Arch Sex Behav DOI 10.1007/s10508-014-0265-7

ORIGINAL PAPER

Sexual Initiation and Emotional/Behavioral Problems in Taiwanese Adolescents: A Multivariate Response Profile Analysis Chia-Hua Chan • Te-Tien Ting • Yen-Tyng Chen Chuan-Yu Chen • Wei J. Chen

•

Received: 27 December 2012 / Revised: 24 September 2013 / Accepted: 19 November 2013  Springer Science+Business Media New York 2014

Abstract This study aimed to investigate the relations of adolescent sexual experiences (particularly early initiation) to a spectrum of emotional/behavioral problems and to probe possible gender difference in such relationships. The 10th (N = 8,842) and 12th (N = 10,083) grade students, aged 16–19 years, participating in national surveys in 2005 and 2006 in Taiwan were included for this study. A self-administered web-based questionnaire was designed to collect information on sociodemographic characteristics, sexual experience, substance use, and the Youth Self-Report Form. For the sexually experienced adolescents, their sexual initiation was classified as early initiation (\16 years) or non-early initiation C.-H. Chan
T.-T. Ting
W. J. Chen (&) Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, 17 Xu-Zhou Road, Taipei 100, Taiwan e-mail: [email protected] Y.-T. Chen Department of Behavioral Sciences and Health Education, Emory University, Atlanta, GA, USA C.-Y. Chen
W. J. Chen Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan C.-Y. Chen Institute of Public Health, National Yang-Ming University, Taipei, Taiwan C.-Y. Chen Division of Mental Health and Addiction Medicine, Institution of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli, Taiwan W. J. Chen Department of Psychiatry, College of Medicine and National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan

(16–19 years). Gender-specific multivariate response profile regression was used to examine the relationship between sexual experience and the behavioral syndromes. Externalizing problems, including Rule-breaking Behavior and Aggressive Behavior, were strongly associated with sexual initiation in adolescence; the magnitude of the association increased for earlier sexual initiation, especially for females. As to internalizing problems, the connection was rather heterogeneous. The scores on some syndromes, such as Somatic Complaints and Anxious/Depressed, were higher only for females with early or non-early sexual initiation whereas the score on Withdrawn, along with Social Problems that is neither internalizing nor externalizing, was lower for the sexually experienced adolescents than for the sexually inexperienced ones. We concluded that earlier sexual initiation was associated with a wider range of behavioral problems in adolescents for both genders, yet the increased risk with emotional problems was predominately found in females. Keywords Adolescents
Sexual behavior
Youth Self-Report
Emotional and behavioral problems

Introduction At the turn of the 21st century, the proportion of adolescents having sexual initiation in Western countries has gradually declined (Balaji et al., 2008; Saewyc, Taylor, Homma, & Ogilvie, 2008). In contrast to that, the figures in East Asian countries have been on the rise (Department of Health, 2008; Takakura, Wake, & Kobayashi, 2007). Attitudes toward early sexual initiation and its potential consequences varied across countries (Widmer, Treas, & Newcomb, 1998). For people in East Asia, early initiation of sexual experience is often portrayed as a deviant behavior that is associated with increased

