Micro-ultrasound based characterization of cerebrovasculature following focal ischemic stroke and upon short-term rehabilitation

Notwithstanding recanalization treatments in the acute stage of stroke, many survivors suffer long-term impairments. Physical rehabilitation is the only widely available strategy for chronic-stage recovery, but its optimization is hindered by limited understanding of its effects on brain structure and function. Using micro-ultrasound, behavioral testing, and electrophysiology, we investigated the impact of skilled reaching rehabilitation on cerebral hemodynamics, motor function, and neuronal activity in a rat model of focal ischemic stroke. A 50 MHz micro-ultrasound transducer and intracortical electrophysiology were utilized to characterize neurovascular changes three weeks following focal ischemia elicited by endothelin-1 injection into the sensorimotor cortex. Sprague-Dawley rats were rehabilitated through tray reaching, and their fine skilled reaching was assessed via the Montoya staircase. Focal ischemia led to a sustained deficit in forelimb reaching; and increased tortuosity of the penetrating vessels in the perilesional cortex; with no lateralization of spontaneous neuronal activity. Rehabilitation improved skilled reaching; decreased cortical vascularity; was associated with elevated peri- vs. contralesional hypercapnia-induced flow homogenization and increased perilesional spontaneous cortical neuronal activity. Our study demonstrated neurovascular plasticity accompanying rehabilitation-elicited functional recovery in the subacute stage following stroke, and multiple micro-ultrasound-based markers of cerebrovascular structure and function modified in recovery from ischemia and upon rehabilitation.

MRI and the brain in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) can affect any part of the central nervous system (CNS) from the cerebrum to the cauda eqina, giving rise to diverse neurological mainfestations. Despite clinically apparent symptoms and signs, imaging will commonly be normal while at times the magnitude of changesdemonstratedon MRI may be out of proportionto the clinical presentation.We describethe MRI techniques used in CNS imaging and the pattern of presentation in SLE.

Preventing alcohol-related harm in college students: Alcohol-related Harm Prevention program effects on hypothesized mediating variables

The Alcohol-related Harm Prevention (AHP) program is a normative education and skill-acquisition program designed to reduce serious, long-term alcohol-related harm in college students. Without admonishing students not to drink, which is likely to fail in many student populations, the AHP program attempts to give students the necessary perceptions, motivation and skills to intervene within their peer group, and to make proactive harm-avoidance plans with friends prior to social occasions that involve using alcohol. The AHP program is a two-session, in-class intervention that corrects misperceived norms regarding levels of alcohol use, caring about friends, acceptability of risky behaviors and willingness to intervene. The program also makes use of interactive discussions with students and a graded, peer interview assignment to identify and promote harm-prevention strategies. The AHP program was implemented during fall 1999 at a large northeastern university. The program was received very well by students and showed significant effects on the proximal outcomes hypothesized to mediate more distal health-relevant outcomes.

Childhood risk factors for persistence of violence in the transition to adulthood: a social development perspective

This study examined violent behavior from ages 13 to 21 and identified predictors at age 10. Logistic regression was used to assess predictors of developmental patterns of violence. The sample is from a study of 808 youth interviewed annually from age 10 to 16 years, and again at ages 18 and 21. Over 28% of the youth in the sample reported nonviolence throughout adolescence and into early adulthood. Most youth (55%) engaged in violence in adolescence but desisted from violence in early adulthood, while 16% persisted in violent behavior at age 21. Violence in adolescence was best predicted by male gender, Asian American ethnicity (a protective factor), childhood fighting, early individual characteristics, and early antisocial influences. Adult persistence of violence was best predicted by male gender, early school achievement (which was protective), and early antisocial influences. Early prosocial development was also protective against violence persistence for females. Implications for prevention are discussed.

Verifying drug abuse prevention program effects using reciprocal best friend reports

Considerable research suggests that social influences-based drug abuse prevention programming has produced the most consistently successful preventive effects. However, a common criticism of this literature is that most prevention intervention studies rely solely on self-reported substance use. The purpose of this study was to assess the effects of normative education, arguably the most successful component of social influence based prevention programs, on alcohol and cigarette consumption using both self- and reciprocal best friend reports of substance use. Analyses of subsamples of data from 11,995 students participating in the Adolescent Alcohol Prevention Trial revealed that normative education significantly delayed the onset of alcohol use across the eighth, ninth, and tenth grades among public school students. A similar but somewhat less robust pattern was found for cigarette use. These results suggest that self-report bias does not account for previous findings and demonstrate rather convincingly that normative education is an effective drug prevention strategy for public school settings.

Modeling prevention program effects on growth in substance use: analysis of five years of data from the Adolescent Alcohol Prevention Trial

The efficacy of prevention programs is typically determined through analysis of covariance. To date, a growth curve modeling approach is not used extensively in program evaluation. However, for longitudinal data there are several advantages to using this approach as compared to methods comparing means at two time points in a piecemeal fashion. In this study, latent growth curve models were used to evaluate the effect of a program on the average level of drug use, rate of change (growth) of drug use, and acceleration or deceleration in the rate of change of drug use. The study relied on data from the Adolescent Alcohol Prevention Trial, a randomized longitudinal drug use prevention program. The program consists of drug use information, resistance skills training, and normative education components. Data regarding cigarette and alcohol use were collected over a 5-year period, grade 7 to grade 11. Students receiving the normative education program had significantly lower average levels of reported cigarette and alcohol use, lower rates of growth for reported cigarette and alcohol use, and less deceleration of reported levels of cigarette and alcohol use as compared with the control group. Growth curve analysis is a powerful and effective tool with which to model change and program efficacy.

