Essays on the Economics of Drug Abuse

This dissertation consists of three essays on substance abuse. The first essay examines whether restricting access to legal prescription opioids has an impact on substance abuse behavior. Following the increase in people taking hydrocodone combination products (HCPs) in dangerous amounts, the Drug Enforcement Administration (DEA) requested the Department of Health and Human Services (DHHS) to conduct thorough research on HCPs. After evaluating the medical evidence, the DHHS recommended that all HCPs be transferred from a Schedule III to a Schedule II controlled substance. In 2014, the Drug Enforcement Administration (DEA) implemented the rescheduling of HCPs. The total number of HCPs prescriptions in the U.S fell from 136.7 million in 2013 to 83.6 million in 2017. Subsequently, the number of persons misusing HCPs also declined from 7.2 million in 2015 to about 5.5 million in 2018 (National Survey on Drug Use and Health, 2020). Using data from the 2005 to 2019 Treatment Episode Data Set (TEDS) survey, I analyze the effect of the policy on substance abuse behavior. I employ a difference-in-differences strategy that explores the cross-state variation in the pre-implementation hydrocodone prescription rate. I find evidence that suggests that the rescheduling led to a reduction in the utilization of hydrocodone combination medications. Given this evidence of a first-stage effect, I also assess whether the decline in legally-obtained opioid prescriptions affects the misuse of other substances. I find that a one percentage point increase in the mean hydrocodone prescription (i.e., 13kg per 100,000 residents) increases alcohol abuse treatments by 63 treatments per 100,000 adults, marijuana abuse treatments by 40 treatments per 100,000 adults, and cocaine abuse treatments by 13.2 treatments per 100,000 adults. The second essay investigates whether the rescheduling of HCPs could potentially have a spillover effect on crime. By reducing the supply of HCPs through the rescheduling, the policy may have had an unintended consequence on the cost of obtaining illegal prescription opioids. To explore this question, I use arrest data from 2006 to 2019 from the Uniform Crime Reporting (UCR) program provided by the Federal Bureau of Investigation (FBI) combined with a difference-in-differences strategy. I find evidence that the rescheduling of HCPs led to an increase in violent crimes. I estimate that violent crimes increased by 23.9 offenses per 100,000. The increase in violent crimes is driven by an increase in aggravated assault crimes. The final essay in my dissertation investigates the impact of the Affordable Care Act\u27s (ACAs) Medicaid expansion on the access and the utilization of substance use disorder (SUD) treatment. After the implementation of the Affordable Care Act, individuals with SUD have greater access to treatment through various programs and policy changes. To estimate the effect of the policy, I exploit the variation in the timing of the Medicaid expansion across states. I find that the ACA\u27s Medicaid expansion led to a 36% decrease in the number of uninsured substance abuse patients and a 90% increase in Medicaid insurance coverage among the same group. Following the gains in insurance coverage among substance abuse patients, one would expect an increase in the utilization of substance abuse treatment. I measure the utilization of substance abuse treatment using the number of admissions per 100,000 non-elderly adults and treatment completion status. The results show that the ACA\u27s Medicaid expansion had no statistically significant effect on substance abuse treatment admissions. A potential explanation for this is that access to health insurance coverage alone may not impose a substantial barrier to seeking substance abuse treatment

Double Plurality in Codeswitching

This paper deals with the phenomenon of double plurality in codeswitching, with illustrations from Ewe-English Codeswitching (CS). It shows that English nouns (but never Ewe ones) may take two plurals, the English -s and its Ewe counterpart wó. -s always occurs on the stem of the noun while wó occurs either immediately after -s or a few slots away. The paper demonstrates that.the English noun-and-plural units are consistently embedded in Ewe-based NPs in which Ewe modifiers of the English nouns occur in slots associated with them in monolingual Ewe NPs. While -s may be dropped from mixed NPs that already show double plurality, the dropping of wó from such NPs makes them unacceptable. Three theoretical questions are asked in our quest to explain this plural doubling phenomenon. One is why it involves only English noun heads. The second relates to why the two forms emerge as plurals even though -s is redundant. The third one is about the nature of language production involved: what bilingual processes are involved in the phenomenon of double plurality? It is shown that the two plurals arrive in their respective positions in the mixed NPs via separate paths in language production. The distribution of -s relates to processes that are conceptual (i.e. semantic-pragmatic) in nature. On the other hand, the distribution of wó relates to processes that are morpho-syntactic in nature. Another issue briefly explored is what this bilingual phenomenon reveals about the linguistic properties of the plural category in monolingual NPs. The paper ends with a discussion of the role that language typology plays in determining whether plurals may be doubled or not doubled in CS

Localized Method of Approximate Particular Solutions for Solving Fourth-Order PDEs