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risk for adverse health outcomes, such as sexually transmitted diseases, unintended pregnancy, substance-use experiences, and social maladjustment (Chiao & Yi, 2011; Lam, Stewart, & Ho, 2001; Ma et al., 2009). Further exploration supported the notion that adolescents with sexual initiation are quite dissimilar in terms of predictors and consequences and the age of sexual initiation appears to be one of indicators to account for possible heterogeneity (Zimmer-Gembeck & Helfand, 2008). One particular concern over early sexual initiation is its impact on adolescents’ emotional or behavioral problems, which are generally classified into internalizing and externalizing patterns. Several observations suggested that both the internalizing and externalizing problems seem to be more common among adolescents with sexual experience, with noticeable gender differences. Specifically, studies suggested strong associations between internalizing problems and female early sexual initiators but little to no association linking internalizing problems to male early sexual initiators (Hallfors, Waller, Bauer, Ford, & Halpern, 2005; Madkour, Farhat, Halpern, Godeau, & Nic Gabhainn, 2010; Martin et al., 2005; Spriggs & Halpern, 2008). In the case of externalizing behavioral problems, the majority of studies showed that these problems were associated with early sexual initiation (McLeod & Knight, 2010; Price & Hyde, 2009; Udell, Sandfort, Reitz, Bos, & Dekovic, 2010). However, it remains unclear whether these associations were present in both genders (McLeod & Knight, 2010; Price & Hyde, 2009) or limited to males (Kapi, Veltsista, Kavadias, Lekea, & Bakoula, 2007; Udell et al., 2010). Furthermore, even within internalizing problems, heterogeneity in the association with sexual experience has been found. For example, some reported that adolescents exhibiting depressive symptoms were more likely to have sexual initiation at earlier ages than those without depressive symptoms (Harris, Duncan, & Boisjoly, 2002; Longmore, Manning, Giordano, & Rudolph, 2004) whereas others suggested those exhibiting a higher level of anxiety werelesslikelytoinitiatesexual activityin adolescence(Caminis, Henrich, Ruchkin, Schwab-Stone, & Martin, 2007). The relations of behavioral or emotional problems to early sexual experience might be further linked to societal attitudes toward adolescent sexuality. Although there is an emerging trend to treat sexuality in adolescence as a developmentally normative phenomenon that emphasizes the integral, positive, and healthy aspects of youth’s sexual experience (Tolman & McClelland, 2011), many East Asian societies continue to treat adolescent sexual initiation as deviant (Chiao & Yi, 2011; Lam et al., 2001; Ma et al., 2009). Sexually experienced adolescents in such societies may exhibit profiles in behavioral problems that are in response to such cultural pressure. A major limitation of previous research is that most of them adopted a single-dimensional (Hallfors et al., 2005;

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Spriggs & Halpern, 2008) or a combination of different scales (Caminis et al., 2007; Madkouret al., 2010; Schofield, Bierman, Heinrichs, Nix, & Group, 2008) rather than a comprehensive instrument that can fully examine adolescent emotional and behavioral problems. To elucidate the entire spectrum of the maladaptive functioning associated with early sexual initiation in adolescents, the Youth Self-Report (YSR) is one instrument commonly used to collect information covering eight emotional and behavioral syndromes from youth themselves (Achenbach, 1995). Nevertheless, previous studies applying this instrument (Kapi et al., 2007; Udell et al., 2010) were limited to comparing the mean difference or the proportion of dichotomized classification for individual syndromes and leaves open the question of whether interdependencies may exist within individual’s response (e.g., individuals who report the experience of ‘‘Anxious/Depressed’’ may be more likely to report the symptoms in ‘‘Withdrawn’’ on the YSR). To address these knowledge gaps, we examined a nationally representative sample of high school-attending adolescents in Grades 10 and 12 in Taiwan with information on YSR. To address potential gender and developmental variation, the aims of this study were to examine (1) whether early sexual initiation was associated with a higher level of emotional/behavioral problems and (2) whether such an association varied across gender and grade. To take into account the possible intra-individual dependency, multivariate response profile regression approach based on generalized linear model and generalized estimating equations (GLM/GEE) was used in this study.

Methods Participants The data for the present study were from the 2005 to 2006 National Survey of Illegal Drug Use among Adolescents (NSIDA), a cross-sectional school survey among school-attending adolescents in Grades 10 and 12. Details of study design, sampling procedure, recruitment, and data collection were reported elsewhere (Chen et al., 2009). Briefly, to ensure that the recruited sample was representative of school-attending adolescents in general, the NSIDA team applied multi-stage random clustering sampling procedure using school types (i.e., middle school, regular high school, and vocational/technical high school) and regions (i.e., according to geographic characteristics, urbanicity level, and populationcomposition)asstrata.Fromthelistofschoolsobtained from the Taiwan Ministry of Education, 133 schools were randomly selected each year. For those schools unwilling to participate (three vocational/technical high schools in 2005, one regular high school, and two vocational/technical high schools in 2006), a replacement school of the same type was selected from the same region. Then, two classes from the 10th and 12th grades within