Perceived exposure to peer and adult drinking as predictors of growth in positive alcohol expectancies during adolescence

This study investigated the effects of change in exposure to peer and adult drinking on changes in positive alcohol expectancies during adolescence. Covariance and mean structure analysis were used to model change in the predictors and in alcohol expectancies in a sample of southern California schoolchildren followed from Grades 5 to 10 (N = 3,580). The sample was gender balanced and was predominantly White (51%) and Hispanic (28%). Exposure to peer drinking and rate of change in exposure to peer and adult drinking were found to predict the rate of change in alcohol expectancies. These effects were particularly strong between Grades 5 and 7, suggesting the need for early intervention aimed to prevent the increase in positive alcohol expectancies.

Applying multilevel analytic strategies in adolescent substance use prevention research

BACKGROUND

School-based drug prevention programs have been criticized on methodologic grounds because the unit of analysis is often not the unit of randomization, thus increasing the likelihood of Type I errors. Application of multilevel analytic strategies appropriately corrects this biasing tendency. This study demonstrates the practical use of such analysis.

METHODS

Data from 2,370 seventh-grade students participating in a substance use prevention trial were analyzed using a multilevel strategy. We examined the effectiveness of a social pressure resistance training and a normative education (NORM) intervention against an information-only control group.

RESULTS

The NORM condition revealed 1-year program effects for cigarette and marijuana use with individuals as the unit of analysis and only marginal effects with classroom as the unit of analysis. No program effects were found using school as the analysis unit. A multilevel strategy revealed program effects for cigarettes and marijuana with both class and school as grouping levels. The effect for alcohol use was significant at the 2-year follow-up.

CONCLUSIONS

Interventions establishing conservative drug use norms in classrooms may be an effective strategy in reducing substance use onset among adolescents. Utilization of appropriate analytic strategies is important in the analysis and interpretation of data containing nested structures.

Exploring the effects of age of alcohol use initiation and psychosocial risk factors on subsequent alcohol misuse

OBJECTIVE

This study examines whether the age of initiation of alcohol use mediates the effects of other variables that predict alcohol misuse among adolescents and also whether the age of initiation of alcohol use accounts for known gender differences in the severity of alcohol misuse.

METHOD

Data were taken from an ethnically diverse sample of 808 (412 male) students who were recruited in grade 5 at age 10-11 and followed prospectively on an annual basis for the next 7 years to age 17-18. State-of-the-art missing data methodology was used to address nonresponse due to noninitiation of alcohol use. Structural equation modeling was used to examine hypotheses for the prediction of alcohol misuse.

RESULTS

A younger age of alcohol initiation was strongly related to a higher level of alcohol misuse at age 17-18 and fully mediated the effects of parent drinking, proactive parenting, school bonding, peer alcohol initiation and ethnicity, all measured at age 10-11, and perceived harmfulness of alcohol use, measured at age 10-11 and age 11-12. However, age of alcohol initiation did not fully account for gender differences in the level of alcohol misuse at age 17-18. To further examine the role of gender, interactions between gender and school bonding, and gender and friend's alcohol initiation, were evaluated. However, neither of the interaction terms had direct effects on either age of initiation or level of alcohol-related problems.

CONCLUSIONS

Most measured risk factors for alcohol misuse were mediated through age of alcohol initiation. Only gender differences in alcohol misuse at age 17-18 were not mediated by age of alcohol initiation. Variables associated with these differences require further study. The results of this study indicate the importance of prevention strategies to delay the age of initiation of alcohol use.

Role of the self-image and smoker stereotype in smoking onset during early adolescence: a longitudinal study

The present study utilized a longitudinal design to assess whether self-consistency or self-enhancement motives are predictive of future smoking onset. Participants were 1,222 nonsmoking 5th through 8th graders who were followed into the next academic year. The results showed that teens who were above the median in similarity between their self-image and smoker stereotype on coolness, sociability, and intelligence were almost twice as likely to show smoking onset at the 2nd measurement. This is supportive of a self-consistency motive for adolescent smoking. The results of this study provide an important extension to previous cross-sectional research in this area.

Role of the self-image and smoker stereotype in smoking onset during early adolescence: a longitudinal study

The present study utilized a longitudinal design to assess whether self-consistency or self-enhancement motives are predictive of future smoking onset. Participants were 1,222 nonsmoking 5th through 8th graders who were followed into the next academic year. The results showed that teens who were above the median in similarity between their self-image and smoker stereotype on coolness, sociability, and intelligence were almost twice as likely to show smoking onset at the 2nd measurement. This is supportive of a self-consistency motive for adolescent smoking. The results of this study provide an important extension to previous cross-sectional research in this area.

