Correlation between drug use by teenagers and drug use by older family members

This study examines the relationship between drug use by teenagers and older family members living in the same household, using data from the National Survey on Drug Abuse. Drug use by teenagers was found to be correlated with drug use by fathers, mothers, and older siblings, in that teenagers were more likely to be drug users if the older adult was also a drug user. Correlations were significant across different drug types, but the most consistent relationship was between marijuana use by youth and marijuana use by the adult.     

A latent class analysis of alcohol and drug use immediately before or during sex among women

Background: Alcohol and drug use by women is related to high-risk sexual practices and protective behaviors. Objectives: To determine sexual risk and protective behaviors using information about women’s drug use immediately before or during sex. Methods: Latent class analysis using PROC LCA in SAS software was used to determine classes of women using both past 30-day drug use and before or during sex. Participants were recruited from a community-based research site located in a low socio-economic area of Los Angeles County and completed the Risk Behavior Assessment, which elicits information on drug and sex risk behaviors. Results: The Risk Behavior Assessment and HIV and sexually transmitted infections testing was obtained on 812 women. Five distinct groups were identified by PROC LCA: An Abstinent group comprised of 26% of participants; an Alcohol and Marijuana group (16%); an Amphetamine group (11%); a No Sex-with-Alcohol group (37%); and a Poly Drug group (11%). Multinomial logistic regression revealed that sexual behaviors and condom use were different across the five groups: The Alcohol and Marijuana group had a higher odds of vaginal intercourse, while the No Sex-with-Alcohol group was most likely to use condoms for vaginal intercourse. The Poly Drug group had the highest risk for anal intercourse while the Amphetamine and Poly Drug groups had high proportions of women with injection-drug using and men-who-have-sex-with-men sexual partners. Conclusion: Identifying women based on drug use immediately before or during sex can help providers understand prevention and risk-reduction practices and interventions for drug-using women.     

Testing theoretical network classes and HIV-related correlates with latent class analysis

Scientists designing network-based interventions intending to improve the adoption or maintenance of healthy behaviors are well-advised to classify potential adopters into network roles, such as opinion leaders, brokers, members, and isolates, and to work closely with existing opinion leaders. In past studies focusing on HIV, opinion-leader interventions have had mixed results. This may be addressed, in part, by empirically validating these network roles. To this end, we used latent class analysis to test whether people's social connections fall into mutually exclusive and exhaustive subgroups of social capital that represent theorized network roles well with a dataset collected in Nyangana, Namibia (n = 400). A four-class model best fits the dataset, but the categories identified do not clearly represent the theorized roles. Rather, this study revealed the following four network classes: single-group members (59%), connectors (24%), single-group loyalists (15%), and selective connectors (2%). The implications of their findings for opinion-leader interventions focused on HIV are discussed.     

Comparative drug use and psychosocial profiles of opioid dependents applying for medication versus medication-free treatment

Drug treatment-seeking abusers generally self-select their treatment modality. Most opioid-dependent individuals select either methadone maintenance or detoxification followed by medication-free outpatient treatment. This study examined demographic, drug use, and drug abuse treatment history for opioid dependent patients entering an opioid agonist (n = 203) or a medication-free (n = 155) treatment program located on the same hospital campus. Similar demographic profiles support the assertion that samples were drawn from the same inner city urban opioid using population. Patients entering drug-free treatment, however, reported more extensive prior use of both cocaine and alcohol. Further, these patients had a generally more severe profile of psychosocial problems in medical, legal, employment, family/social, and psychiatric areas as measured by the Addiction Severity Index (ASI). These findings suggest that outpatient drug-free programs enrolling opioid abusers are faced with a unique service delivery challenge that involves service needs in multiple arenas. The findings further suggest that patient self-selection of treatment programs may in some cases result in a discrepancy between patient needs and the ability of treatment programs to retain patients and deliver an appropriate array of services.     

Adjunctive drug use by methadone patients.

