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Explaining adolescent drug use: an elaboration strategy for structural equations modeling.

We report a series of analyses designed to estimate increasingly elaborated theoretical models that explain adolescent drug use. Each of the successive elaborations adds a theoretical construct to the explanatory model in order to increase our understanding of drug use by specifying in greater detail the nature of the structural relationships among the latent variables. The more detailed specification is accomplished by 1) specifying new direct effects that increase explained variance in drug use, 2) decomposing direct effects through the interpolation of hypothesized intervening variables, 3) specifying antecedents of variables that modify their direct effects, and 4) exposing suppressor effects. Where indicated, we evaluate alternative explanations of the observed relationships. We do this by controlling for common antecedent effects to reduce spuriousness or by examining different specifications of causal linkages among the explanatory constructs.

Adolescent

Reserve capacity of the elderly in aging sensitive tests of fluid intelligence: a reanalysis via a structural equation modelling approach.

In the last decade there has been a growing interest among developmental psychologists to investigate whether the cognitive performance of older adults can be improved by means of training programs. A number of cognitive training studies involving aging sensitive abilities of fluid intelligence have been performed with healthy older adults (Willis et al. 1981; Baltes et al., 1984/1986). In this paper we reanalyse data from Baltes et al. (1986) concerning the ADEPT Induction, ADEPT Figural Relations, Induction Standard and the Raven's Advanced Progressive Matrices Tests. In contrast to the above study, where the data analysis was based on a MANOVA approach, usually carried out when experimental data were gathered, this discussion implements an approach to change measurement for which the structural equation of different aspects of change in means as manifested in the moment matrices. The results here confirm these by Baltes et al. (1986), and suggest conclusions concerning change in means over time in the experimental and control groups, which are not implied by their study.

Aged

Testing structural equation models for twin data using LISREL.

Simple genetic models can be fitted to twin data using software packages such as LISREL (Jöreskog and Sörbom, 1986a). After discussion of data preparation and routine checks on possible violation of assumptions of the twin method, we illustrate univariate, bivariate, and multivariate genetic models which can be tested in cross-sectional twin data using LISREL. These include models for cohort or cohabitation effects, genotype x sex interaction, and certain types of genotype x environment interaction and genotype-environment correlation.

Computer Simulation

The impact of late adolescent substance use on young adult health status and utilization of health services: a structural-equation model over four years.

This study examined the impact of adolescent substance use on young adult health status and health service utilization, while controlling for earlier subjective and objective health problems and seeking medical care. Data were obtained from 654 participants when they were in late adolescence and 4 years later when they were young adults. Latent-variable models were used to determine what effect, if any, adolescent drug use had on later health. A second-order factor of general drug use had a small, but significant, influence on decreasing subjective physical hardiness over the 4-year period. However, general drug use was not directly related to later physical symptomatology, subjective health problems, or health service utilization. General cigarette use and amount of cigarette smoking were significantly related to a range of health outcomes including increased psychosomatic symptoms, respiratory symptoms, reporting trouble with health, nights spent in the hospital, and health service utilization, as well as decreased subjective physical hardiness. Early cannabis use decreased later subjective physical hardiness and increased health problems experienced over the 4 years. Hard drug use was associated with increased emergency physician visits during adolescence and increased perceived trouble with health as young adults. Due to the fact that adolescent general drug use decreased subjective physical hardiness over 4 years, it is possible that continued substance use might lead to more serious objective health consequences later in life (i.e. physical symptoms).

Adolescent

Therapeutic empathy and recovery from depression in cognitive-behavioral therapy: a structural equation model.

This study demonstrated that therapeutic empathy has a moderate-to-large causal effect on recovery from depression in a group of 185 patients treated with cognitive-behavioral therapy (CBT). The authors simultaneously estimated the reciprocal effect of depression severity on therapeutic empathy and found that this effect was quite small. In addition, homework compliance had a separate effect on clinical recovery, over and above the effect of therapeutic empathy. The patients of novice therapists improved significantly less than did the patients of more experienced therapists, when controlling for therapeutic empathy and homework compliance. Ss who terminated therapy prematurely were less likely to complete the self-help assignments between sessions, rated their therapists as significantly less empathic, and improved significantly less. Ss with borderline personality disorder improved significantly less, but they rated their therapists as just as empathic and caring as other patients. The significance of these findings for psychotherapy research, treatment, and clinical training is discussed.

Adolescent

Structural equation modelling of some of the determinants of suicide risk.

Much of the psychological research with suicidal patients has examined, individually or in combination, correlates and predictors of the various measures in the suicide process. The present study investigated suicidal risk as an outcome measure. Several questionnaires were administered to a sample of 94 soldiers, 61 of whom had manifested some suicidal symptoms. Using LISREL analysis, the data showed that the best model had suicide risk as directly influenced by depression and indirectly by impulsivity.