Maximizing the Usefulness of Data Obtained with Planned Missing Value Patterns: An Application of Maximum Likelihood Procedures

Researchers often face a dilemma: Should they collect little data and emphasize quality, or much data at the expense of quality? The utility of the 3-form design coupled with maximum likelihood methods for estimation of missing values was evaluated. In 3-form design surveys, four sets of items. X, A, B, and C are administered: Each third of the subjects receives X and one combination of two other item sets - AB, BC, or AC. Variances and covariances were estimated with pairwise deletion, mean replacement, single imputation, multiple imputation, raw data maximum likelihood, multiple-group covariance structure modeling, and Expectation-Maximization (EM) algorithm estimation. The simulation demonstrated that maximum likelihood estimation and multiple imputation methods produce the most efficient and least biased estimates of variances and covariances for normally distributed and slightly skewed data when data are missing completely at random (MCAR). Pairwise deletion provided equally unbiased estimates but was less efficient than ML procedures. Further simulation results demonstrated that nun-maximum likelihood methods break down when data are not missing completely at random. Application of these methods with empirical drug use data resulted in similar covariance matrices for pairwise and EM estimation, however, ML estimation produced better and more efficient regression estimates. Maximum likelihood estimation or multiple imputation procedures. which are now becoming more readily available, are always recommended. In order to maximize the efficiency of the ML parameter estimates, it is recommended that scale items be split across forms rather than being left intact within forms.

Resistance-skills training and onset of alcohol use: evidence for beneficial and potentially harmful effects in public schools and in private Catholic schools

Recent research suggests that the success of social influence prevention programs is due to enhancing an adolescent's ability to resist passive social pressure (e.g., social modeling and overestimation of peer use), and is not due to teaching refusal skills for combating active social pressure (i.e., alcohol and drug offers). Using 4 waves of longitudinal data (collected in the 5th, 6th, 7th, and 8th grades) from 11,995 students participating in the Adolescent Alcohol Prevention Trial, resistance-skills training was found to be an effective strategy for preventing the onset of alcohol use when program assumptions were met. However, a counterproductive effect was found for adolescents attending public school who received a resistance training only condition.

Resistance-skills training and onset of alcohol use: evidence for beneficial and potentially harmful effects in public schools and in private Catholic schools

Recent research suggests that the success of social influence prevention programs is due to enhancing an adolescent's ability to resist passive social pressure (e.g., social modeling and overestimation of peer use), and is not due to teaching refusal skills for combating active social pressure (i.e., alcohol and drug offers). Using 4 waves of longitudinal data (collected in the 5th, 6th, 7th, and 8th grades) from 11,995 students participating in the Adolescent Alcohol Prevention Trial, resistance-skills training was found to be an effective strategy for preventing the onset of alcohol use when program assumptions were met. However, a counterproductive effect was found for adolescents attending public school who received a resistance training only condition.

Changes in the relationship between child support payments and educational attainment of offspring, 1979-1988

We examine changes over the 1980s in the effect of child support payments on the educational attainment of children age 16 to 19 in the United States, and why child support has a stronger impact than other sources of income. We use 1979 and 1988 Current Population Survey data, covering a period when improvements in enforcement should have increased the proportion of reluctant fathers paying support. We hypothesize and find that the positive effect of child support on education diminished somewhat over this period, both absolutely and in relation to other income.

A latent structure analysis of the positive and negative symptoms in schizophrenia

Although previous studies have suggested the inadequacy of the two-factor models of positive and negative symptoms in schizophrenia, confirmatory testing of the putative three-factor models is needed. Using a sample of 193 individuals diagnosed with schizophrenia, this study tested the relative goodness-of-fit of one-, two-, and three-factor models of the positive and negative symptoms. Using confirmatory factor analysis (CFA), the three-factor model of Addington et al., Arndt et al., and Liddle and Barnes that specifies positive, negative, and disorganized factors had the best fit with the data. Allowing the factors to co-vary and specifying dimensionality to the negative symptoms substantially improved the fit of the model. The study addressed several other issues. First, whereas the correlation between positive and negative symptoms was modest, the disorganized symptoms were significantly and more strongly related to both the positive and negative symptoms. Second, depression was not correlated with negative symptoms, but was significantly related to both the positive and disorganized symptoms. Third, the relationships between the three factors and levels of global, social, and work functioning in the sample supported the criterion-related validity of the three-factor model.

Peer influence on smoking initiation during early adolescence: a comparison of group members and group outsiders

In this study, the authors compared group members' and group outsiders' susceptibility to the influence of their friends' smoking. Ss were nonsmokers in Grade 7 who were observed for 1 year. Consistent with their hypothesis, the authors found that group outsiders (Ss who did not have reciprocal friends) were affected more by the smoking of their best friend and by the overall level of smoking among their friends than group members were. Furthermore, this peer influence was strongest for teens who were very concerned about their friends' reactions to their substance use. In addition, consistency in smoking status was related to the formation, but not the breakdown, of reciprocal friendships. Results indicated that teenagers may view smoking as a vehicle for entering a desired friendship group. The authors suggest ways that prevention programs might address this mechanism for adolescent smoking initiation.

