Genetic and Environmental Influences on Pubertal Development: Longitudinal Data From Finnish Twins at Ages 11 and 14.

To study sources of individual differences in pubertal development, the authors fit a sex-limitation common factor model to data reported, at ages 11 and 14 years, by 1,891 twin pairs on items that comprise the Pubertal Development Scale (PDS; A. C. Petersen, L. Crockett, M. Richards, & A. Boxer, 1988). The model divides variation into a general pubertal factor and item-specific variation and, in addition, decomposes it into constituent sources. In both boys and girls, genetic influences made the largest contribution to variance common to PDS items. Genetic and nonshared environmental factors accounted for variation specific to PDS items in boys, whereas for girls, common environmental influences were added for growth spurt and menarcheal status. For both common and item-specific variation, genetic effects were partially sex specific. Subsidiary analyses found accelerated maturation in both boys and girls who at age 14 were reared in father-absent homes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual behavior in young adulthood: A population-based twin study.

Objective: With behavior genetic analyses of data from young adult twins, we evaluated theoretical perspectives that differentially emphasize biological dispositions, social/cultural factors, or universal pathways to explain individual differences in sexual behaviors. Design: We fit biometric sex limitation models to three aspects of sexual behavior reported by 4,925 Finnish twins ages 23-27. Main Outcome Measure: From a postal questionnaire, we obtained self-report information on initiation/abstinence of sexual intercourse, onset age, and number of sexual partners. Results: Genetic and non-shared environmental influences were significant for all three measures. There were trends for common environmental influences on initiation and, in females, age at first intercourse. Some differential effects in males and females were found. Results comparing onset age and number of partners among experienced twins from pairs concordant and discordant for initiation found genetic and environmental influences on initiation/abstinence overlapped those found for the other aspects of sexual behavior. Conclusions: These results document genetic variation in individual differences in sexual behavior of young adults. Incorporating genetic dispositions into integrated models of sexual behavior will facilitate more effective health promotion and risk taking intervention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of state and trait affect on HIV risk behaviors: A daily diary study of MSM.

Objective: To characterize the influence of state and trait affect on HIV risk behaviors. Design: Men who have sex with men (N = 155) completed reports of trait affect and daily reports of affect and sexual behaviors each night for up to 30 days. Main Outcome Measures: Analyses focused on the role of state and trait positive activation (PA), negative activation (NA), anxious arousal (AA), and sexual activation (SA) on sexual risk taking, operationalized as having a sex partner, a partner-related risk composite, and an HIV risk behavior composite. Results: State SA was positively associated with having a sex partner and HIV risk behaviors; trait SA was positively associated with partner-related risk. State AA was negatively associated with having a sex partner and positively associated with HIV risk behaviors. Trait AA had a negative association with partner-related risk and moderated the effects of state AA. State PA was negatively associated with HIV risk behaviors, and trait PA had a main effect on having a sex partner. NA had no significant trait or state effects. Conclusion: These data suggest a role for multiple affective states in sexual risk taking. Models of HIV risk-taking behaviors should be extended to include affective processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic influences on the association between personality risk factors and alcohol use and abuse.

The authors assessed the association of 2 personality dimensions with use and abuse of alcohol in 1,320 twin pairs concordantly reporting nonabstinence at age 18.5 years. The 2 alcohol outcomes differentially relate to the 2 personality dimensions: Alcohol-related problems correlate more highly with social deviance than with excitement seeking (ES), and alcohol consumption correlates more highly with ES than with social deviance. Biometric models fit to the data identified similar patterns in genetic covariance, although differences were more evident in genetic correlations between social deviance and alcohol outcomes than in those for ES. Results suggest that genetic influences underlie the association of personality with alcohol use and subsequent problems and illustrate the utility of informative twin analyses in exploring links between genes, personality, and behavior disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The temporal relationship between alcohol consumption and HIV-medication adherence: A multilevel model of direct and moderating effects.