Adult

A multimethod assessment of social intervention effects on narcotics use and property crime.

Log-linear modeling, structural equation modeling, repeated measures analysis of variance, and time series analysis are discussed for their utility in evaluating the temporal effects of social interventions. Methods are illustrated by applications examining the independent and joint temporal effects of methadone maintenance treatment and legal supervision on narcotics use and property crime among narcotics addicts. Convergent results from a multimethod assessment of the issue show that methadone maintenance has long-term and short-term suppressive effects on narcotics use and property crime. More complicated but complementary findings have been found in evaluating the effectiveness of legal supervision.

Analysis of Variance

Empirical test of the interaction model of client health behavior.

The general concepts, variables, and relationships described by the Interaction Model of Client Health Behavior (IMCHB) were used to guide a secondary data analysis of 203 women's decisions to request an amniocentesis. Step-wise multiple regression explained 58% of the variance in these decisions by jointly examining the factors which define the client as unique in her responses to an at-risk pregnancy, as well as factors describing the client-provider interaction. The women could be correctly classified as users or nonusers of prenatal diagnosis with 87% accuracy in a discriminant analysis based on the variables derived from the conceptual model. Finally, structural equation modeling was used to estimate the causal paths described by the general model. While the relationships proposed in the model need further empirical evaluation, this first application serves to demonstrate the testability of the IMCHB and its potential to direct nursing inquiries.

Adult

Changing AIDS-risk behavior.

This article contains a comprehensive, critical review of the acquired immunodeficiency syndrome (AIDS)-risk-reduction literature on interventions that have targeted risky sexual behavior and intravenous drug use practices. A conceptually based, highly generalizable model for promoting and evaluating AIDS-risk behavior change in any population of interest is then proposed. The model holds that AIDS-risk reduction is a function of people's information about AIDS transmission and prevention, their motivation to reduce AIDS risk, and their behavioral skills for performing the specific acts involved in risk reduction. Supportive tests of this model, using structural equation modeling techniques, are then reported for populations of university students and gay male affinity group members.

Acquired Immunodeficiency Syndrome

A structural model approach toward the development of a theory of the link between stress and mental health.

This study attempts to develop an empirical model of the link between stress and mental health, focusing particularly on occupational stress. Three different models were assessed-the person-stress model, the dispositional model, and the indigenous model--using structural equation modelling. The indigenous model was found to be the most predictive of mental health. In this model, personality and coping strategies precede and determine the perception of job stressors, which ultimately affect the mental well-being of the individual.

Adaptation, Psychological

Individual differences in cognitive arithmetic.

Unities in the processes involved in solving arithmetic problems of varying operations have been suggested by studies that have used both factor-analytic and information-processing methods. We designed the present study to investigate the convergence of mental processes assessed by paper-and-pencil measures defining the Numerical Facility factor and component processes for cognitive arithmetic identified by using chronometric techniques. A sample of 100 undergraduate students responded to 320 arithmetic problems in a true-false reaction-time (RT) verification paradigm and were administered a battery of ability measures spanning Numerical Facility, Perceptual Speed, and Spatial Relations factors. The 320 cognitive arithmetic problems comprised 80 problems of each of four types: simple addition, complex addition, simple multiplication, and complex multiplication. The information-processing results indicated that regression models that included a structural variable consistent with memory network retrieval of arithmetic facts were the best predictors of RT to each of the four types of arithmetic problems. The results also verified the effects of other elementary processes that are involved in the mental solving of arithmetic problems, including encoding of single digits and carrying to the next column for complex problems. The relation between process components and ability measures was examined by means of structural equation modeling. The final structural model revealed a strong direct relation between a factor subsuming efficiency of retrieval of arithmetic facts and of executing the carry operation and the traditional Numerical Facility factor. Furthermore, a moderate direct relation between a factor subsuming speed of encoding digits and decision and response times and the traditional Perceptual Speed factor was also found. No relation between structural variables representing cognitive arithmetic component processes and ability measures spanning the Spatial Relations factor was found. Results of the structural modeling support the conclusion that information retrieval from a network of arithmetic facts and execution of the carry operation are elementary component processes involved uniquely in the mental solving of arithmetic problems. Furthermore, individual differences in the speed of executing these two elementary component processes appear to underlie individual differences on ability measures that traditionally span the Numerical Facility factor.(ABSTRACT TRUNCATED AT 400 WORDS)

Cognition

Effect of a pharmacist-led mHealth app on adherence, quality of life, and glycaemic control in diabetes: A multicentre RCT.