Crossvalidation of Latent Class Models of Early Substance Use Onset

Cudeck and Browne (1983) were among the first to discuss the advantages of taking a crossvalidation approach to testing of covariance structure models. The purpose of this paper is to expand on Cudeck and Browne's work in two directions. The first direction of expansion is into testing of latent class models. The second direction of expansion involves using crossvalidation to examine differences between groups, where groups may be formed by gender, ethnicity, region, etc. In the present article crossvalidation is used to help select models of early substance use onset in a sample of young adolescents. The results suggest that the nature of the substance use onset process and the rate of movement through the process are the same for males and females at seventh and eighth grade. However, the present study did find evidence for gender differences in substance use experience at the beginning of seventh grade, with males somewhat more advanced in the onset process. The results also suggest that double crossvalidation is greatly to be preferred over single crossvalidation.

Testing the generalizability of intervening mechanism theories: understanding the effects of adolescent drug use prevention interventions

Outcome research has shown that drug prevention programs based on theories of social influence often prevent the onset of adolescent drug use. However, little is known empirically about the processes through which they have their effects. The purpose of the present study was to evaluate intervening mechanism theories of two program models for preventing the onset of adolescent drug use. Analyses based on a total of 3077 fifth graders participating in the Adolescent Alcohol Prevention Trial revealed that both normative education and resistance training activated the causal processes they targeted. While beliefs about prevalence and acceptability significantly mediated the effects of normative education on subsequent adolescent drug use, resistance skills did not significantly predict subsequent drug use. More impressively, this pattern of results was virtually the same across sex, ethnicity, context (public versus private school students), drugs (alcohol, cigarettes, and marijuana) and levels of risk and was durable across time. These findings strongly suggest that successful social influence-based prevention programs may be driven primarily by their ability to foster social norms that reduce an adolescent's social motivation to begin using alcohol, cigarettes, and marijuana.

Latent transition analysis and how it can address prevention research questions

The objective of this chapter is to introduce latent transition analysis (LTA) to the substance use prevention research community. LTA is a new methodological technique for testing stage-sequential models, such as models of substance use onset. LTA estimates several different sets of parameters. One of these sets is the transition probability matrix, which contains information about the probability of movement between stages in the model. LTA can be used to evaluate the effectiveness of prevention intervention programs by comparing the transition probability matrices of the program and control groups. If the prevention program is successful, the transition probability matrices will indicate that the probability of moving to a more advanced stage of drug use is lower for the program participants than for the control group. An advantage of taking a stage-sequential approach is that examining the transition probability matrix reveals how effective a program is for individuals entering the program with different levels and types of substance use experience. In this chapter, LTA is used to evaluate a variety of models of the early onset process separately for Anglo, Latino, and Asian-American adolescents, measured in seventh grade and again in eighth grade. Although somewhat different models are found to fit the three ethnic groups best, the differences likely are due to differences in the overall amount of substance use experience. Based on these results, it is suggested that, to be most effective, prevention programs should take place earlier for Anglos and Latinos, and later, followed by boosters, for Asian Americans.

Analysis with missing data in drug prevention research

Missing data problems have been a thorn in the side of prevention researchers for years. Although some solutions for these problems have been available in the statistical literature, these solutions have not found their way into mainstream prevention research. This chapter is meant to serve as an introduction to the systematic application of the missing data analysis solutions presented recently by Little and Rubin (1987) and others. The chapter does not describe a complete strategy, but it is relevant for (1) missing data analysis with continuous (but not categorical) data, (2) data that are reasonably normally distributed, and (3) solutions for missing data problems for analyses related to the general linear model in particular, analyses that use (or can use) a covariance matrix as input. The examples in the chapter come from drug prevention research. The chapter discusses (1) the problem of wanting to ask respondents more questions than most individuals can answer; (2) the problem of attrition and some solutions; and (3) the problem of special measurement procedures that are too expensive or time consuming to obtain for all subjects. The authors end with several conclusions: Whenever possible, researchers should use the Expectation-Maximization (EM) algorithm (or other maximum likelihood procedure, including the multiple-group structural equation-modeling procedure or, where appropriate, multiple imputation, for analyses involving missing data [the chapter provides concrete examples]); If researchers must use other analyses, they should keep in mind that these others produce biased results and should not be relied upon for final analyses; When data are missing, the appropriate missing data analysis procedures do not generate something out of nothing but do make the most out of the data available; When data are missing, researchers should work hard (especially when planning a study) to find the cause of missingness and include the cause in the analysis models; and Researchers should sample the cases originally missing (whenever possible) and adjust EM algorithm parameter estimates accordingly.

Diffusion of a school-based substance abuse prevention program: predictors of program implementation

BACKGROUND

The present study addresses diffusion of a psychosocial-based substance abuse prevention program, including: (a) teacher adoption, implementation, and maintenance; (b) teacher characteristics associated with implementation; (c) the relationship between integrity of program delivery and program outcomes; and (d) the effectiveness of teacher training and school principal involvement in increasing implementation.

METHODS

Participants were teachers (n = 60), school principals (n = 25), and fifth-grade students (n = 1147) from four Los Angeles area school districts. Districts were randomly assigned to an intensive or brief teacher training condition. Schools were randomly assigned to a principal-intervention or a no-principal-intervention condition. Assessments included teacher and principal self-reports, classroom observations of program delivery, and evaluation of immediate program outcomes.