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each school were randomly selected to participate. All the students in sampled classes were eligible to participate in the study. The written informed consent was obtained from each student prior to study participation. During the study periods in 2005 and 2006, the response rate was 93.2–94.4 % for regular high school and 92– 94 % for vocational/technical high school. The total population comprised 36,485 school-attending adolescents over the two-year assessment. The analyses for the present study were built upon the 2005 and 2006 survey data with complete self-reported sexual experience and frequency collected from 10th and 12th graders in high schools, including 84 regular high schools and 84 vocational high schools. To examine the relationship between adolescent sexual experience and emotional/behavioral problems, we excluded (1) participants whose responses were missing in sexual-related items (n = 70) or reported having their first sex before aged 10 (n = 3); (2) participants whose responses were missing more than three items in emotional/behavioral problems (n = 37); (3) participants whose responses were missing in self-information and drug items (n = 321); and (4) participants who reported having used a ‘‘bogus’’ drug. The final sample consisted of 18,925 participants, with slightly more girls (51.51 %) than boys (48.49 %). Measures The data collection, which took about 20 min (if no experience in a variety of risk behaviors or substance use) to 40 min (if experiencing multiple risk behaviors and poly-substance use) during regular class time, was conducted after the teacher left the classroom, with one or two research assistants present to answer questions, keep order, and assure confidentiality. The survey used a web-based, self- administered, anonymous questionnaire, which has been described in more detail elsewhere (Wang et al., 2005). Upon completion, the participants were offered a set of stationary as incentive (i.e., less than 1 USD). The study was reviewed and approved by the Institutional Review Board of College of Public Health at the National Taiwan University. A battery of pre-coded and pre-worded standardized questionnaires comprised questions about sociodemographic background (gender, age, single-parent family, monetary allowance, and employment experience), development-related behaviors (truancy and sexual experiences), substance use experiences, and emotional/behavioral problems (Chen et al., 2009). Weekly allowance, which represents a proxy measure for family socioeconomic status (Soteriades & DiFranza, 2003), was evaluated on the basis of income given by parents or guardians. Following the definition used in a previous study (Wang et al., 2013), we used the upper tertile of the weekly disposable income, 500 NTD (* 17 USD or *13 Euros), to stratify low income (B500 NTD) and high income ([500 NTD).

For development-related behaviors, such as running away, truancy, and sexual experience, participants were first asked whether they ever had the experience and more detailed questions were then asked about the endorsed experience. In assessing the sexual experience of participants, they were asked whether they had ever had sexual intercourse; if they answered yes, further questions were asked about initiation age, the cumulative number of sexual partners (‘‘With how many persons have you had sexual intercourse during your lifetime?’’), and the gender of sexual partners (i.e., same-sex, opposite-sex, or both). In this study, a sexual initiation before age 16 was considered early based on three reasons. First, the laws are against having sex with minors under the age of 16 in Taiwan. Second, the prevalence of having sexual initiation before age of 18 was less than one fourth among those aged 15–24 in Taipei (Zabin et al., 2009). Third, the definition of early sexual initiation before age 16 has been used in previous studies in other countries (Kuzman, Simetin, & Franelic, 2007; Madkour et al., 2010). Hence, we used age 16 years as a cutoff point to define early sexual initiation: early initiator (onset age\16 years) and non-early initiator (onset age between 16 and 19 years, mid-adolescence). Adolescent emotional and behavioral problems were assessed using the YSR (Achenbach, 1995), rated on a 3-point scale of‘‘not true,’’‘‘somewhat or sometimes true,’’and‘‘very true or often true.’’ Only those items counted in the crossinformant syndromes were used in the questionnaire of this study. It has the following eight narrow-band syndromes: Withdrawn, Somatic Complaints, Anxious/Depressed, Social Problems, Thought Problems, Attention Problems, Rule-Breaking Behavior, and Aggressive Behavior. Part of the narrow-band syndromes are combined into two broad-band syndromes, i.e., Internalizing (Withdrawn, Anxious/Depressed, and Somatic Complaints) and Externalizing (Rule-breaking Behavior and Aggressive Behavior) syndromes. For each syndrome, a participant was considered to reach borderline range with a T score of C65 and clinical range with a T score of [69 (Achenbach, 1995). The present study adopted the Chinese version of YSR (C-YSR), in which a procedure of backtranslation was conducted to ensure the conceptual equivalence of the instrument. The good reliability and validity of YSR are well established and the original questionnaires have been translated into many languages with cross-cultural generalizability (Ivanova et al., 2007) and the C-YSR was found to have good internal consistency in Taiwanese adolescents (Chen et al., 2008).