AIMS: To evaluate whether CareAide&#xae;, a pharmacist-driven mHealth application, improves medication adherence, health-related quality of life (HRQoL), and glycaemic control in diabetes mellitus using structural equation modelling. METHODS: Pre-specified secondary analysis of the type 2 diabetes mellitus cohort from a 6-month multicentre open-label randomised controlled trial (N&#xa0;=&#xa0;663) across three Malaysian hospitals. Adherence was assessed by MMAS-8 (subjective) and Proportion of Days Covered (PDC; pharmacy-verified). HRQoL was measured by AQoL-6D and EQ-5D-5&#xa0;L. Structural equation modelling (SEM), Necessary Condition Analysis, and Importance-Performance Map Analysis (cIPMA) were applied. RESULTS: CareAide&#xae; produced large adherence gains (MMAS-8: 7.31 vs 5.55, d&#xa0;=&#xa0;1.64; PDC&#xa0;&#x2265;&#xa0;80%: 81.6% vs 33.0%; both p&#xa0;<&#xa0;0.001). Early 3-month adherence was the strongest predictor of sustained 6-month adherence in both models (&#x3b2; std&#xa0;=&#xa0;0.567 and 0.688; p&#xa0;<&#xa0;0.001). AQoL-6D utility improved significantly (0.669 vs 0.618; d&#xa0;=&#xa0;0.353, p&#xa0;<&#xa0;0.001), driven by coping (d&#xa0;=&#xa0;0.447) and relationships (d&#xa0;=&#xa0;0.254) domains. HRQoL did not mediate adherence; gains were a direct independent benefit. The intervention effect on HbA1c was not statistically significant in the PDC-based SEM model (&#x3b2;&#xa0;=&#xa0;&#xa0;-&#xa0;0.333, p&#xa0;=&#xa0;0.065); a group difference was, however, supported by baseline-adjusted ANCOVA (&#x3b2;&#xa0;=&#xa0;&#xa0;-&#xa0;0.41%, p&#xa0;=&#xa0;0.002), and the complete-case comparison was non-significant (p&#xa0;=&#xa0;0.153), so glycaemic findings warrant cautious interpretation. cIPMA identified the intervention as the primary optimisation target. CONCLUSIONS: CareAide&#xae; significantly improves medication adherence and psychosocial quality of life. Evidence for glycaemic benefit came from baseline-adjusted analysis (ANCOVA), though findings should be interpreted with caution given incomplete HbA1c data at one site. The first three months are the most critical period for pharmacist support. In this dataset, PDC appeared more sensitive than MMAS-8 to the HbA1c signal within 6&#xa0;months, but this finding requires confirmation in longer studies with more complete HbA1c data. TRIAL REGISTRATION: ClinicalTrials.gov NCT06068309.

Aged

Virtual reality physical education and adolescents' exercise interest and physical fitness: An explanatory sequential mixed-methods randomized trial with exploratory pathway analysis.

Traditional physical education (PE) faces declining student interest and limited fitness gains. Virtual reality (VR) offers immersive, gamified experiences, but evidence regarding its effectiveness and explanatory pathways remains limited. This explanatory sequential mixed-methods randomized trial assigned 360 adolescents (aged 13-16) from three middle schools to either VR-supported PE (n&#xa0;=&#xa0;180) or conventional PE (n&#xa0;=&#xa0;180) for 12&#xa0;weeks, with a 4-week follow-up. Outcomes included exercise interest (validated scale), physical fitness (coordination via MABC-2, cardiorespiratory endurance via the 20-m shuttle run, explosive power via the standing long jump, and speed via the 10-m sprint), and accelerometer-measured physical activity. The qualitative component involved 38 unique students: 32 completed individual semi-structured interviews, and six additional students participated only in focus groups. Three-level linear mixed-effects models and exploratory structural equation modeling were used. The VR group showed significantly greater improvements in exercise interest (d&#xa0;=&#xa0;0.78), coordination (d&#xa0;=&#xa0;0.62), cardiorespiratory endurance (d&#xa0;=&#xa0;0.55), and speed (d&#xa0;=&#xa0;0.48) than the control group (all p&#xa0;<&#xa0;0.001), but not in explosive power (d&#xa0;=&#xa0;0.12, p&#xa0;=&#xa0;0.148). Effects were partially retained at follow-up (interest d&#xa0;=&#xa0;0.65, coordination d&#xa0;=&#xa0;0.48, endurance d&#xa0;=&#xa0;0.42, and speed d&#xa0;=&#xa0;0.30), a pattern not fully consistent with a purely novelty-driven explanation. Exploratory mediation identified exercise interest as a statistically compatible explanatory pathway (indirect effect&#xa0;=&#xa0;0.34, 95% CI [0.22, 0.46]), although the timing of measurement precludes causal interpretation. Qualitative findings contextualized these results by highlighting immersion, feedback, self-efficacy, and perceived transfer. VR-supported PE may enhance adolescents' exercise interest and selected fitness dimensions, but its limited effect on explosive power and possible novelty contribution indicate that it should complement, rather than replace, conventional PE. Longer-term studies are needed.

Humans