In the past, dealing with fourth-order partial differential equations using the Local Method was not reliable due to difficulties in solving them directly. An approach such as splitting these equations into two Poisson differential equations was adopted to alleviate such challenges. However, this has a limitation since it is only applicable to Dirichlet and Laplace boundary conditions. In this paper, we solve fourth-order PDEs directly using the LMAPS. The improvement on the accuracy of this method was as a result of the proposed distribution of boundary conditions to alternating boundary points. And, also the use of suitable shape parameter; calculated using LOOCV(Leave-One-Out-Cross-Validation) Algorithm. The effectiveness of this Method was evident when we compared the results from two numerical examples

Socio-pragmatics of conversational codeswitching in Ghana

The purpose of this paper is to deepen insight into the socio-pragmatics of conversational codeswitching in Ghana. It presents detailed textual analyses of the codeswitching that Ewe-English and Akan-English bilinguals employ in various social contexts, including informal interactions at home, semi-formal discussions in study group meetings at school, and interactions on talk-radio. We find that codeswitching appears to be predominantly unmarked (i.e. that it appears to fulfil little or no pragmatic and discursive functions in interactions beyond indexing speakers’ solidarity). But upon closer look we realize that many codeswitching instances that could pass as unmarked are in fact illustrations of marked codeswitching, which bilinguals employ stylistically to convey specifiable social and discourse intentions. The paper situates the discussion within an ongoing debate about the future of indigenous Ghanaian languages in intensive codeswitching contact with English. It specifically takes on the speculation that most of the local languages in this kind of contact will sooner rather than later transform into mixed codes. On the basis of the data analysed, the paper predicts instead that Ghanaians will manage to slow down any ongoing development of their languages into mixed codes if they continue to use marked codeswitching they way they do now. The prediction stems from the fact that bilinguals like them who use marked codeswitching alongside unmarked codeswitching normally have the mental capacity to keep their languages apart as codes with separate identities

The association between graded physical activity in postmenopausal British women, and the prevalence and incidence of hip and wrist fractures.

BACKGROUND: physical activity is promoted for older women as a means of maintaining health and avoiding falls and fractures. Findings relating physical activity of older women to risk of falls and fracture are contradictory. The association between level of physical activity and prevalent and incident hip and wrist fractures was examined in a large representative sample of postmenopausal British women. METHODS: data from the British Women's Heart and Health Study, a cohort study of 4286 postmenopausal women aged 60-79, from 23 UK towns were used. Information on physical activity, anthropometry, falls and hip and wrist fractures from baseline examination and questionnaire (1999-2001) and follow-up questionnaire (2007) were available. Cross-sectional baseline prevalence data were analysed using logistic regression and cohort incidence data using a Cox proportional hazards model examining the association of physical activity with fracture outcomes. RESULTS: 3003 (70%) women, with complete baseline data, were studied. 13.6% had previously fractured a wrist and 1.3% a hip. Analyses unadjusted for confounders showed moderate protective associations between activity and fracture risk. After adjustment for confounders there was a weak trend towards fewer hip fractures (adjusted OR 0.13 [0.01, 1.18]) and more wrist fractures (adjusted OR 1.35 [0.76, 2.48]), amongst most active compared with inactive women. The crude incidence rate of wrist and/or hip fracture was 7.0 [5.9, 8.2] per 1000 person-years. No evidence was found for an association between physical activity and combined incident hip and/or wrist fracture (adjusted rate ratio inactive versus most active 1.69 [0.67, 4.24]). CONCLUSION: no clear associations between graded physical activity and hip/wrist fractures were seen but estimates were imprecise. Physical activities are heterogeneous and individual fracture types and mechanisms differ. Very large prospective observational studies are required to disentangle the precise effects of different activity patterns on different fracture types

Survival with Treated and Well-Controlled Blood Pressure: Findings from a Prospective Cohort Study.

AIM: To compare survival and incident cardiovascular disease between normotensive, untreated hypertensive, treated and poorly-controlled hypertensive and treated and well-controlled hypertensive adults. METHODS AND RESULTS: Data from the British Regional Heart Study (men) and British Women's Heart and Health Study (women) were used (N = 6476). Blood pressure and treatment were assessed at baseline (1998-2001) when participants were aged 60-79 years and participants were followed up for a median of 8 years. Date and cause of death were obtained from death certificates and non-fatal cardiovascular disease events were obtained from repeat detailed medical record reviews. Of the whole cohort 52% of women and 49% of men had untreated hypertension and a further 22% and 18%, respectively, had poorly treated hypertension. Just 3% of women and 4% of men had treated and well controlled hypertension and 23% and 29%, respectively, were normotensive. Compared to normotensive individuals, incident cardiovascular disease (fatal and non-fatal) was increased in those with poorly-controlled hypertension (Hazard Ratio (HR): 1.88; 95%CI: 1.53, 2.30), those with untreated hypertension (HR 1.46; 95%CI 1.22, 1.75) and those who were well-controlled hypertension (HR 1.38; 95%CI 0.94, 2.03). Adjustment for baseline differences in mean blood pressure between the groups resulted in attenuation of the increased risk in the poorly-controlled (1.52 (1.18, 1.97) and untreated groups (1.21 (0.97, 1.52), but did not change the association in the well-controlled group. All-cause mortality was also increased in all three hypertension groups but estimates were imprecise with wide confidence intervals. CONCLUSIONS: Half of women and men aged 60-79 in Britain had untreated hypertension and only a very small proportion of those with diagnosed and treated hypertension were well controlled. Those with hypertension, irrespective of whether this was treated and controlled or not, were at greater risk of future cardiovascular disease than those who are normotensive