Data Analysis Since our data were collected with a multistage probability sampling design, survey analyses procedures that allow for differential weights were used to assess the adolescent sexual

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experiences and social-behavioral characteristics (Lee & Forthofer, 2005). We stratified the sample by sex of participants due to vast differences regarding sexual experience across gender. Additionally, given that transition of youth sexual experience is tied to age and school years, the 10th and 12th graders were examined separately. To examine the social-behavioral correlates of three sexual experience groups, multivariable polytomous logistic regression analyses was applied, controlling for potential differences on sociodemographics (e.g., single-parent family, weekly monetary allowance and working experience) and deviant behaviors (e.g., truancy and substance use experiences). Next, the mean scores of each YSR syndrome were compared among different sexual experience groups in terms of effect size, with the sexually inexperienced youth as the reference group. Given a participant’s response on an emotional and behavioral syndrome may not be independent from that on the others, subsequent data analysis then turned to multivariate response profile regression approach based on GLM/GEE to take into account the possible intra-individual dependency. Specifically, the GLM/GEE statistical model consists of three hierarchical levels, following the methods used in previous studies on the same sample of this study (Chen et al., 2008; Chen, Chen, & Chen, 2011). In brief, a baseline model was used to compare mean scores of each syndrome relative to a reference syndrome with a simultaneous adjustment for all of the other syndromes. For an individual, we let each syndrome take a turn as the outcome variable and created a series of dummy variables for the remaining seven syndromes. In this way, every subject had eight records in Y, each with seven dummy variables for syndromes present on the right side. We repeated this model with each syndrome taking a turn as the reference and then chose Thought Problems as the reference for the subsequent analyses because it led to the most consistent beta-estimates of other syndromes (the same direction and more prominent magnitudes). After Thought Problems was selected as the reference syndrome in this study, the second set of the model then examined the group differences in the overall syndrome level by introducing group variables, using the sexually inexperienced group as the reference and simultaneously adjusting for sociobehavioral covariates. With these sociobehavioral covariates unchanged in the third model, the last step was designed to obtain the group-specific pattern by introducing product-terms of group and syndrome variables, thereby appraising the variation relating each initiation-timing group with eight YSR syndromes. Results Sociodemographic Characteristics Of the 10th and 12th grade students recruited in this study, 527 (6.0 %) of 8,842 and 1,107 (11.0 %) of 10,083, respectively,

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reported having a sexual experience. The weighted prevalence of sexual experience, sociodemographic, and behavioral features of the three groups of sexual experience (i.e., sexually inexperienced, non-early initiators, and early initiators) were stratified by grader and gender (see Table 1). For the 10th graders, the weighted prevalence of the early sexual initiation was higher than that of the non-early sexual initiation across gender whereas, for the 12th graders, the trend was reversed, with the weighted prevalence of the non-early sexual initiation much higher than that of the early sexual initiation for both genders. This is likely because the information about the 10th grade non-early sexual initiators was only up to the time point of the survey, i.e., censoring. Nevertheless, the female weighted prevalence of the early sexual initiation for the 10th graders was higher than that for the 12th graders whereas the counterparts of males were similar between the two grades. The early sexual initiation group reported significantly more sexual partners than the non-early sexual initiation group, regardless of gender or grade. Among those with sexual experience, the percentage of adolescents with same-sex sexual partnership seemed to increase from non-early initiators (7.8 and 10.5 % for male 10th graders and 12th graders, respectively, and 14.3 and 11.3 % for female counterparts) to early initiators (14.9 and 10.2 % for male 10th graders and 12th graders, respectively, and 22.0 and 11.8 % for female counterparts), though the differences did not reach statistical significance likely due to the small sample size of non-heterosexual adolescents. Sexual Initiation and YSR Syndromes Comparing the mean scores of each YSR syndrome among different sexual experience groups, the effect sizes that used the same-grade sexually inexperienced adolescents as the reference are shown in Table 2 for the 10th graders and Table 3 for the 12th graders. In general, the effect size increased from the non-early initiation group to the early initiation group, especially for females. When both the 10th and 12th graders were counted together, female early initiators had significantly higher mean narrow-band syndrome scores than the sexually inexperienced in 11 out of 16 YSR syndromes, while the corresponding number for male early initiators was 6 out of 16. Within each sexual initiation group, the effect size of two externalizing behaviors, Rule-breaking Behavior and Aggressive Behavior, were the greatest among the eight syndromes, especially for females, for both grades (Tables 2 and 3). Some syndromes, including Somatic Complaints and Attention Problems, were associated with both female non-early initiation (except Somatic Complaints for the 10th graders) and female early initiation for the 10th graders and 12th graders, but none of them did so with male counterparts. A higher score of Anxious/Depressed was significantly associated with female sexual initiators, regardless

