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Biomedical subjects

M D Newcomb

Publications and source records attributed to M D Newcomb.

At least 55 records · Page 3Linked to original sources
PubMed1991

Personality, problem drinking, and drunk driving: mediating, moderating, and direct-effect models.

Three different general explanations of the effect of personality on problems from drinking alcohol were investigated. One general explanation involved mediating effects. The 2nd explanation involved direct effects of personality. The 3rd general personality process held that alcohol consumption and personality interact as moderating effects on drinking problems. Results provided support for each of the 3 general explanations of personality effects, although certain effects were found primarily for only 2 of the 6 personality constructs investigated (sensation seeking and cognitive motivation). These findings helped delimit the personality processes associated with drinking problems and demonstrated the viability of several specific processes that go beyond traditional assumptions about personality and problem drinking.

Adult↗
PubMed1991

Influence of sensation seeking on general deviance and specific problem behaviors from adolescence to young adulthood.

Indicators of a Sensation Seeking latent construct were assessed during adolescence and used to predict changes in repeatedly gathered measures of a latent construct of General Deviance. A community sample of 595 male and female Ss was assessed 3 times over a 5-year period from late adolescence to young adulthood. Most Ss reported use of licit drugs, about one half had tried illicit drugs, and a substantial minority had engaged in other delinquent or criminal activities. The General Deviance construct was stable over time, although specific cross-effects were found. Sensation Seeking was moderately correlated with General Deviance at all 3 levels but did not predict directly the General Deviance construct over time; the effects of Sensation Seeking on later deviant behavior and attitudes were specific rather than general.

Adolescent↗
PubMed1991

Effect of energy source fed to sows during late gestation on neonatal blood metabolite homeostasis, energy stores and composition.

Four experiments utilizing 49 primiparous and 34 multiparous sows were conducted to evaluate the effect of feeding either starch, soybean oil or medium-chain triglyceride (MCT) during late gestation (d 100 to parturition) on neonatal fasting blood glucose homeostasis (Exp. 1 and 2), d-100 maternal circulating insulin, glucagon and glucose concentrations (Exp. 3 and 4), neonatal energy stores (Exp. 3 and 4) and colostrum composition (Exp. 1, 2, 3 and 4). In all cases, sows were fed 7.2 Mcal/d of a diet that supplied 279 g of protein daily. During fasting, pigs from MCT-fed dams had higher blood glucose concentrations (P less than .05) than pigs from starch-fed dams. No differences between treatments were observed for total carcass fat, liver glycogen or carcass glycogen of pigs killed prior to suckling. In general, colostrum fatty acid profiles were influenced by diet; however, the shifts in fatty acids differed for experiments. Starch-fed sows had higher blood insulin and lower blood glucagon (P less than .05) than lipid-supplemented sows; however, sow blood glucose remained constant across treatments. This study indicates that any positive effects of feeding soybean oil to sows during late gestation are most likely mediated by a change in fatty acid composition of colostrum; any beneficial properties of MCT feeding most likely are mediated through improved blood glucose maintenance of the neonate when it is subjected to fasting conditions.

Animal Feed↗
PubMed1989

Substance use and abuse among children and teenagers.

During the past several years, there has been a renewed national concern about drug abuse, culminating in the current "war on drugs." In this review, we emphasize that even though child or teenage drug use is an individual behavior, it is embedded in a sociocultural context that strongly determines its character and manifestations. Our focus is on psychoactive substances both licit (cigarettes and alcohol) and illicit (e.g., cannabis and cocaine). We feel that it is critical to draw a distinction between use and abuse of drugs and to do so from a multidimensional perspective that includes aspects of the stimulus (drug), organism (individual), response, and consequences. Our selective review of substance use and abuse among children and adolescents covers epidemiology (patterns and extent of drug use), etiology (what generates substance use), prevention (how to limit drug use), treatment (interventions with drug users), and consequences (effects and outcomes of youthful drug use).

Adolescent↗
PubMed1989

Cigarette smokers do more than just smoke cigarettes.

