Depression, conduct disorder, smoking and alcohol use as predictors of sexual activity in middle adolescence: a longitudinal study

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=rhpb20 Download by: [Tampere University] Date: 20 September 2016, At: 00:33 Health Psychology and Behavioral Medicine An Open Access Journal ISSN: (Print) 2164-2850 (Online) Journal homepage: http://www.tandfonline.com/loi/rhpb20 Depression, conduct disorder, smoking and alcohol use as predictors of sexual activity in middle adolescence: a longitudinal study Riittakerttu Kaltiala-Heino, Sari Fröjd & Mauri Marttunen To cite this article: Riittakerttu Kaltiala-Heino, Sari Fröjd & Mauri Marttunen (2015) Depression, conduct disorder, smoking and alcohol use as predictors of sexual activity in middle adolescence: a longitudinal study, Health Psychology and Behavioral Medicine, 3:1, 25-39, DOI: 10.1080/21642850.2014.996887 To link to this article: http://dx.doi.org/10.1080/21642850.2014.996887 © 2015 The Author(s). Published by Taylor & Francis Published online: 09 Jan 2015. Submit your article to this journal Article views: 823 View related articles View Crossmark data Depression, conduct disorder, smoking and alcohol use as predictors of sexual activity in middle adolescence: a longitudinal study Riittakerttu Kaltiala-Heino a,b *, Sari Fröjd c and Mauri Marttunen d,e a School of Medicine, University of Tampere, Tampere, Finland; b Department of Adolescent Psychiatry, Tampere University Hospital, Tampere, Finland; c School of Health Sciences, University of Tampere, Tampere, Finland; d Faculty of Medicine, National Institute for Health and Welfare, University of Helsinki, Helsinki, Finland; e Department of Adolescent Psychiatry, Helsinki University Hospital, Helsinki, Finland (Received 5 October 2014; accepted 7 December 2014) Objective: To study associations between emotional and behavioural symptoms and later engagement in sexual behaviours in middle adolescence. Materials and methods: All ninth graders in two Finnish cities were recruited to respond to a questionnaire focusing on mental health and disorders, health behaviours and risk and protective factors (T1), and a follow-up survey two years later (T2). The baseline sample (94.4% of all eligible) comprised 1609 girls and 1669 boys, with mean age of 15.5 years (SD 0.39). A total of 2070 adolescents completed the survey at both T1 and T2. The response rate of the final sample was 63.1% (2070/3278). Of the respondents, 56.6% were girls. Experience of intercourse and number of partners for intercourse were elicited at age 17. Depression was measured with the 13-item Beck Depression Inventory, conduct disorder with the Youth Self-Report, and smoking and alcohol consumption with questions widely used in Finnish adolescent health surveys. The data were analysed using cross-tabulation with chi square statistics for classified variables and t-test for continuous variables. Logistic regression was used to study multivariate associations. Results: Depression, conduct disorder, smoking and drinking at age 15 were associated with having experienced intercourse by age 17 (odds ratios (ORs) 1.8–10.3) and with multiple partners for intercourse by age 17 (ORs: 2.4–4.7) among girls. In boys, frequent alcohol use and smoking at age 15 (ORs: 2.2 and 4.6) were associated with experience of intercourse by age 17, and these and conduct disorders at age 15 with multiple partners for intercourse by age 17 (ORs: 2.8–3.2). Conclusion: Emotional and behavioural disorders in middle adolescence are associated with sexual activity and risk-taking sexual behaviours later in the developmental phase. Keywords: depression; conduct disorder; substance use; sexual behaviour; adolescence Introduction In adolescence, sexual development accelerates, with rapid changes to adolescentśbodies. Young people’s experiences of a changing body, sexuality and developing gender identity affect intrapersonal, relational and societal interactions (Romeo & Kelley, 2009). First intercourse is often characterized as sexual debut, and, when occurring during adolescent development, is seen both as normative development and as a form of problem behaviour (Madkour, Farhat, Halpern, Godeau, & Gabhainn, 2010). Intercourse exposes the adolescent to the risk of unwanted © 2015 The Author(s). Published by Taylor & Francis *Corresponding author. Email: merihe@uta.fi This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ Licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Health Psychology and Behavioral Medicine, 2015 Vol. 3, No. 1, 25–39, http://dx.doi.org/10.1080/21642850.2014.996887 pregnancy and sexually transmitted diseases, which are more likely with