Clinical impressions, reinforced by reports in both professional journals and the lay press, suggested that use and abuse of minor tranquilizers and sedative-hypnotics was extensive among patients in our drug treatment clinics and required some change in our policies. We surveyed a randomly selected national sample of methadone program physicians and found they shared our assumptions concerning the use of these drugs. A pilot program of urine screening for the presence of adjunctive drugs was completed, and we found the incidence of use to be below expected levels, except for opiates and alcohol. These results suggest we should reconsider plans to alter clinic policies concerning the regulation of these substances. A rigorous examination of serum and/or urine in a national research program to determine both the incidence of adjunctive drug use by clients in drug treatment programs and correlations of such data with national surveys would be an expensive undertaking, but would provide a more rational basis for policy making at both local and national levels.     

Cognitive performance by humans during a smoked cocaine binge-abstinence cycle

Five cocaine-dependent individuals completed a 22-day inpatient study of sleep and cognition. Following 3 days of drug-free baseline, participants underwent 3 days of twice-daily smoked cocaine base self-administration (6 50-mg doses, 14 minutes apart), followed by 15 days of abstinence. Each morning and afternoon, the CDR repeatable, multiple-version, computerized cognitive battery (whose stability following practice has been documented) was administered. During abstinence, performance deteriorated on vigilance tasks (especially reaction time) as well as on immediate and delayed verbal recognition tasks but not on working memory tasks. Declines were most evident in the afternoon. Data suggest that abstinence can unmask cognitive deficits induced by chronic cocaine use and circadian factors may mediate their severity.     

Integrating person-centered and variable-centered analyses: growth mixture modeling with latent trajectory classes

BACKGROUND: Many alcohol research questions require methods that take a person-centered approach because the interest is in finding heterogeneous groups of individuals, such as those who are susceptible to alcohol dependence and those who are not. A person-centered focus also is useful with longitudinal data to represent heterogeneity in developmental trajectories. In alcohol, drug, and mental health research the recognition of heterogeneity has led to theories of multiple developmental pathways. METHODS: This paper gives a brief overview of new methods that integrate variable- and person-centered analyses. Methods discussed include latent class analysis, latent transition analysis, latent class growth analysis, growth mixture modeling, and general growth mixture modeling. These methods are presented in a general latent variable modeling framework that expands traditional latent variable modeling by including not only continuous latent variables but also categorical latent variables. RESULTS: Four examples that use the National Longitudinal Survey of Youth (NLSY) data are presented to illustrate latent class analysis, latent class growth analysis, growth mixture modeling, and general growth mixture modeling. Latent class analysis of antisocial behavior found four classes. Four heavy drinking trajectory classes were found. The relationship between the latent classes and background variables and consequences was studied. CONCLUSIONS: Person-centered and variable-centered analyses typically have been seen as different activities that use different types of models and software. This paper gives a brief overview of new methods that integrate variable- and person-centered analyses. The general framework makes it possible to combine these models and to study new models serving as a stimulus for asking research questions that have both person- and variable-centered aspects.     

The heterogeneous health latent classes of elderly people and their socio-demographic characteristics in Taiwan

The health care needs of elderly people were influenced by their heterogeneity. This study aimed to identify the health latent classes of elderly people by using latent class analysis to deal with heterogeneity and examine their socio-demographic characteristics. Data came from the 2005 National Health Interview Survey (NHIS) in Taiwan. In total, 2449 elderly individuals with available health indicators were examined in latent class analysis (LCA), and 2217 elderly community-dwellings with complete socio-demographic data were analyzed by multinomial logistic regression. Four health latent classes were identified which included 1066 (43.5%) people in the High Comorbidity (HC), 152 (6.2%) in the Functional Impairment (FI), 252 (10.3%) in the Frail (FR), and 979 (40.0%) in the Relatively Healthy (RH) group. Multinomial logistic regressions revealed socio-demographic characteristics among health classes. The variables associated with an increased likelihood of being in the FR group were age, female, and living with families. They were also correlated to ethnicity and educations. Apart from age and gender, the Functional Impairment group was less likely to be ethnicity of Hakka, more likely to live with others than were the RH group. The HC group tended to be younger, with higher educations, and more likely to live in urban area than the Functional Impairment group. The correlations between health classes and socio-demographic factors were discussed. The health status of elderly people includes a variety of health indicators. A person-centered approach is critical to identify the health heterogeneity of elderly people and manage their care needs by targeting differential aging.     