Previous studies documenting an association between alcohol use and HIV medication nonadherence, have been unable to distinguish between-persons characteristics from within-person characteristics representing the temporally linked effects of alcohol. Hierarchical Linear Modeling (HLM) explored within- and between-person predictors of adherence during the past 14 days, as well as factors that moderate the event-level effects of alcohol consumption among 272 HIV-positive men and women with alcohol problems. On days in which participants drank, they had almost 9 times higher odds of medication nonadherence, with each drink increasing the odds by 20%. The cognitive and alcohol factors had significant between-person effects on adherence. Individuals with strong and rigid beliefs about the importance of strict medication adherence were significantly more affected by each dose of alcohol, while individuals with more alcohol use and problems were less affected by each drink. Regimen complexity increased the effects of having 1 or more drinks. These results highlight the importance of promoting medication adherence among alcohol-using adults, especially among patients with complex regimens or with high confidence and positive attitudes toward HIV medication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship characteristics and sexual risk-taking in young men who have sex with men.

Objective: Young men who have sex with men (MSM), particularly young men of color, are experiencing the largest increase in HIV incidence of any risk group in the United States Epidemiological research suggests that the majority of transmissions among MSM are occurring in the context of primary partnerships, but little research has been done on the processes within these dyads that increase HIV risk behaviors. The aim of this study was to use longitudinal partnership-level data to explore the effects of partner and relationship characteristics on the frequency of unprotected sex within young MSM relationships. Method: One hundred twenty-two young MSM (age 16–20 at baseline) were assessed at three time-points six months apart, with 91% retention at the 12-month follow-up wave. Over 80% were racial/ethnic minorities. At each wave, participants reported on characteristics of the relationships and partners for up to three sexual partners. Hierarchical linear modeling was used for analyses. Results: The largest effect was for considering the relationship to be serious, which was associated with nearly an eightfold increase in the rate of unprotected sex. Other factors that increased risk behaviors included older partners, drug use prior to sex, physical violence, forced sex, and partnership lasting more than six months. Partners met online were not associated with significantly more sexual risk. Conclusions: These data provide insight into the relationship processes that should be addressed in prevention programs targeted at young MSM. Relationships may serve as a promising unit for HIV prevention interventions, although more formative research will be required to address potential logistical obstacles to implementing such interventions. The partner-by-partner analytic approach (i.e., evaluating situational variables associated with several partners for a given participant) holds promise for future HIV behavioral research. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sexual compulsivity, state affect, and sexual risk behavior in a daily diary study of gay and bisexual men.

Researchers have identified a strong link between sexual compulsivity (SC) and risky sexual behavior among men who have sex with men (MSM). Meanwhile, affect/mood has also been connected with negative sexual health outcomes (sexually transmitted infection/human immunodeficiency virus [HIV] transmission, sexual risk, sex under the influence of drugs/alcohol). Given that SC is characterized by marked distress around one's own sexual behavior, affect may play a central role in SC and HIV risk behavior. Data were taken from the Pillow Talk Project, a pilot study conducted in 2008–2009 with 50 highly sexually active MSM (9 or more male sex partners, ≤ 90 days), of which half displayed SC symptoms and half did not. Forty-seven men completed a daily diary online for 30 days (n = 1,060 diary days), reporting on their sexual behavior and concurrent affect: positive activation, negative activation, anxious arousal, and sexual activation. We conducted HLM analyses using daily affect (Level 1, within subjects) and SC and HIV status (Level 2, between subjects) to predict sexual behavior outcomes. Increased negative activation (characterized by fear, sadness, anger, and disgust) was associated with reduced sexual risk behavior, but less so among sexually compulsive MSM. Sexual activation was associated with increased sexual risk taking, but less so among sexually compulsive MSM. Anxious arousal was associated with increased sexual behavior, but not necessarily sexual risk taking. Findings indicate that affect plays key roles in sexual behavior and sexual risk taking; however, the association between affect and behavior may be different for sexually compulsive and non-sexually compulsive MSM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)