant in the reintegration of the participants. The findings of this study demonstrate the impact anti- drug campaigns, and particularly scare campaigns using a public service approach, can have on the unintended audience of drug addicts.
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Temporally distinct impairments in cognitive function following a sensitizing regimen of methamphetamineJanetsian, Sarine Sona 01 August 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Methamphetamine (MA) is a widely abused psychostimulant that has been shown to evoke an array of neurobiological abnormalities and cognitive deficits in humans and in rodent models (Marshall & O'Dell, 2012). Alterations in cognitive function after repeated drug use may lead to impaired decision-making, a lack of behavioral control, and ultimately the inability to abstain from drug use. Human studies have shown that alterations in neurobiology resulting from prolonged MA use may lead to a number of cognitive deficits, including impairments in executive function, learning, memory, and impulsivity. These impairments, specifically those that engage the prefrontal cortex (PFC) or hippocampus (HC), may persist or recover based on the duration of abstinence. In rodents, repeated intermittent injections of MA yield protracted changes in neurobiology and behavior, which have been shown to effectively model a number of the biological and cognitive abnormalities observed in addiction. In order to assess the temporal evolution of impaired cognitive function throughout abstinence, sensitization was first induced in rats (7 x 5.0 mg/kg MA over 14 days). MA-treated rats initially exhibited a robust increase in locomotion that transitioned to stereotypy as the induction phase progressed. Then, the effects of MA sensitization on social interaction (SI), temporal order recognition (TOR) and novel object recognition (NOR) was assessed at one-day and 30-days post induction. No differences were observed in SI in either group or after a single injection of MA. However, an acute injection of 5.0 mg/kg of MA 30-minutes prior to testing dramatically reduced SI time. Impairments in TOR and NOR were observed in MA-treated rats after one day of abstinence, and impairments in TOR, but not NOR, were observed on day 30 of abstinence. No differences in TOR and NOR after a single injection of MA or saline were observed. These data establish that after 30 days of abstinence from a sensitizing regimen of MA, the ability to recall the temporal sequence that two stimuli were encountered was impaired and that was not attributable to impaired novelty detection. These data also suggest that at least some of the neurocognitive abnormalities caused by chronic MA administration may normalize after prolonged abstinence, since the ability to detect novelty recovered after 30 days of abstinence. These data provide compelling support that, since MA-sensitization caused temporal deficits in memory, PFC and HC function may be differentially impaired throughout the time course of abstinence.
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