In this study, we hypothesized that light and moderate-to-heavy cigarette smokers, when compared with nonsmokers, would exhibit significantly less healthy attitudes and behaviors on several dimensions relevant to the risk of coronary heart disease (CHD). A factor analysis of survey items measuring knowledge, attitudes, and behaviors in five CHD risk areas produced four major factors, which we labeled Attitudes (Factor 1), Health Consciousness (Factor 2), Knowledge (Factor 3), and Unhealthy Behaviors (Factor 4). Factor-based scales generated for each of these four factors were used in a one-way multivariate analysis of variance to examine differences between nonsmokers, light smokers, and moderate-to-heavy smokers. Cigarette smokers versus nonsmokers exhibited less positive attitudes toward CHD risk behaviors, whereas moderate-to-heavy cigarette smokers, as compared with the light smokers and the nonsmokers, exhibited lower levels of health consciousness and enacted unhealthy behaviors at a greater frequency. The moderate-to-heavy cigarette smokers also exhibited a lower commitment to enact healthy behavioral changes in the immediate future, even after corrections were introduced for their lower frequency of healthy behaviors during the past week. Overall, these results support our hypothesis that cigarette smokers, particularly as they become more involved with cigarette smoking, do more than just smoke cigarettes; they exhibit a less healthy lifestyle as shown by cognitive, behavioral, and motivational dimensions related to cardiovascular health.

Adolescent↗
PubMed1989

Assessment of nuclear anxiety among American students: stability over time, secular trends, and emotional correlates.

Studies of reactions and attitudes toward nuclear war have progressed from the use of anecdotal evidence to multi-item psychological measures. Additional psychometric data and substantive results of the Nuclear Attitudes Questionnaire (NAQ; Newcomb, 1986) are reported here. Data from three independent samples of students from the United States collected in 1984, 1986, and 1987 were compared and contrasted. The 1986 data were obtained immediately following the Chernobyl nuclear power plant accident. Test-retest reliability of the NAQ items and subscales was quite high and comparable among samples and established the across-time stability of the measure. There were several secular trends across years on items and subscales, indicating some increased concern about nuclear power (particularly in 1986), but also a general increase in nuclear concerns, fears, and anxiety. Anticipated sex differences were found on many of the NAQ items and subscales. Correlations between the NAQ subscales and the nine SCL-90-R scales (Derogatis, 1977) were consistent for the 1986 and 1987 samples. In latent variable analyses, a general factor of Emotional Distress was significantly correlated with a general factor of Nuclear Anxiety, as well as specifically with nuclear concern and fear for the future.

Adult↗
PubMed1989

Predicting changes in teenage drug use: the role of intention-behavior discrepancy.

This research investigated the role of intention-behavior discrepancy in predicting changes in drug use by American teenagers. The tested behavior included drinking alcohol, smoking cannabis, and taking hard drugs. Data were collected from 1,177 young adolescents at two time points separated by one year. Two sets of analysis were performed--a multitrait-multimethod latent variable model and longitudinal analyses. The results of longitudinal analyses indicated that, although young adolescents were legally and socially prohibited from engaging in drug-taking activities, some of them intended to use drugs. This discrepancy between behaviors and intentions decreased neither drug-taking behaviors nor intentions to use drugs over time; on the contrary, it increased adolescents' illegal drug use and intention to engage in such behaviors as predicted by Brehm's reactance theory. This discrepancy factor was a better predictor of later drug-taking behavior and positive intentions to use drugs than early intentions alone. The best predictor of later behavior and intentions was prior drug use.

Adolescent↗
PubMed1988

Adolescent drug use and intention to use drugs: concurrent and longitudinal analyses of four ethnic groups.

Concurrent and longitudinal analyses of the associations between intention to use and actual use of substances were examined for 847 adolescents from four different ethnic backgrounds. Five different substances were studied: Cigarettes, alcohol, cannabis, nonprescription medications, and hard drugs. Results showed that: (a) there were significant and consistent relationships between current level of substance use and intention of use for all ethnic groups. However, these measures of association varied considerably among ethnic groups and covered a wide range from .17 for Blacks on use of nonprescription medications to .69 for Hispanics on alcohol consumption; (b) the degree of association between intention and use, as well as ethnic differences gradually decreased over time; and (c) partialling out the effects of previous experimentation with drugs decreased the contribution of intention to predict future drug use to a nonsignificant level for Hispanics, to a moderate degree for Black and Asians, and remained a significant and meaningful contribution for Whites.

Adolescent↗
PubMed1988

Risk factors for substance use: ethnic differences among adolescents.