sexual initiation at younger ages (Edgardh, 2000,2002; Kotchick, Shaffe, & Forehand, 2001;O’Donnell, O’Donnell, & Stueve, 2001). Due to the physical and emotional immaturity of the adolescents, the consequences of these are also likely to be particularly harmful. The vast majority of adolescents across Western countries experience intercourse before the age of 20, but of adolescents aged 15, only one in ten to a third of girls and one in five to a third of boys report having experienced intercourse in European countries and the USA (Eaton et al., 2010; Hubert, Bajos, & Sandfort, 1998; Madkour et al., 2010). During early and middle adolescence, empirical studies have associated sexual debut and risktaking sexual behaviours with a variety of problem behaviours, such as substance use, delinquency and school-related problems, and with negative family factors such as low socio-economic, not living with both parents, family disruption and inadequate parental control (Kotchick et al., 2001; Madkour et al., 2010; Wight, Williamson, & Henderson, 2006). Adolescents may engage in sexual behaviours for negative reasons such as peer pressure or pressure from romantic partner, substance abuse or negative family circumstances, or as an attempt to achieve transition to adulthood. Hence, sexual debut may rather become a negative life event than represent a favourable transition step towards adulthood (Dickson, Paul, Herbison, & Silva, 1998; Goodson, Evans, & Edmundson, 1997; Kotchick et al., 2001; Madkour et al., 2010; Rosenthal, Smith, & de Visser, 1999; Wight et al., 2006). Early coitarche has been associated with childhood and adolescent conduct disorders that also tend to intensify after sexual debut. Depression, suicidality and various risk-taking behaviours are more common among sexually active middle adolescents, not to mention early adolescents. Substance use disorders, antisocial behaviour and schizophrenia but also depression in late adolescence have been associated with risk-taking sexual behaviours and early sexual debut, and adolescents with severe mental disorders have retrospectively reported early coitarche (Hallfors et al., 2004; Heidmets et al., 2010; Ramrakha, Caspi, Dickson, Moffitt, & Paul, 2000; Tubman, Windle, & Windle, 1996). In a large middle adolescent sample, depression (KaltialaHeino, Kosunen, & Rimpelä, 2003) and bulimia (Kaltiala-Heino, Rissanen, Rimpelä, & Rantanen, 2001) were the more common the more advanced sexual experiences the adolescents reported. This held true among both girls and boys, and when pubertal timing, age, family structure and socioeconomic status were controlled for. Moreover, depression was more common the greater the number of partners the adolescents reported for intercourse (Kosunen, Kaltiala-Heino, Rimpelä, & Laippala, 2003). Early maturing adolescents experience intercourse younger and engage in risk-taking sexual behaviour more frequently than their peers whose maturing is average or late (Downing & Bellis, 2009; Edgardh, 2002; Ethier et al., 2006). Early puberty is also associated with both emotional and behavioural disorders among adolescent girls and boys (Kaltiala-Heino, Koivisto, Marttunen, & Fröjd, 2011; Kosunen et al., 2003). Therefore, it is important to control for pubertal timing when associations between mental disorders and sexual behaviour are studied among adolescents. Hallfors, Walter, Bauer, Ford, and Halpern (2005) reported that sexual activity in adolescence was predictive of later depression, but not vice versa. Otherwise, earlier studies that have associated sexual debut during adolescent development with mental disorders have mainly been crosssectional or have surveyed young adults retrospectively (Hallfors et al., 2004; Heidmets et al., 2010;Kotchick et al., 2001; Madkour et al., 2010; Ramrakha et al., 2000; Tubman et al., 1996; Wight et al., 2006). In order to better understand the role of mental disorders in adolescent sexual behaviours, longitudinal associations need to be studied in follow-up data. Emotional and behavioural disorders greatly overlap in adolescence, but research on mental disorders and sexual behaviours has mainly not taken this into account but has focused on one type of disorders at a time. 26 R. Kaltiala-Heino et al. The aim of this study was to analyse longitudinal and concurrent associations between emotional and behavioural disorders and sexual behaviour in middle adolescent population. Given the existing findings that more advanced sexual experiences in early and middle adolescence are cross-sectionally associated rather with poor than positive mental health, we hypothesized that internalizing and externalizing symptoms earlier in adolescent