RESULTS

During the first year, 78% of trained teachers implemented one or more program lessons. During the second year, only 25% maintained implementation of the program. Implementors reported fewer years of teaching experience and stronger self-efficacy, enthusiasm, preparedness, teaching methods compatibility, and principal encouragement than did nonimplementors. The principal intervention increased rates of implementation, but the intensive teacher training did not. Integrity of program delivery was positively associated with immediate program outcomes.

CONCLUSIONS

Program implementation was highly variable, suggesting that widespread teacher use of psychosocial-based programs cannot be taken for granted. Strategies for increasing implementation and maintenance need to be developed.

Evaluating interventions with differential attrition: the importance of nonresponse mechanisms and use of follow-up data

Evaluations of psychological interventions are often criticized because of differential attrition, which is cited as a severe threat to validity. The present study shows that differential attrition is not a problem unless the mechanism causing the attrition is inaccessible (unavailable for analysis). With a simulation study, we show that conclusions about program effects (a) are unbiased when there is no differential attrition, even with usual complete cases analysis; (b) may be severely biased when based on usual complete cases analyses and there is differential attrition; (c) are unbiased when based on the expectation-maximization (EM) algorithm, even when there is differential attrition, as long as the attrition mechanism is accessible; and (d) are biased, even with the EM algorithm, when the attrition mechanism is inaccessible. Following Little and Rubin (1987), we advocate the collection of new data from a random sample of subjects with initially missing data. On the basis of these data, we propose a simple correction to the EM algorithm estimates. In our study, the correction produced unbiased estimates of program effects parameters, even with an inaccessible attrition mechanism and substantial differential attrition.

Program integrity as a moderator of prevention program effectiveness: results for fifth-grade students in the adolescent alcohol prevention trial

This study reports the results of a test of the quality of program delivery (program integrity) as a variable that may moderate the effectiveness of alcohol prevention programs. Two theory-based programs, Resistance Training and Normative Education, were delivered to fifth-grade students who were then tested on program relevant mediating variables. Resistance Training was found to improve students' knowledge of peer pressure resistance strategies, their performance on a behavioral assessment of peer pressure resistance skills and the manifestation of their future intentions to drink alcohol. Normative Education was found to improve students' perceptions of a conservative norm regarding alcohol use, facilitated their belief that refusing unwanted offers to drink alcohol could be easily accomplished and reduced their perceptions of the prevalence of alcohol use. Program integrity was measured by program specialists who taught the programs to students and by trained observers. Ratings of program integrity were found to significantly moderate outcomes for three of seven mediating variables. Affected were knowledge of peer pressure resistance strategies, behavioral pressure resistance skills and perceived self-efficacy. These results suggest that the quality of program delivery and reception may play an important moderating function on prevention program effectiveness.

Controlling Correlational Bias via Confirmatory Factor Analysis of MTMM Data

Confirmatory factor analysis of multitrait-multimethod (MTMM) data has proven to be a useful tool for assessing convergent and discriminant validity. However, researchers have not made full use of the results of MTMM analyses in examining the relationship between MTMM factors and variables outside the MTMM. Often, researchers simply average the various measures of each trait. Alternatively, they estimate LISREL MTMM models, but estimate only relationships between MTMM traits and the outside variables. In the present article, we show that these two approaches to analyzing data outside the MTMM produce equally highly biased parameter estimates when the actual correlations between MTMM method factors and the outside variables are substantial. An algebraic explanation and a simulated data illustration are given for the bias due to misspecification. Also, the problem is illustrated with a brief empirical example. Implications for applied research are discussed.

Preventing alcohol, marijuana, and cigarette use among adolescents: peer pressure resistance training versus establishing conservative norms

BACKGROUND

Two strategies for preventing the onset of alcohol abuse, and marijuana and cigarette use were tested in junior high schools in Los Angeles and Orange Counties, California. The first strategy taught skills to refuse substance use offers. The second strategy corrected erroneous normative perceptions about prevalence and acceptability of use among peers and established conservative groups norms regarding use.

METHODS

Four experimental conditions were created by randomly assigning schools to receive (a) neither of the experimental curricula (placebo comparison), (b) resistance skill training alone, (c) normative education alone, or (d) both resistance skill training and normative education. Students were pretested prior to the program and post-tested 1 year following delivery of the program.

RESULTS

There were main effects of normative education for summary measures of alcohol (P = 0.0011), marijuana (P = 0.0096), and cigarette smoking (P = 0.0311). All individual dichotomous measures of alcohol, marijuana, and tobacco use indicated significant reductions in onset attributable to normative education. There were no significant main effects of resistance skill training.

CONCLUSION

These results suggest that establishing conservative norms is an effective strategy for preventing substance use.

