Modeling censored-in-the-middle condom use data.

Many HIV prevention programs seek to reduce the risk of infection through increases in condom use. Condom use is often expressed as a proportion: the number of sexual contacts in which a condom is used divided by the total number of sexual contacts. The distribution of this proportion has several undesirable characteristics-the principal one is bimodality. Bimodality results from excessive numbers of 0% and 100% responses, creating distributions that are censored-in-the-middle. The purpose of this paper is to show how censored condom use data can be usefully modeled using Tobit regression. Tobit regression first transforms observed variable scores into latent variable scores, scores on an unobserved, hypothetical condom use variable, and then the latent variable scores are modeled using one or more explanatory variables. Data from the National Institute on Drug Abuse Cooperative Agreement for HIV/AIDS Community-Based Outreach/Intervention Research program for frequency of condom use and number of drug injecting sex partners were used to illustrate the method. We found that for every additional drug injecting sex partner, the probability of using condoms decreased by approximately 1%.

Suicidality patterns and sexual orientation-related factors among lesbian, gay, and bisexual youths.

Three hundred fifty lesbian, gay, and bisexual youths aged 14 to 21 years were questioned about suicidal thoughts and behaviors, families' reactions to youths' sexual orientation, and suicidality among relatives and friends. Results confirmed an association between sexual orientation and suicidality. Nearly half (42%) had sometimes or often thought of suicide; one third (33%) reported at least one suicide attempt. Many related suicidal ideation and suicide attempts to their sexual orientation. Most attempts followed awareness of same-sex feelings and preceded disclosure of sexual orientation to others. One quarter said a family member had made a suicide attempt, and nearly three quarters said a close friend had attempted suicide.

Aspects of mental health among older lesbian, gay, and bisexual adults.

This study examined aspects of mental health among 416 lesbian, gay, and bisexual adults aged 60 to 91 years old, attending social and recreational programs. Mental health indicators were perceived mental health status; self-esteem; internalized homophobia; loneliness; alcohol and drug abuse; and suicidality. Better mental health was correlated with higher self-esteem, less loneliness, and lower internalized homophobia. Compared to women, men reported significantly more internalized homophobia, alcohol abuse, and suicidality related to their sexual orientation. Less lifetime suicidal ideation was associated with lower internalized homophobia, less loneliness, and more people knowing about participants' sexual orientation.

Social support networks of lesbian, gay, and bisexual adults 60 years of age and older.

The social support networks of 416 lesbian, gay, and bisexual adults aged 60 to 91 years were examined. Participants averaged 6 people in their support networks, most of whom were close friends. The gender composition of support networks was greatly influenced by the gender of the respondent. Most support network members knew about respondents' sexual orientation. The most common type of support provided by close friends and social acquaintances was socializing support, and the most common support provided by partners, siblings, and other relatives was emotional support. The sexual orientation, gender, and age of network members did not influence respondents' satisfaction with the support received. Participants were more satisfied with support from those who knew of their sexual orientation. The more satisfied respondents felt with the support they received, the less lonely they felt. Those living with domestic partners were less lonely and rated their physical and mental health more positively than those who lived alone.

Peer victimization and attitudes about violence during early adolescence.

Examined roles for attitudes about violence as a possible influence on the frequency of commonplace aggression toward peers among 1,033 adolescents in the 7th through 9th grades. The peer victimization measure adapted from prior studies yielded 2 reliable subscales: Victimization of Self and Victimization of Others. The attitudes and beliefs measure modified for this study yielded 3 reliable subscales (Aggression Is Legitimate and Warranted, Aggression Enhances Power and Esteem, One Should Not Intervene in Fights). These attitudes were meaningfully related to self-reported aggression toward peers but less clearly related to self-victimization. The attitudes were plausible mediators of the relation between gender and aggression toward others and appeared influential for both boys' and girls' aggression toward peers. Little support was found for these attitudes moderating the relation between self-victimization and aggression toward others, yet a clear link between victimization of self and aggression toward others was evident. Results support an emphasis on attitudes and values regarding aggression in violence-prevention efforts, as well as direct efforts to reduce self-victimization.

Lesbian, gay, and bisexual youth and their families: disclosure of sexual orientation and its consequences.

Lesbian, gay, and bisexual youngsters, aged 14-21 and living at home, were studied for patterns of disclosure of sexual orientation to families. Three-quarters had told at least one parent, more often the mother than the father. Those who had disclosed were generally more open about their sexual orientation than those who had not, and few of the nondisclosed expected parental acceptance. Those who had disclosed reported verbal and physical abuse by family members, and acknowledged more suicidality than those who had not "come out" to their families.

Genetic and environmental contributions to the acquisition of a motor skill.