development would predict experience of intercourse and risk-taking sexual experiences later during the developmental phase. In more detail the study questions were (1) Are depression, conduct disorder and substance use at age 15 predictive of having experienced intercourse by age 17? (2) Are depression, conduct disorder and substance use at age 15 predictive of having experienced intercourse with multiple partners by age 17? Materials and methods Study samples and procedures This study is part of an ongoing prospective cohort study, the Adolescent Mental Health Cohort (AMHC) study conducted in two Finnish cities, Tampere (200,000 inhabitants) and Vantaa (180,000 inhabitants). Data collection, procedures and measures of the study have been reported in detail elsewhere (Fröjd, Marttunen, Pelkonen, von der Pahlen, & Kaltiala-Heino, 2006; Ritakallio, Koivisto, Pelkonen, Marttunen, & Kaltiala-Heino, 2008). Briefly, a school survey completed by the ninth graders in all Finnish-speaking secondary schools in the two cities was arranged for data collection at T1. During a school lesson and under the supervision of a teacher subjects completed a person-identifiable survey. Another opportunity to participate was offered in the school for those absent from school on the original survey day, followed by a postal survey twice if still not reached. Eligible participants at T2 were students who had participated at T1. We organized school-based surveys at T1 in upper secondary schools and vocational schools followed by postal survey finally by offering the survey by Internet. The subjects of the present study were students responding to a survey conducted during 2002– 2003 (T1) and at two-year follow-up during 2004–2005 (T2). The baseline sample (94.4% of all eligible) comprised 1609 girls and 1669 boys. The mean age was 15.5 years (SD 0.39). Of the respondents, 71% were living in two-parent families. The distribution of the subjectśparentś highest education was (father/mother): 16%/13% basic compulsory education only, 40%/30% basic compulsory education and vocational school, 17%/31% upper secondary school with or without vocational school, and 28%/26% academic degree (Fröjd et al., 2006).A total of 2070 adolescents completed the survey at both T1 and T2. The response rate of the final sample was 63.1% (2070/3278). Of the respondents, 56.6% were girls. The mean age at T2 was 17.6 years (SD 0.4). Measures Sexual behaviour Sexual experiences were elicited at age 17 by asking “Have you ever had sexual intercourse?” (yes/no), and further by asking “With how many partners have you had sexual intercourse?” (one/two/three/four/five or more). In the analyses, the number of partners was dichotomized to five or more/none to four, with five or more in this age indicating risk-taking sexual behaviour. Earlier Finnish research on adolescent sexual behaviour has similarly used five or more partners to intercourse as indicator of risk-taking sexual activity in middle adolescence (Kosunen et al., 2003). Health Psychology and Behavioral Medicine 27 Depression A Finnish modification of the 13-item Beck Depression Inventory (BDI) (Raitasalo, 2007)was used to assess depression at ages 15 and 17 (Beck & Beck, 1972; Beck, Rial, & Rickels, 1974). Brief BDI is a widely used self-report scale measuring the severity of depressive symptoms, and its reliability and validity are good (Bennett et al., 1997). The BDI has been shown to be appropriate for measuring depression in adolescents in population studies (KaltialaHeino, Rimpelä, Rantanen, & Laippala, 1999; Raitasalo, 2007). Each item is scored 0–3 according to the severity of the symptom. Sum scores of 13 items (range 0–39) were dichotomized to no/ mild depression (scores 0–7), and moderate/severe depression (scores 8–39) (Beck & Beck, 1972). In this study, we classify those scoring 8 or more as presenting with depression, or being depressed. The cut-point of 8 predicts a diagnosis of depression by structured interview Schedules for Clinical Assessment in Neuropsychiatry with good sensitivity (0.93) and specificity (0.88) (Fountoulakis et al., 2003). Frequent alcohol use Frequency of drinking alcoholic beverages was elicited: “How often do you drink alcoholic beverages?”