Social influence processes affecting adolescent substance use

Social influence is central to models of adolescent substance use. Nonetheless, researchers fail to delineate the various forms of social influence. A framework that distinguishes between active (explicit drug offers) and passive (social modeling and overestimation of friends' use) social pressure was tested. The effect of these processes on alcohol and cigarette use was examined with 526 seventh graders taking part in an alcohol prevention program. Hierarchical regression analyses demonstrated that pretest measures of alcohol use, offers, modeling, and overestimation each accounted for unique variance in posttest alcohol use. Similar results were obtained for cigarette smoking. The general model was not significantly different for boys and girls, or for prior users and prior nonusers, supporting the generalizability of the framework. Implications for intervention programs are discussed.

Modeling transitions in latent stage-sequential processes: a substance use prevention example

This article illustrates the use of latent transition analysis (LTA), a methodology for testing stage-sequential models of individual growth. LTA is an outgrowth of latent class theory and is a particular type of latent Markov model emphasizing the use of multiple manifest indicators. LTA is used to compare the fit of two models of early adolescent substance use onset and to assess the effects of a school-based substance use prevention program on Ss measured in 7th grade and again in 8th grade. Several interesting findings emerged. First, a model of substance use onset including both alcohol and tobacco use as possible starting points fit better than a model that included alcohol use as the only starting point. Second, Ss who had tried tobacco but not alcohol in in 7th grade seemed to be on an accelerated onset trajectory. Third, the normative education prevention program was generally successful, except for the students who had tried only tobacco in 7th grade.

Drug use prevention programs, gender, and ethnicity: evaluation of three seventh-grade Project SMART cohorts

One-year follow-up data from three seventh-grade cohorts of Project SMART were examined to assess the effects of two social psychology-based programs within each of six subgroups: males, females, Asians, blacks, Hispanics, and whites. The three cohorts (total N = 5,070) were those receiving curriculum or serving as controls as seventh-graders in 1982-1983, 1983-1984, and 1984-1985 school years. The outcome measures used were composite indices based on lifetime and recent use items for cigarettes, alcohol, and marijuana. The major analysis was ANCOVA on classroom means for the composite indices at post-test, using pretest classroom means for the indices as a covariate. The results showed clear prevention effects for females but not for males. Overall prevention effects were strongest for cigarette smoking, but were also evident for alcohol. Significant sex by program interactions, showing differential program effects for males and females, were found for cigarettes and marijuana, but not for alcohol. There was a nonsignificant trend suggesting that the programs were most effective for Asians and least effective for whites.

Evidence for two paths of alcohol use onset in adolescents

Research is needed to identify risk factors specifically associated with the development of substance abuse. The current study explored the possibility that adolescents classified as having a problem behavior prone orientation (Type II) are predisposed to more rapid alcohol use onset compared to more normally socialized (Type I) adolescents. It was hypothesized that both types of adolescents would increase their alcohol use over time, but that problem behavior prone adolescents would increase their rates of alcohol consumption more rapidly than would normally socialized adolescents. Using ANCOVA (with baseline alcohol use as a covariate) and t tests (examining only nondrinkers at baseline), the hypotheses were strongly supported. Both Type I and Type II adolescents significantly increased their alcohol use over a one-year period. Type II adolescents, in comparison to Type I adolescents, had significantly higher alcohol use. The greater alcohol use among Type II adolescents was attributed to their problem behavior prone orientation. The findings suggest the existence of two different developmental pathways of alcohol use onset, one initiated by normally socialized adolescents and the other by adolescents with a problem behavior prone orientation. Future alcohol abuse prevention programs may benefit from tailored intervention strategies which take into account population specific risk factors.

Activity involvement, risk-taking, demographic variables, and other drug use: prediction of trying smokeless tobacco

Four activity participation variables (clubs, sports, church, and parties); two indices of "risk-taking" (preference for risk-taking, getting into trouble at school); three demographic variables (sex, ethnic group, socioeconomic status); and two drug use variables (trial of cigarettes and alcohol) were examined as correlates and prospective predictors of trial of smokeless tobacco in two cohorts of seventh graders in urban Los Angeles. The data were analyzed separately for males and females. Cross-sectional logistic regression analyses indicated that correlates of trying smokeless tobacco among the seventh-grade cohorts or among these same cohorts in the eighth grade (considering those persons who had not tried smokeless tobacco in seventh grade) generally included being white, trying cigarettes, risk-taking, and attending parties. Prospective logistic regression analyses with data from subjects who had not tried smokeless tobacco in the seventh grade indicated that predictors of subsequent trial of it generally included only being white and having tried cigarettes. Sports participation predicted onset only in one cohort of female subjects but not in males. Some activities that have been proposed as being predictive of smokeless tobacco use (e.g., sports participation) are generally irrelevant for a large sample of young adolescents in urban Los Angeles. White male cigarette smokers, regardless of the activities they have engaged in, are most likely to try smokeless tobacco.

The impact of the differences in the decline of dental school applicants in the United States and Canada

The number of individuals writing the Canadian Dental Association Dental Aptitude Test and the American Dental Association Dental Admissions Test for the first time is used as a measure of the number of new additions to the dental school applicant pool in each of the past 15 years. Dramatic changes have occurred during that period. Comparisons are made and similarities noted between the situations in the United States and Canada. A discussion of the probable causes of the differences highlights the changing government programs in the two countries, the perceptions of potential applicants, and the attitudes of members of the dental profession. Some suggestions for future action are proposed.