Risk factors for drug and alcohol use and abuse were studied among Hispanic, black, Asian, and white adolescents. The number of risk factors was a significant correlate of prevalence and heavy use among all adolescents, though the effects were stronger for some drug/ethnic group combinations. For example, the association between the number of risk factors and frequency of hard drug use was substantially smaller for blacks, compared to the other three ethnic groups. Risk factors were causal influences for increasing drug use, while controlling for initial level of use, among Hispanics and whites. However, these effects for blacks and Asians were in the same direction but not significant and were not significantly different from Hispanics and whites. Implications for prevention and intervention are discussed.

Adolescent↗
PubMed1987

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↗
PubMed1987

An 8-year study of multiple influences on drug use and drug use consequences.

Multiple long-term influences on young adult drug use and abuse were tested within an interactionist perspective using latent-variable causal models. Intrapersonal influences included early drug use and social conformity. Proximal interpersonal influences were captured by perceived peer drug use, perceived adult drug use, and family disruption. More distal influences included perceptions of community approval or disapproval for drug use. Outcome measures included not only use of drugs but also disruptive drug use (getting high at work or school) and self-admitted problems with drugs. Data were obtained from 654 participants at three equally spaced time points during an 8-year longitudinal study that began when the subjects were in junior high school. Confirmatory factor analyses were used to test the adequacy of the hypothesized measurement model. Subsequently, a structural equation, or path model, was used to examine the across-time relations among the latent and manifest variables. Stability effects were found for all repeatedly measured latent variables across the 4-year spans. Social conformity strongly influenced other latent variables across time. Early drug use and perceived adult drug use were prominent predictors of young adult drug use, whereas prior drug use predicted disruptive drug use and a lack of social conformity predicted problems with drug use. Early adult alcohol use predicted later disruptive drug use and problems with drug use. Perceived adult drug use generally influenced later alcohol use, whereas peer drug use influenced later cannabis and hard-drug use. Implications for prevention and treatment using a multicausal interactionist perspective are discussed.

Adult↗
PubMed1987

Purpose in Life Test assessment using latent variable methods.

A psychometric assessment was conducted on a slightly revised version of the Purpose in Life Test (PIL-R). Factor analyses revealed a large general factor plus four primary factors comprising lack of purpose in life, positive sense of purpose, motivation for meaning, and existential confusion. Validity models showed that the PIL-R was positively related to a construct of happiness and was negatively related to suicidality and meaninglessness. Reliability estimates ranged from 0.78 to 0.86. The revised version can be presented compactly and may be less confusing to subjects than the original PIL.

Adult↗
PubMed1987

Substance abuse and psychosocial risk factors among teenagers: associations with sex, age, ethnicity, and type of school.

The search for the one causal influence to account for youthful drug use has always failed. An alternate approach is advocated and tested that relates exposure to and impact of various types of psychosocial risk factors to understanding substance use. Data were obtained from 2,926 students in the 7th, 9th, and 11th grades. Twelve risk factors were selected and tested. These 12 variables were able to explain over 50% of the variance in a measure of general drug use. A unit-weighted, summed index of risk factors was linearly related to use and abuse (heavy use) of cigarettes, alcohol, cannabis, cocaine, hard drugs, and a composite substance use score. Differential exposure to and impact of risk factors on drug-taking behaviors were tested for differences by sex, age, ethnicity, and type of school attending. Patterns of exposure were somewhat different than patterns of vulnerability and impact, and can partially account for the status-group differences in drug use.

Absenteeism↗
PubMed1987

Cocaine use and psychopathology: associations among young adults.

Cocaine use has been associated with psychopathology in clinic and treatment samples and among chronic, excessive users. These relationships have been tested rarely in general epidemiological samples. This study examines the association between cocaine involvement and numerous measures of psychopathology in general community sample of 739 young adults. There were no sex differences in level of cocaine involvement, nor on associations between cocaine use and psychopathology. There were several small relationships between cocaine use and several indicators of psychopathology (i.e., increased sleep disturbance, decreased panic and phobia symptoms, a lack of purpose in life, increased psychotic proneness). It appears that the severe psychopathology associated with cocaine use often cited in the literature is the result of using clinic or treatment samples or chronic abusers, and that such strong associations are not apparent in the general population of young adults with relatively brief cocaine use careers.

Adult↗