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BACKGROUND: Alcohol and marijuana are the two most abused substances in US colleges. However, research on the combined influence (cross sectional or longitudinal) of these substances on academic performance is currently scant. METHODS: Data were derived from the longitudinal 2-year Brain and Alcohol Research in College Students (BARCS) study including 1142 freshman students who completed monthly marijuana use and alcohol consumption surveys. Subjects were classified into data-driven groups based on their alcohol and marijuana consumption. A linear mixed-model (LMM) was employed using this grouping factor to predict grade point average (GPA), adjusted for a variety of socio-demographic and clinical factors. RESULTS: Three data-driven clusters emerged: 1) No/low users of both, 2) medium-high alcohol/no-low marijuana, and 3) medium-high users of both substances. Individual cluster derivations between consecutive semesters remained stable. No significant interaction between clusters and semester (time) was noted. Post-hoc analysis suggest that at the outset, compared to sober peers, students using moderate to high levels of alcohol and low marijuana demonstrate lower GPAs, but this difference becomes non-significant over time. In contrast, students consuming both substances at moderate-to-high levels score significantly lower at both the outset and across the 2-year investigation period. Our follow-up analysis also indicate that when students curtailed their substance use over time they had significantly higher academic GPA compared to those who remained stable in their substance use patterns over the two year period. CONCLUSIONS: Overall, our study validates and extends the current literature by providing important implications of concurrent alcohol and marijuana use on academic achievement in college.
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Logro , Consumo de Bebidas Alcohólicas , Fumar Marihuana , Estudiantes/estadística & datos numéricos , Adolescente , Ansiedad/patología , Análisis por Conglomerados , Depresión/patología , Femenino , Humanos , Modelos Lineales , Estudios Longitudinales , Masculino , Clase Social , Universidades , Adulto JovenRESUMEN
BACKGROUND: Identifying factors that modify responsiveness to pharmacotherapies for alcohol dependence is important for treatment planning. Cigarette smoking predicts more severe alcohol dependence and poorer treatment response in general. Nevertheless, there is limited research on cigarette smoking as a potential predictor of differential response to pharmacological treatment of alcoholism. METHODS: We examined the association between cigarette smoking and drinking outcomes in the COMBINE (Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence) study, a randomized, double-blind placebo-controlled 16-week trial comparing combinations of medications (i.e., acamprosate and naltrexone) and behavioral interventions (i.e., medical management, combined behavioral therapy) in 1383 alcohol-dependent individuals. RESULTS: Smokers (i.e., more than one half the sample) significantly differed from nonsmokers on several demographic and drinking-related variables at baseline and generally had poorer treatment outcomes than nonsmokers. However, smokers who received naltrexone had better drinking outcomes than smokers who received placebo, whereas alcohol use among nonsmokers did not vary by naltrexone assignment. This pattern of findings occurred independent of whether patients received combined behavioral intervention or medical management and remained after controlling for alcoholism typology and baseline demographic differences. Approximately 9% of smokers quit smoking, and an additional 10% reduced their cigarette intake during treatment. Reductions in smoking did not vary by treatment assignment. CONCLUSIONS: These results suggest that naltrexone might be particularly beneficial for improving alcohol use outcomes in alcohol-dependent smokers.
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Alcoholismo , Terapia Conductista/métodos , Naltrexona , Fumar , Taurina/análogos & derivados , Acamprosato , Adulto , Disuasivos de Alcohol/administración & dosificación , Disuasivos de Alcohol/farmacocinética , Alcoholismo/epidemiología , Alcoholismo/psicología , Alcoholismo/terapia , Terapia Combinada , Comorbilidad , Interacciones Farmacológicas , Quimioterapia Combinada/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Naltrexona/administración & dosificación , Naltrexona/farmacocinética , Antagonistas de Narcóticos/administración & dosificación , Antagonistas de Narcóticos/farmacocinética , Fumar/epidemiología , Fumar/psicología , Fumar/terapia , Taurina/administración & dosificación , Taurina/farmacocinética , Resultado del TratamientoRESUMEN
OBJECTIVE: Most previous studies of the incidence of tardive dyskinesia with atypical antipsychotics compared with conventional antipsychotics have not had tardive dyskinesia as their primary focus. The current study aimed to compare the incidence of tardive dyskinesia with atypical vs conventional antipsychotics using methods similar to those from a previous prospective cohort study at our site in the 1980s. METHOD: Three hundred fifty-two initially tardive dyskinesia-free psychiatric outpatients (diagnosed at baseline using the Structured Clinical Interview for DSM-IV) were examined for a new diagnosis of tardive dyskinesia (using the Abnormal Involuntary Movement Scale and Glazer-Morgenstern criteria) every 6 months for up to 4 years at a community mental health center. At baseline, subjects were receiving conventional antipsychotics only (23%), atypicals only (64%), or both (14%). Only 26 subjects had never received conventional antipsychotics. Baseline evaluations were conducted from November 2000 through May 2003. Follow-ups were conducted through February 2005. RESULTS: Compared with subjects treated with conventional antipsychotics alone since the previous visit, the adjusted tardive dyskinesia incidence rate-ratio for subjects treated with atypical antipsychotics alone was 0.68 (95% CI, 0.29-1.64). The incidence and prevalence of tardive dyskinesia was similar to previous findings at this site in the 1980s. CONCLUSIONS: The incidence of tardive dyskinesia with recent exposure to atypical antipsychotics alone was more similar to that for conventional antipsychotics than in most previous studies. Despite high penetration of atypical antipsychotics into clinical practice, the incidence and prevalence of tardive dyskinesia appeared relatively unchanged since the 1980s. Clinicians should continue to monitor for tardive dyskinesia, and researchers should continue to pursue efforts to treat or prevent it.