(once a week or more often/approximately once or twice a month/less often/never). In the analyses we dichotomized alcohol use frequency to once a week or more often vs. less frequently. Those who report drinking once a week or more often are considered frequent alcohol users. Smoking At baseline the adolescents were asked “How many cigarettes, pipes or portions of snuff have you consumed so far?”The response alternatives were none/1/2–50/more than 50. A further question was asked “What best describes your current smoking?”with response alternatives daily/weekly/ less than weekly/has stopped smoking. Based on these two questions, the adolescents were dichotomized to daily smokers (has smoked more than once, reports now smoking daily) vs. those who smoke less than daily or not at all (all other alternatives). At follow-up smoking was elicited as “What best describes your current smoking?”The response alternatives were smoking daily/weekly/less than weekly/has stopped smoking/has never smoked, and in the analyses they were dichotomized to smoking daily vs. less or not at all. Thus, at both ages 15 and 17 we focus on daily smoking. Conduct disorder Conduct disorder was measured by the delinquency and aggression scales of the Youth SelfReport (YSR) (Achenbach, 1991). The 90th percentile was used as a cut-point to distinguish adolescents with significant conduct problems in this population, separately for girls and boys. Although the YSR is a method based on self-reported symptoms, it has been demonstrated that high scores on the YSR externalizing scale are predictive of clinical conduct disorder diagnosis with considerable sensitivity and specificity (Morgan & Cauce, 1999). In the present data, the cutoff score for being classified as displaying conduct disorder was 23 for girls and 24 for boys at age 15, and 21 for girls and 22 for boys at ages 17. Depression, frequent alcohol use, daily smoking and conduct disorder at ages 15 and 17 were strongly intercorrelated (data not shown). This was taken into account in the multivariate analyses (see below). 28 R. Kaltiala-Heino et al. Covariates Age and pubertal timing were included in the analyses as covariates. Age was calculated from dates of birth and data collection and was used as a continuous variable expressed in years. Pubertal timing was measured by age at menarche/oigarche by asking: How old were you when you first had your periods/experienced ejaculation? The response alternatives were 10 years or less/11/ 12/13/14/15 or older/I have not yet. In the analyses pubertal timing was classified according to age at menarche/oigarche to early (11 years or earlier), normative (12–13 years) and late (14, 15 or later and not yet). Attrition Altogether 28% of the girls and 46% of the boys responding to the baseline survey dropped out of follow-up. Not responding at follow-up was associated with increased depression, conduct disorder and substance abuse behaviours in the baseline survey (Fröjd, Kaltiala-Heino, & Marttunen, 2011; Kaltiala-Heino et al., 2011). Responding was not associated with pubertal timing in girls, whereas non-normative pubertal timing was associated with lower probability of responding in boys (early 50%, normative 59%, late 49%; p= .001). Higher age was associated with lower probability of responding (p< .001). Statistical analyses Frequency distributions of all variables studied are given. Bivariate associations between sexual behaviour at age 17 (having experienced intercourse, having had intercourse with five or more partners) and the mental health variables studied as well as with the covariates were studied using cross-tabulation with chi square statistics for classified variables and t-test for continuous variables. We used multivariate logistic regression analyses to investigate the associations. Having had intercourse at age 17 and having had intercourse with five or more partners at age 17 were used in each turn as the dependent variable. Independent variables used were depression, daily smoking, frequent alcohol use and conduct disorder at ages 15 and 17. First, depression at 15 and at 17 (and similarly: daily smoking at 15 and 17, frequent alcohol use at 15 and 17, conduct disorder at 15 and 17) were entered into the analysis controlling for age and age of menarche/ oigarche. Because depression, daily smoking, frequent alcohol use and conduct disorder are likely to be intercorrelated, in the next phase all of these at age 15 were entered simultaneously into the logistic regression analysis, controlling for age and age at menarche/oigarche. Finally, the role of current depression, daily smoking, frequent alcohol use and conduct disorder was controlled for by adding these into the analyses at age 17. The results of the logistic regression analyses are reported giving Odds ratios (ORs) with 95% confidence intervals (95% CI).The goodness of fit of the logistic regression models was tested with Hosmer–Lemeshow goodness-of-fit test. All the analyses were carried out separately for girls and boys. Ethical considerations The study was granted approval by the Ethics Committee of Pirkanmaa Hospital District. The subjects gave