Arch Sex Behav Table 1 Sociodemographic characteristics of the students recruited in national school surveys in Taiwan, by grade and gender (N = 18,925) Variable

Male (N = 4,472)

Sexual debut 10th graders

None (N = 4,207) M (SD)

Weighted prevalence (SE)a

94.2 (0.4)

2.5 (0.3)

3.3 (0.3)

94.7 (0.4)

2.2 (0.3)

3.1 (0.3)

Age (in years)

16.2 (0.7)

16.5 (1.1)

16.4 (1.0)

16.2 (0.6)

16.4 (0.9)

16.3 (0.7)

Age at first sex (in years)

na

16.1 (0.4)

14.2 (1.3)

na

16.1 (0.4)

14.4 (1.0)

No. of sexual partners

na

1.8 (2.2)

na

1.6 (1.5)

n (wt%)a

Female (N = 4,370) Non-early initiators (N = 113) M (SD)

n (wt%)a

Early initiators (N = 152) M (SD)

4.2 (10.1)* n (wt%)a

None (N = 4,108) M (SD)

n (wt%)a

Non-early initiators (N = 112) M (SD)

n (wt%)a

Early initiators (N = 150) M (SD)

2.5 (2.9)* n (wt%)a

Same-sex sexual partner

na

10 (7.8)

21 (14.9)

na

16 (14.3)

29 (22.0)

Single parent

475 (11.4)*

22 (20.0)

31 (19.8)

502 (11.1)*

24 (20.9)

45 (26.8)

Weekly allowance (C500)b

1,671 (39.3)*

76 (64.5)

91 (57.9)

1,316 (31.8)*

61 (50.0)

74 (46.7)

Having a job

306 (7.7)*

34 (33.5)

40 (27.0)

377 (8.1)*

38 (36.7)

54 (33.7)

Truancy

1,162 (28.2)*

66 (60.4)

114 (72.4)

866 (20.8)*

52 (44.1)

106 (72.4)*

Any substance usec

1,913 (45.0)*

90 (78.1)

119 (75.4)

1,593 (38.2)*

93 (83.1)

126 (84.7)

Variable

Male (N = 4,705)

Sexual debut 12th graders

None (N = 4,159) M (SD)

Early initiators (N = 145) M (SD)

None (N = 4,817) M (SD)

Weighted prevalence (SE)a

88.6 (0.6)

8.5 (0.5)

3.0 (0.3)

90.9 (0.4)

7.5 (0.4)

1.6 (0.2)

Age (in years)

17.7 (0.6)

17.8 (0.7)

17.7 (0.7)

17.6 (0.7)

17.7 (0.7)

17.7 (0.7)

Age at first sex (in years)

na

16.9 (0.9)

14.4 (1.3)

na

16.8 (0.8)

14.4 (1.0)

No. of sexual partners

na

2.0 (2.3)

na

1.8 (2.8)

n (wt%)a

Female (N = 5,378) Non-early initiators (N = 401) M (SD)

n (wt%)a

5.0 (9.1)* n (wt%)a

n (wt%)a

Non-early initiators (N = 457) M (SD)

n (wt%)a

Early initiators (N = 104) M (SD)