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Antipsicóticos/efectos adversos , Discinesia Inducida por Medicamentos/epidemiología , Adolescente , Adulto , Anciano , Atención Ambulatoria , Antipsicóticos/uso terapéutico , Estudios de Cohortes , Centros Comunitarios de Salud Mental , Connecticut/epidemiología , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Discinesia Inducida por Medicamentos/diagnóstico , Discinesia Inducida por Medicamentos/etiología , Femenino , Humanos , Incidencia , Estudios Longitudinales , Masculino , Trastornos Mentales/tratamiento farmacológico , Persona de Mediana Edad , Prevalencia , Estudios Prospectivos , Escalas de Valoración Psiquiátrica , Factores de Riesgo , Índice de Severidad de la EnfermedadRESUMEN
In longitudinal studies and in clustered situations often binary and continuous response variables are observed and need to be modeled together. In a recent publication Dunson, Chen, and Harry (2003, Biometrics 59, 521-530) (DCH) propose a Bayesian approach for joint modeling of cluster size and binary and continuous subunit-specific outcomes and illustrate this approach with a developmental toxicity data example. In this note we demonstrate how standard software (PROC NLMIXED in SAS) can be used to obtain maximum likelihood estimates in an alternative parameterization of the model with a single cluster-level factor considered by DCH for that example. We also suggest that a more general model with additional cluster-level random effects provides a better fit to the data set. An apparent discrepancy between the estimates obtained by DCH and the estimates obtained earlier by Catalano and Ryan (1992, Journal of the American Statistical Association 87, 651-658) is also resolved. The issue of bias in inferences concerning the dose effect when cluster size is ignored is discussed. The maximum-likelihood approach considered herein is applicable to general situations with multiple clustered or longitudinally measured outcomes of different type and does not require prior specification and extensive programming.
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Teorema de Bayes , Análisis por Conglomerados , Animales , Desarrollo Embrionario , Glicol de Etileno/metabolismo , Glicol de Etileno/toxicidad , Femenino , Ratones , Modelos Biológicos , Modelos Estadísticos , Embarazo , Programas InformáticosRESUMEN
CONTEXT: It has been suggested that the need for concurrent placebo control groups in new schizophrenia studies might be minimized by making comparisons with external placebo. This strategy requires an assumption of constancy, that the novel medication will perform the same way in a study with only active controls as it would have in a placebo-controlled trial. OBJECTIVE: To test this constancy assumption in active- and low dose-controlled trials vs placebo-controlled trials of atypical antipsychotic medications. DATA SOURCES: A comprehensive search of bibliographic databases, conference proceedings, and Food and Drug Administration databases through November 24, 2003. STUDY SELECTION: English-language, randomized, double-blind clinical trials of newer atypical antipsychotic medications in otherwise unselected acutely ill adults with schizophrenia or schizoaffective disorder that reported baseline and intent-to-treat end point change values for the Brief Psychiatric Rating Scale. DATA EXTRACTION: Study number, sample size, reported dosage for each arm, trial duration, percentage of men, average age, trial arm treatment completion rate, baseline and within-arm end point change in the Brief Psychiatric Rating Scale, method of scoring the Brief Psychiatric Rating Scale, and date of publication were extracted from each study independently by 2 of us (S.W.W. and C.B.B.) each. DATA SYNTHESIS: There were 32 studies comprising 66 risperidone, olanzapine, quetiapine, and ziprasidone arms including 7264 patients. Random-effects analysis revealed that in atypical antipsychotic medication arms, the degree of improvement was nearly double in active-controlled trials than that seen with the same drugs and dosages in placebo-controlled studies. An effect of design was also observed in low dose-controlled studies vs placebo-controlled studies in ineffective and intermediate antipsychotic medication dose ranges. CONCLUSIONS: The observed control group bias indicates that the constancy assumption does not hold in recent antipsychotic medication trials. These results suggest that caution is indicated when considering active- or low dose-controlled studies requiring comparisons with external placebo as alternatives to placebo-controlled trials for establishing efficacy of new medications for schizophrenia.
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Antipsicóticos/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Esquizofrenia/tratamiento farmacológico , Sesgo de Selección , Factores de Edad , Escalas de Valoración Psiquiátrica Breve/estadística & datos numéricos , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Masculino , Placebos , Trastornos Psicóticos/tratamiento farmacológico , Trastornos Psicóticos/psicología , Ensayos Clínicos Controlados Aleatorios como Asunto/normas , Proyectos de Investigación/normas , Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Índice de Severidad de la Enfermedad , Factores Sexuales , Resultado del TratamientoRESUMEN
OBJECTIVES: To develop a risk-assessment screening tool for very low birth weight (VLBW) and to compare our empirically derived tool to the nonempirically derived screening tool used by the State of Florida. METHODS: Birth records from the State of Florida Vital Statistics between 04/01/92 and 12/07/94 were matched with State Healthy Start prenatal records, reported from 04/01/92 through 03/31/94. Known and additional potentially important risk factors were identified from both sources. Generalized Linear Modeling techniques were used to estimate associations between risk factors and VLBW. A risk assessment system was then developed using the estimated model. The resulting screening test was compared with the one used by the Florida State Department of Health in terms of sensitivity and specificity on an independent validation sample. RESULTS: The proposed screening tool had comparable specificity to the Healthy Start screening tool but significantly better sensitivity. Both instruments are simple and easy to implement. CONCLUSIONS: Identification of women at high risk for VLBW would be improved using the model-based screening tool developed in this paper. Public health policy makers should use statistical methods in addition to expert opinion to improve existing risk assessment methods. The actual value of an improved screening instrument is dependent on the availability of effective intervention programs.