Second Language Learners’ Family Background and Their English Writing Competence: The Case of a Private Tertiary Institution in Ghana

This work assesses the effects of family background of second language learners on their academic writing competence in English. A cursory study of some examination scripts of first-year students reveals some poor writing skills of students in areas such as concord, spelling, capitalization, and fragmentation errors.30 participants were selected from a class of 121 students from the Ghana Baptist University College, a private institution in Kumasi, Ghana. Initially, the class of 121 was sorted out into three groups—those who said they used only English at home, those who said they used only Ghanaian language(s) at home, and those who said they used both English and Ghanaian language(s) at home. Each group was further divided along gender lines and 5 students from each of the 6 sub-groups were picked randomly. The participants were then made to write a sit-in assessment on a topic and were graded by an independent assessor. The findings of the study reveal that the performance of the bilingual English and Ghanaian language learners outweighed those of their contemporaries. The study also revealed a positive correlation between attitudes of parents about English and learners’ academic writing skills. These have pedagogical and theoretical implications for the teaching and learning of English as a second language in Ghana. Language proficiency involves the development of skills in listening, speaking, reading, and writing. All these four aspects of language development are equally vital in the language learning process, but the current paper focuses on the development of writing skills by second language learners of English in Ghana

Effect of changes in moderate or vigorous physical activity on changes in health-related quality of life of elderly British women over seven years.

PURPOSE: This study investigates the effect of changes in moderate or vigorous physical activity (MVPA) on trajectories in health-related quality of life (HR-QoL) over 7 years in British elderly women. METHODS: A total of 1,926 women from the British Women's Heart and Health Study with information on MVPA and HR-QoL [measured using Euro quality of life 5 dimension (EQ-5D)] at baseline and at 7 years of follow-up were included in the analysis. Baseline and 7-year follow-up MVPA values were categorised into 3 groups, generating 9 categories of change in MVPA. Logistic regression was used to obtain odds ratios (ORs) of maintaining or improving HR-QoL according to different patterns of change in MVPA level. RESULTS: Women who remained inactive over the 7 years of follow-up had the largest reduction in their EQ-5D scores. Compared to these women, women that increased their MPVA level from "inactive" to "low" or to "moderate-high" were more likely to maintain or improve their HR-QoL over 7 years (ORs 1.65 or 2.70, respectively, p value for trend <0.001). After adjustment for baseline EQ-5D score and a wide range of potential confounders, results remained largely unchanged, though precision of the estimates generally decreased. CONCLUSIONS: Our findings suggest that relatively regular MVPA, even taken up later in life, can help older women prevent a decline in HR-QoL and even improve their enjoyment of life

Effect of changes in moderate or vigorous physical activity on changes in health-related quality of life of elderly British women over seven years.

PURPOSE: This study investigates the effect of changes in moderate or vigorous physical activity (MVPA) on trajectories in health-related quality of life (HR-QoL) over 7 years in British elderly women. METHODS: A total of 1,926 women from the British Women's Heart and Health Study with information on MVPA and HR-QoL [measured using Euro quality of life 5 dimension (EQ-5D)] at baseline and at 7 years of follow-up were included in the analysis. Baseline and 7-year follow-up MVPA values were categorised into 3 groups, generating 9 categories of change in MVPA. Logistic regression was used to obtain odds ratios (ORs) of maintaining or improving HR-QoL according to different patterns of change in MVPA level. RESULTS: Women who remained inactive over the 7 years of follow-up had the largest reduction in their EQ-5D scores. Compared to these women, women that increased their MPVA level from "inactive" to "low" or to "moderate-high" were more likely to maintain or improve their HR-QoL over 7 years (ORs 1.65 or 2.70, respectively, p value for trend <0.001). After adjustment for baseline EQ-5D score and a wide range of potential confounders, results remained largely unchanged, though precision of the estimates generally decreased. CONCLUSIONS: Our findings suggest that relatively regular MVPA, even taken up later in life, can help older women prevent a decline in HR-QoL and even improve their enjoyment of life