written informed consent after being informed about the study and the voluntariness of participation. Their parents were informed in advance by letter, but parental consent was not obtained because the Finnish legislation on medical research allows minors from 15 years to consent alone. Health Psychology and Behavioral Medicine 29 Results A greater proportion of girls than of boys had experienced intercourse (p< .001) and reported five or more partners for intercourse by age 17 (p= .009). Depression was more common among girls both at age 15 (p< .001) and at age 17 (p= .001). Frequent alcohol use did not differ by sex at age 15, but at age 17 boys reported frequent alcohol use more often than girls (p= .001). Daily smoking was equally common in both sexes at both time points (Table 1). Table 1. Distribution of sexual behaviours, depression, frequent alcohol use and daily smoking at ages 15 and 17, and age at menarche/oigarche as well as mean (s.d.) age at baseline among the participants of the AMHC study (%). Girls (n= 1167) Boys (n= 903) Has experienced intercourse at age 17 Yes 57.6 42.0 No 39.9 51.9 Missing 2.5 6.1 Has experienced intercourse with five or more partners at age 17 Yes 14.5 11.0 No 83.0 82.9 Missing 2.5 6.1% Depression at age 15 Yes 11.8 6.0 No 88.0 93.5 Missing 0.5 0.6 Depression at age 17 Yes 10.3 6.3 No 89.5 92.8 Missing 0.2 0.9 Frequent alcohol use at age 15 Yes 9.1 10.9 No 90.6 88.9 Missing 0.3 0.2 Frequent alcohol use at age 17 Yes 15.9 26.0 No 83.7 73.1 Missing 0.4 0.9 Daily smoking at age 15 Yes 20.4 19.7 No 78.7 79.1 Missing 0.9 1.2 Daily smoking at age 17 Yes 25.4 25.6 No 74.1 73.5 Missing 0.4 0.9 Age at menarche/oigarche 11 or less 19.7 17.5 12–13 63.3 57.6 14 or more/not yet 16.7 20.7 Missing 0.3 4.2 Age at baseline (in years) mean (s.d.) 15.5 (0.36) 15.5 (0.36) Note: As conduct disorder was defined as the 90th percentile of the sum score of CBCL delinquency + aggression scales, its prevalence is always 10%. 30 R. Kaltiala-Heino et al. Bivariate analyses Of early maturing boys, 60.0% had experienced intercourse at age 17, compared to 46.2% of normative maturers and 28.2% of late maturers (p< .001). Early maturing boys also more often reported having had five or more partners for intercourse at age 17 (19.6% vs. 10.8% vs. 4.8%, p< .001). Among girls, experience of intercourse was more common the earlier they had experienced menarche (66.5% vs. 61.3% vs. 43.0%, p< .001), and so was having had five or more partners for intercourse (25.7% vs. 13.8% vs. 4.6%, p< .001). Among girls, experience of intercourse at age 17 was not associated with age at baseline. Among boys, intercourse by age 17 was associated with slightly older age at baseline (15.53 (0.34) vs. 15.46 (0.36) years, p= .003). Having had five or more partners by age 17 was not associated with age at baseline in either sex. Experience of intercourse and reporting five or more partners for intercourse were more common among those girls and boys who had presented with conduct disorder, reported daily smoking or frequent alcohol use at age 15. In girls, these experiences were also more common among those who had suffered depression at age 15. Current depression, conduct disorder, daily smoking and frequent alcohol use were similarly associated with experience of intercourse as well as with reporting five or more partners for intercourse at age 17 among girls, and all except current depression also among boys (Table 2). Table 2. Experience of intercourse at age 17, and reporting five of more partners for intercourse by age 17, according to depression, daily smoking, frequent alcohol use and conduct disorder at ages 15 and 17 among Finnish girls and boys (%). Girls Boys Has experienced intercourse at age 17 years (%) Five or more partners for intercourse lifetime (%) Has experienced intercourse at age 17 years (%) Five or more partners for intercourse lifetime (%) pp pp Depression at age 15 <.001 .001 .156 .227 Yes 76.9 23.9 51.9 14.8 No 56.6 13.2 44.0 10.7 Depression at age 17 .03 .009 .408 .082 Yes 67.2 22.5 42.1 17.5 No 58.1 13.7 44.7 10.5 Daily smoking at 15 <.001 <.001 <.001 <.001 Yes 93.9 39.5 78.9 29.2 No 50.2 8.2 36.4 6.4 Daily smoking at 17 <.001 <.001 <.001 <.001 Yes 89.9 36.0 74.9 25.5 No 42.6 7.2 34.5 6.0 Frequent alcohol use at 15 <.001 <.001 <.001 <.001 Yes 92.1 44.3 76.4 34.7 No 56.0 11.6 41.0 8.1 Frequent alcohol use at 17 <.001 <.001 <.001 <.01 Yes 89.0 38.8 70.8 24.3 No 53.3 10.2 35.5 6.4 Conduct disorder at 15 <.001 <.001 <.001 <.001 Yes 86.5 12.1 63.4 32.6 No 56.1 36.1 42.7 8.5 Conduct disorder at 17 <.001 <.001 <.001 <.001 Yes 72.2 36.1 63.9 24.4 No 57.0 12.1 42.9 9.3 Health Psychology and Behavioral Medicine 31 Multivariate analyses