ORIGINAL PAPER Social Cognition Variables and Victimization as Predictors of Sexual Debut Among Adolescents in South Africa and Tanzania: A Multi-group SEM Analysis Annegreet Gera Wubs 1 • Leif Edvard Aarø 1,2 • Sylvia Kaaya 3 • Hans Onya 4 • Catherine Mathews 5,6 Ó Springer Science+Business Media New York 2015 Abstract Early sexual debut is common in South Africa and Tanzania, with potentially negative reproductive health outcomes. The role of violence as a predictor of sexual debut was studied, in a context of predictors borrowed from social cognition models. Data were taken from cluster- randomized trials of school-based HIV prevention inter- ventions in three sites in South Africa and Tanzania. Analyses consisted of descriptive statistics and multi-group structural equation modelling. The basic model functioned fairly well for Cape Town, but less well for Mankweng and Dar es Salaam (low R 2 values). Attitudes were the stron- gest predictor of intention. Adding socio-demographic variables to the model did not reduce the associations much and neither did subsequent inclusion of violence. Sexual debut was strongly associated with victimization; adding violence also substantially increased R 2 for sexual debut. Besides social cognition factors, intimate partner violence should be addressed in future research on reproductive health interventions for adolescents. Keywords HIV prevention Á Intimate partner violence Á Adolescents Á Theory of planned behaviour Á Multi-group SEM analysis Introduction In South Africa and Tanzania at least half of young people are sexually active by age 16 [1, 2]. Early first intercourse is associated with violence; the younger a person is at first intercourse, the more likely it is that force is involved [3]. Studies on forced sex in South Africa and Tanzania found that 40 and 28 % of women, respectively, reported that their first sexual intercourse was forced [3]. Early sexual debut carries a higher risk for a number of reproductive health problems: teenage pregnancy, high number of sexual partners, inconsistent condom use, and HIV transmission, to name a few [4]. In order to effectively focus preventive efforts regarding sexual- and reproductive health of young people, it is important to determine what factors influence sexual debut. This study examines psychosocial factors in particular, such as attitudes and social norms, as well as the influence of violence on early sexual debut. Social cognition theories on behaviour aim to explain and predict human behaviour. The Theory of Planned Behaviour (TPB) [5] is one of the most applied and studied social cognition models. The theory assumes that intentions are the strongest and most direct predictors of behaviour. Intentions are influenced by three factors: attitudes, sub- jective norms and perceived behavioural control. These factors are formed by beliefs about consequences of be- haviour (behavioural beliefs), about beliefs related to what & Annegreet Gera Wubs annegreet.wubs@uib.no 1 Department of Health Promotion and Development, Faculty of Psychology, University of Bergen, Postboks 7800, 5020 Bergen, Norway 2 Division of Mental Health, Norwegian Institute of Public Health, Oslo, Norway 3 Department of Psychiatry, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania 4 Health Promotion Unit, School of Health Sciences, University of Limpopo, Polokwane, South Africa 5 Health Systems Research Unit, South African Medical Research Council, Cape Town, South Africa 6 Adolescent Health Research Unit, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa 123 AIDS Behav DOI 10.1007/s10461-015-1087-x