Affective and social influences approaches to the prevention of multiple substance abuse among seventh grade students: results from project SMART

Two drug abuse prevention curricula were tested to determine their efficacy in preventing the onset of tobacco, alcohol, and marijuana use among adolescents. The first program focused on prevention through social pressure resistance training. The second featured affective education approaches to prevention. Curricula were tested on seventh grade students. Subjects were pretested just prior to the program and were post-tested at 12 and 24 months. Post-test analyses indicated that the social program delivered to seventh grade subjects was effective in delaying the onset of tobacco, alcohol, and marijuana use. No preventive effect of the affective education program was observed. By the final post-test, classrooms that had received the affective program had significantly more drug use than controls.

The consistency of peer and parent influences on tobacco, alcohol, and marijuana use among young adolescents

The purpose of this study was to determine the degree to which the use of tobacco, alcohol, and marijuana by young adolescents can be described using a common theoretical model. Structural models were created in which psychosocial variables hierarchically predicted the use of each substance. The fit of a model in which paths from predictor variables were constrained to be equal was not inferior in any meaningful way to that of a model in which all path coefficients were freely estimated, thus suggesting that use of tobacco, alcohol, and marijuana by young adolescents may be considered to be a unitary phenomenon. A simplified model, in which these substances were combined into a single latent variable, showed a good fit. The results of these analyses suggest that it may be beneficial to consider adolescent substance use to be a unitary phenomenon.

Path model of multidimensional compliance with cancer therapy

Patients newly diagnosed with hematologic malignancies were followed for a 6-month treatment period to assess compliance with three regimen requirements for cancer therapy: anti-neoplastic medication self-administered intermittently, supportive medication self-administered daily, and monthly clinic appointments. The effect on compliance of three intervention "packages" (some combination of education, shaping of pill-taking behavior, and home restructuring) and the extent that patient satisfaction, knowledge, and uncertainty about illness-related events mediated the effects of the interventions were also examined. Blood levels of the drugs and self-report measures indicated that compliance with daily pill taking was higher for each intervention group compared to a control group. Similar results were obtained for compliance with clinic appointments. No improvement in intermittent self-medication was found. Although each intervention package increased patient knowledge and satisfaction, path analyses demonstrated that knowledge did not affect any aspect of compliance, whereas satisfaction was associated with increased appointment keeping only. Daily pill taking was influenced directly by the behavioral components of the interventions. Uncertainty did not influence compliance but was associated with depression, which was negatively correlated with intermittent self-medication.

High-school smoking prevention: results of a three-year longitudinal study

This study compared two strategies for preventing cigarette smoking among high-school students. One strategy emphasized social-pressure resistance skills, while the other focused on education about health concerns which are relevant to high-school students. Additionally, the use of same-age peer leaders and the use of familiar models in media presentations were investigated. The results suggest that social-influences resistance training was efficacious in reducing transitions to higher use by those who had previously experimented with cigarettes. Health education was most effective in preventing initial experimentation among those who had not smoked prior to the beginning of the study. Neither program was effective in limiting transitions among those who had gone beyond the experimental stage of smoking, and neither had any effect on encouraging cessation. There were no differences which could be attributed to peer leaders or to familiar media models. During later adolescence, a combined health education and social skills training approach is advocated. It is suggested that while there are some gains by implementing programs during late adolescence, prevention programs targeted at younger students may be more effective generally.

Role of health locus of control beliefs and expectations of treatment efficacy in adjustment to cancer

We examined the effects of health locus of control beliefs (self-, doctor, and chance control) and expectations of treatment efficacy on short-term psychological adjustment in a sample of newly diagnosed cancer patients. The role of these beliefs and expectations in moderating the relation between (perceived and actual) disease severity and depression was also examined. The data were collected within one week of diagnosis. The relation between perceptions of disease severity and depression was weaker for those who believed that they could personally control their health and for those who held positive expectations about the effects of complying with medical treatment. Similar patterns were found when disease severity was defined in terms of prognosis for survival. Strong negative correlations between self-control/treatment expectations and depression were found for those who perceived that their illness was very severe. The results for chance and doctor control were less consistent. The stability of health control beliefs and treatment expectations over the course of a serious long-term illness is discussed.

Role of health locus of control beliefs and expectations of treatment efficacy in adjustment to cancer

We examined the effects of health locus of control beliefs (self-, doctor, and chance control) and expectations of treatment efficacy on short-term psychological adjustment in a sample of newly diagnosed cancer patients. The role of these beliefs and expectations in moderating the relation between (perceived and actual) disease severity and depression was also examined. The data were collected within one week of diagnosis. The relation between perceptions of disease severity and depression was weaker for those who believed that they could personally control their health and for those who held positive expectations about the effects of complying with medical treatment. Similar patterns were found when disease severity was defined in terms of prognosis for survival. Strong negative correlations between self-control/treatment expectations and depression were found for those who perceived that their illness was very severe. The results for chance and doctor control were less consistent. The stability of health control beliefs and treatment expectations over the course of a serious long-term illness is discussed.