predicting experience of intercourse When entered into the logistic regression analysis without the other symptoms/behaviours but after controlling for age and age at menarche, depression at age 15 was associated with increased OR for experiencing intercourse by age 17 (OR 2.4, 95% CI 1.5–3.8. p< .001) among girls. Current depression was not statistically significantly associated with intercourse (Hosmer–Lemeshow goodness of fit 0.830). Conduct disorder at age 15 was associated with experience of intercourse by age 17 (OR 4.0, 95% CI 2.2–7.1, p< .001), and current conduct disorder was also statistically significantly associated with experience of intercourse (OR 1.9, 95% CI 1.2–3.1, p = .01) (HL 0.355). Both past (OR 5.8, 95% CI 3.2–10.8, p< .001) and present (OR 4.7, 95% CI 3.0–7.6) daily smoking increased the OR for having experienced intercourse at age 17 (HL goodness of fit 0.472), as did past (OR 5.8 (2.7–12.3), p< .001) and present (OR 6.8 (4.0– 11.3), p< .001) frequent alcohol use (HL 0.970). When entered together, and controlling for age and age at menarche, depression, smoking, frequent alcohol use and conduct disorder at age 15 all persisted as associated with having had experience of intercourse at age 17 (Table 3). Adding the current symptoms/behaviours levelled out the predictive association of frequent alcohol consumption at age 15, but also resulted in essentially poorer goodness of fit of the model (Hosmer–Lemeshow goodness of fit 0.02). Among boys, depression at age 15 and at age 17 did not increase the OR of having experienced intercourse at age 17, when entered into a logistic regression model and controlling for age and age at oigarche. Daily smoking at both age 15 (OR 2.9, 95% CI1.7–4.8, p< .001) and at age 17 (OR 3.1, 95% CI2.0–4.9, p< .001) was associated with having had intercourse by age 17 (HL 0.206), as was frequent alcohol use at age 15 (OR 2.5, 95% CI 1.4–4.5, p= .001) and at 17 (OR 3.4, 95% CI2.4–5.0, p< .001) (HL0.430). Conduct disorder at age 15 proved associated with intercourse by age 17 (OR 2.0, 95% CI1.2–3.4), but current conduct disorder was not associated with having experienced intercourse at age 17 among boys (HL 0.221). When independent variables were entered simultaneously, daily smoking at age 15 and frequent alcohol use at age 15 were associated with intercourse by age 17, but depression and conduct disorder at age 15 were not (Table 3). The longitudinal associations between daily smoking and frequent alcohol use at age 15 and intercourse by age 17 persisted when symptoms at age 17 were added to the model (HL for model with all the variables was 0.829). Multivariate analyses predicting multiple partners for intercourse Among girls, previous depression and current depression were not associated with having experienced intercourse with five or more partners at age 17, when entered in a logistic regression model after controlling for age and age at menarche. Past (OR 3.3, 95% CI 2.1–5.2) and present (OR 2.7, 95% CI 1.7–4.4) conduct disorder was associated with reporting five or more partners for intercourse (Hosmer–Lemeshow goodness of fit 0.639), as were past (OR 2.9, 95% CI 1.8–4.5) and present (OR 3.8, 95% CI 2.4–6.0) smoking (HL 0.252) and past (OR 3.6, 95% CI 2.2–5.7) and present (OR 4.2, 95% CI 2.8–6.2) frequent alcohol use (HL 0.686). When all the symptoms and behaviours studied at age 15 were entered into the model simultaneously, and after controlling for age and age at menarche, intercourse with five or more partners by age 17 was among girls predicted by conduct disorder, daily smoking and frequent alcohol use at age 15 (Table 3). These associations also persisted when current symptoms and behaviours were added into the model (Hosmer–Lemeshow goodness of fit for the model including both past and present symptoms: 0.613). Among boys, past (OR 4.0, 95% CI 2.3–7.1) and present (OR 2.0, 95% CI 1.1–3.6) conduct disorder (HL 0.393), past (OR 2.7, 95% CI 1.5–4.9) and present (OR 2.8, 95% CI 1.6–5.1) 32 R. Kaltiala-Heino et al. Rosenthal, D. A., Smith, A., & de Visser, R. (1999). Personal and social factors influencing age at first sexual intercourse. Archives of Sexual Behavior,28, 319–333. Tanner, J. M. (1962). Growth at adolescence. Oxford: Blackwell. Tubman, J. G., Windle, M., & Windle, R. C. (1996). The onset and cross-temporal patterning of sexual intercourse in middle adolescence: Prospective relationships with behavioral and emotional problems. Child Development,67, 327–343. Wight, D., Williamson, L., & Henderson, M. (2006). Parental influences on young people’s sexual behavior: A longitudinal analysis. Journal of Adolescence,29, 473–494. Health Psychology and Behavioral Medicine 39