Cognitive processes in adolescent drug use: the role of positivity bias and implications for prevention policy

Recent investigations of the role of expectations about the effects of alcohol in drinking behavior suggest that there is a functional relationship between expectancies and alcohol use. Specifically, greater positive expectancies are related to heavier drinking patterns. In contrast, expectations about the negative consequences of alcohol use seem to be unrelated to drinking behavior. These differential roles of positive and negative expectancies as mediators of alcohol use reflect the robust phenomenon of positivity bias in human information processing. The theoretical and clinical implications of this phenomenon with respect to adolescent drug use are discussed.     

Youthful drug use and drug subcultures

Drug involvement is such an intensely social behavior that it lends itself to the notion of a subcultural existence. The social aspects of drug involvement generate a value system that is different from the dominant order. Using a longitudinal sample of college students, the findings indicate two distinctively different types of drug use, marijuana-only versus illicit drug involvement, that correspond to a subcultural or contracultural phenomenon. The elements of a subculture or contraculture are amenable to empirical measurement and can be differentiated from the dominant value system. Marijuana use reflects a type of subculture activity that maintains ties to the conventional order. Illicit drug use, on the other hand, is a contracultural activity, representing a pronounced break with the dominant culture.     

Effect of different antihypertensive drug classes on central aortic pressure

Central aortic systolic blood pressure (BP) is an important determinant of cardiac workload and cardiac hypertrophy. The relationship of central aortic systolic BP and brachial BP varies depending on the stiffness of blood vessels. It is not certain whether the different drug classes affect the brachial and aortic systolic BP in a similar manner.In a double-blind crossover study, we measured the effects of the four major drug classes compared with placebo on central aortic pressure. Central aortic pressure and various indices were determined using the Sphygmo Cor apparatus. The study was undertaken in patients aged 65 to 85 years with systolic BP >150 mm Hg at study entry. Results are reported for 32 patients who had satisfactory applanation tonometry in all five periods.Calcium channel blockers and diuretics caused a greater fall in brachial artery systolic BP than angiotensin-converting enzyme (ACE) inhibitors or beta-blocking drugs. On placebo, central aorta augmentation pressure and index were 23 mm Hg and 33.3%; on ACE inhibitors the values were 18 mm Hg and 30%; on beta-blockers, 26 mm Hg and 38.5%; on calcium channel blockers, 16 mm Hg and 28%; and on diuretics, 17 mm Hg and 28.8%. The augmentation pressure on beta-blocking drugs was greater than on the other three drug classes (P <.05), and augmentation pressures on ACE inhibitors, calcium channel blockers, and diuretics were less than on placebo (P <.05). The lowest central aortic pressures were achieved with calcium blocking drugs and diuretics.Therapy based on brachial artery recordings may thus overestimate the effect of beta-blocking drugs on central aortic systolic BP and underestimate the effectiveness of ACE inhibitors and calcium blocking drugs. The clinical importance of this discrepancy needs to be evaluated.     

Cognitive performance in patients with COPD

BACKGROUND: Hypoxemic patients with Chronic Obstructive Pulmonary Disease (COPD) have impaired cognitive performance. These neuropsychological impairments are related to the degree of hypoxemia. So far, cognitive performance has not been tested in non-hypoxemic patients with COPD. METHODS: We recruited patients with stable COPD and PaO2 > 8.0 kPa (60 mmHg), as well as healthy subjects, who were matched for age, intelligence quotient (IQ), and level of education. Cognitive performance was studied by Stroop Colour Word Test, Trailmaking, digit-symbol of the Wechsler Adult Intelligence Scale, addition subtest of the Groningen Intelligence Test, and Story Recall. RESULTS: Thirty patients with COPD (FEV1 49.8% pred, mean age 64.8 yr) and 20 healthy volunteers (65.6 yr) were enrolled. COPD patients performed significantly worse on trailmaking B, the digit-symbol test, and on the addition subtest. There was no significant correlation between the tests of cognitive performance and disease specific health status (Chronic Respiratory Questionnaire). CONCLUSIONS: We conclude that even non-hypoxemic patients with COPD show significant impairments in cognitive performance. These impairments are not associated with deteriorations in health related quality of life. Prospective evaluation of the impact of treatment on cognitive performance in non-hypoxemic patients with COPD would be a logical subsequent study.