Child support awards: differentials and trends by race and marital status

This study has analyzed data from combined 1979 and 1982 April supplements to the Current Population Survey to study differences in the award of child support by race and marital status. The following findings emerge from this study: The percentage of women with children present from an absent father who are awarded child support varies greatly by race and marital status. Among all women, nonblacks are more than twice as likely as blacks to have a child support award, and the ever-married are almost six times as likely as the never-married to have an award. Among the ever-married, currently separated women are approximately half as likely as the ever-divorced to have secured an award. The lower probability of child support awards among blacks can be attributed in part to their disproportionate membership in marital status groups with lower award probabilities. Blacks are four and one-half times as likely as nonblacks to be among the never-married and almost twice as likely to be among the currently separated. Racial differences in award probabilities exist within all marital status groups except the never-married. Among the currently separated, blacks are one-third less likely than nonblacks to have an award. Among the ever-divorced, blacks are almost one-fourth less likely than nonblacks to have an award. Among the never-married, unlike the ever-married, virtually no statistically significant socioeconomic characteristics appear to distinguish mothers who have a child support award from those who do not. Among all women, 50 to 60 percent of the gross racial differential in award rates can be explained by observed differences in such economic and demographic characteristics as marital status, educational attainment, age, place of residence, and number of children. Among the ever-married, 50 percent of the gross racial difference can be explained by these factors. Among the ever-married, the likelihood of being awarded child support at marital disruption has increased over time, but this upward trend has been different for blacks and nonblacks. Among nonblacks, the proportion of women obtaining a child support award increased 1.3 percent per year between 1960 and 1975 and then declined 0.4 percent per year since then. Among blacks, the proportion increased 0.8 percent per year between 1960 and 1975 and then accelerated to 1.6 percent per year since then.(ABSTRACT TRUNCATED AT 400 WORDS)

Self-initiated smoking cessation among high school students

The purpose of this study was to examine psychosocial predictors of self-initiated smoking cessation among high school students. Students from nine high schools were pretested using a questionnaire which assessed smoking behavior, beliefs about positive and negative consequences of smoking, moral attitudes toward smoking, normative expectations about smoking, rebelliousness, peer smoking and parent smoking. Smokers identified at pretest were reexamined three months and fifteen months later. Three variables, moral attitudes, peer smoking and positive beliefs about smoking significantly discriminated continuing smokers from quitters at the three-month posttest. Three different variables, negative beliefs about smoking, parental smoking and rebelliousness significantly discriminated between those who quit and later relapsed and those who quit and maintained their non-smoking status at the 15 month posttest. Smoking characteristics at pretest failed to discriminate either those who would quit or those who would maintain their non-smoking status. Results support the development of public information programs which encourage early cessation of smoking which feature the development of appropriate attitudes and beliefs and which foster social support.

Constructing the cost of health professions education

Pressures at the national, state, and institutional levels are forcing health professions education administrators to justify their budget requests. Because unit cost studies traditionally used by higher education have proved unsatisfactory, program constructed cost models have been developed. The advantages of the model for administrators lie in the fact that any input unit of the model can be adjusted and the effects of that adjustment can be measured against the cost per student. In times of budget restrictions, these adjustments permit administrators to model various combinations of student enrollment, faculty involvement, class size, and basic program structure to obtain the optimal education experience from available resources. The model is applied by way of example to all nonbaccalaureate dental hygiene education programs in the United States.

Reliability of self-report measures of drug use in prevention research: evaluation of the Project SMART questionnaire via the test-retest reliability matrix

The present article describes an evaluation of a self-report questionnaire administered to whole classrooms of 7th graders. Using the test-retest reliability matrix (based on concepts of Cronbach [1] and Campbell and Fiske [2]), eight of nine drug-use indices appeared to have acceptable to good reliability. The three measures included in the test-retest reliability matrix provide stronger evidence for good reliability than could any single measure.

Radiology instruction and use of ionizing radiation in U.S. dental schools

In fall 1980, the Commission on Dental Accreditation of the American Dental Association conducted a comprehensive survey of radiology instruction and the use of ionizing radiation in dental education. All 60 dental schools in the United States responded to the survey. Data were collected on course objectives, course content, clock hours of instruction, radiology content in other clinical courses, the number, educational background, and years of teaching experience of radiology faculty, clinical requirements in radiology and the measures used to assess student competency, and the use of radiographs in providing patient care. Attention was directed to practices used in monitoring radiation protection and hygiene. These data provide a frame of reference for evaluating the status of radiology instruction at the respective schools. More important, they provide faculty with a baseline for determining what changes, if any, are needed in the current radiology curriculum.

Infrapopliteal bypass grafting: use of upper limb vein alone and in autogenous composite grafts

Thirty-seven consecutive vein grafts to the infrapopliteal arteries are reviewed. Upper limb vein was used in each case, either for the entire graft (27%) or in combination with saphenous vein (73%). The grafts were inserted during a 10-year period and constituted 8.6% of the lower limb grafts carried out during this time. There was one postoperative death (2.7%). The patency rate at 3 years was 58 +/- 9.5% and at 5 years 49.1 +/- 11.5%. Indications for the use of upper limb vein in these situations are considered, and the results are compared with those obtainable with other materials. Upper limb vein can provide a satisfactory arterial substitute in the lower limb, and it may occasionally be the material of choice.