Practice, with feedback, is a fundamental variable that influences the aquisition of motor skills: with it, everyone improves, but some improve more than others. This simple fact has led to frequent debate over the relative importance of genetic and environmental influences on motor learning. In principle these factors could influence subjects' initial level of proficiency, their rate of improvement or their final level of attainment. The problem has been investigated using the rotary pursuit (RP) task, in which subjects learn to track a rotating target with a stylus; this is a factorially pure task which is relatively unaffected by cognitive or verbal factors. Earlier studies of twins reared together indicated that heredity was the primary factor responsible for individual differences in motor skill. Here we have studied learning in a sample of monozygotic (MZA) and dizygotic (DZA) twins who had been reared apart. Heritability of performance was high even in the initial phase, and increased with practice. The rate of learning was also significantly heritable. We propose that the effect of practice is to decrease the effect of environmental variation (previous learning) and increase the relative strength of genetic influences on motor performance.

Life events and personality in late adolescence: genetic and environmental relations.

The relationship between life events and personality was investigated in the Minnesota Twin/Family Study, using 216 monozygotic and 114 dizygotic 17-year-old male twin pairs. Participants completed a life events interview designed for adolescents and the Multidimensional Personality Questionnaire. Life events were categorized into three types: life events to which all members of a family would be subject and those affecting an individual, which can be broadly construed as either nonindependent or independent. Univariate genetic model fitting indicated the presence of significant genetic effects (h2 = 49%) for nonindependent nonfamily life events but not for the other two types of life events. Bivariate genetic model fitting further confirmed that the significant phenotypic correlation between nonindependent life events and personality is in part genetically mediated. Specifically, the findings suggest that genetically influenced individual differences in constraint play a substantial role in life events whose occurrence is not independent of the individual's behavior.

Traits and metatraits: their reliability, stability, and shared genetic influence.

Metatraits measure individual differences in construct relevancy, whereas traits measure individual differences in construct extremity. Twenty-four traits and metatraits were examined in this study using 157 pairs of identical twins reared together, 95 pairs of identical twins reared apart, 211 pairs of fraternal twins reared together, and 228 pairs of fraternal twins reared apart obtained from the Swedish Adoption/Twin Study of Aging (see N. L. Pedersen et al., 1991). Reliability and stability analyses of the metatraits revealed generally lower reliability and stability across time compared to traits. Quantitative genetic analyses of the relationship between traits and metatraits indicated that approximately 69% of the metatrait's genetic variance is shared with the trait, with 31% of its genetic variance unique to the metatrait. These results suggest that metatraits provide a useful additional view of personality.

A multiyear analysis of changes in AIDS concerns and homophobia on a university campus.

The authors studied changes in personal concerns and fears about AIDS and homophobia from 1985 to 1992 among four samples of heterosexual undergraduate students on a university campus. Over time, students' self-reported knowledge about AIDS increased, as did personal worry about HIV infection. Interest in attending an educational program increased initially, then leveled off, and fear of casual contact with people with AIDS decreased. The study findings showed no changes in homophobia. High fear of AIDS was associated with being less informed, having greater concern about infection, and being more homophobic.

Dimensions of occupations: genetic and environmental influences.

This study investigates the dimensions of occupation, and distances between occupational categories, by using intra-pair differences in adult occupational position for identical twins reared apart. Status and farm dimensions of occupation were identified. The results validate the use of occupational status as a dimension of occupational position. The causes of individual differences for the derived status dimension were also evaluated, based on groups of identical and fraternal twins reared apart or together. Genetic effects accounted for a substantial amount of the variance in occupational status for men, while shared and non-shared environmental effects were of about equal importance. For women, genetic effects were less important, and shared and non-shared environmental effects accounted for more of the variation. The results confirm that genetic effects are important sources of the familial resemblance often found for occupational status for men.

Genetic and environmental influences on perceptions of organizational climate.

Genetic and environmental influences on perceptions of organizational climate were assessed by using a 4-group twin design. Data were obtained as part of the Swedish Adoption/Twin Study of Aging. The Work Environment Scale (WES) was used to evaluate perceptions of organizational climate. A measure of job satisfaction was also used to evaluate the effects of genes and environments on job attitudes. Maximum likelihood estimates of genetic and environmental influence suggested significant genetic effects for Supportive Climate--1 factor resulting from a factor analysis of the WES--but not for a second factor, Time Pressure. Significant environmental effects were found for both Supportive Climate and Time Pressure. Genetic effects were not significant for job satisfaction. The relevance of findings to organizational climate research and personnel selection are discussed.

Lesbian, gay, and bisexual youth in community settings: personal challenges and mental health problems.

Studied 194 lesbian, gay, and bisexual youth aged 21 and younger who attended programs in 14 community centers to determine the personal challenges they face due to their sexual orientation and their responses to these stresses. First awareness of sexual orientation typically occurred at age 10, but disclosure to another person did not occur until about age 16. There was much variability in sexual behavior, and many youths reported both same-sex and opposite-sex sexual experiences. Although most had told at least one family member about their sexual orientation, there remained much concern about family reactions. Suicide attempts were acknowledged by 42% of the sample. Attempters significantly differed from nonattempters on several milestones of sexual orientation development, social aspects of sexual orientation, parents' knowledge of sexual orientation, and mental health problems.