3.3 (3.1)* n (wt%)a

Same-sex sexual partner

na

34 (10.5)

14 (10.2)

na

53 (11.3)

14 (11.8)

Single parent

437 (10.3)*

71 (15.8)

26 (12.7)

601 (11.8)*

98 (19.7)

33 (34.7)*

Weekly allowance (C500)b

2,107 (49.4)*

241 (57.8)

108 (71.2)*

Having a job

270 (6.1)*

86 (20.7)

29 (19.9)

2,041 (40.4)*

241 (52.2)

62 (56.6)

398 (7.3)*

113 (21.0)

40 (35.7)*

Truancy

1,488 (35.5)*

267 (64.0)

111 (76.7)*

1,231 (24.8)*

254 (55.6)

69 (67.7)

Any substance useb

2,197 (52.3)*

330 (81.1)

126 (90.6)*

2,115 (42.1)*

337 (70.7)

90 (87.1)*

a

The estimated percentages were derived based on complex survey analyses (weighted data with a Taylor series linearization)

b

New Taiwan Dollars

c

Lifetime use of tobacco, alcohol, betel nut, ecstasy, ketamine, marijuana, angel dust, gamma hydroxybutyrate, methamphetamine, flunitrazepam, heroin, or glue

* p\.05 for the design-based Pearson’s v2-test using the same-grade non-early initiation group as the reference

of non-early or early initiation, for both grades and with male non-early initiators only for the 10th grade. Meanwhile, Withdrawn and Social Problems exhibited little association with sexual initiation, irrespective of timing of sexual initiation, gender, and grade level. When each YSR syndrome was dichotomized as either borderline or clinical range, similar patterns among different sexual experience groups for both the 10th (Table 2) and 12th graders (Table 3) were observed, though fewer number of syndromes reached statistical significance. A higher percentage of youth in the borderline range in Rule-breaking Behavior was associated with early sexual initiation for both genders. Meanwhile, borderline elevation on the Anxious/ Depressed and Attention Problems was found in female early sexual initiators, regardless of grade.

To explore whether the type of sexual partner among the sexually experienced adolescents was associated with higher scores in YSR syndromes, we compared the mean syndrome scores of adolescents with same-sex peers or both-sex peers versus those of adolescents with opposite-sex peers (Table 4). Compared to males with opposite-sex sexual partnership, males with same-sex peers had increased scores in four syndromes (Withdrawn, Anxious/Depressed, Social Problems, and Thought Problems) and males with both-sex peers had increased scores in all YSR syndromes, with an effect size ranging from 0.56 to 1.25. Compared to females with opposite-sex sexual partnership, females with same-sex peers also had increased scores in four syndromes (Withdrawn, Somatic Complaints, Anxious/Depressed, Social Problems, and Attention Problems), whereas females with both-sex peers did not

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Arch Sex Behav Table 2 Mean syndrome scores and the percentage with a borderline/clinical range score of the Youth Self Report for the 10th grade students, by gender and timing of sexual debut (N = 8,842) Syndrome

Male None

Female Non-early initiators

(N = 4,207) (N = 113)

Withdrawn

M (SD)

M (SD)

4.01 (3.02)

4.01 (2.98)

Borderline/clinical (%) 6.13/3.45 Somatic complaints

2.21 (2.97)

Borderline/clinical (%) 9.67/6.73 Anxious/depressed

6.71 (5.55)

Borderline/clinical (%) 7.65/4.30 Social problems

3.58 (2.83)

Borderline/clinical (%) 8.63/3.73 Thought problems

ES

3.24 (2.44)

M (SD)

ES

M (SD)

-0.05 4.21 (3.02)

9.87/3.95

10.05/5.28

0.18 2.85 (3.82)

0.22 3.51 (3.62)

14.47/5.36

10.05/3.99

0 .14 7.28 (5.79)

0.10 8.47 (6.25)

7.96/4.42

6.58/2.63

8.33/4.97

-0.12 3.60 (2.96)

10.62/5.31

Non-early initiators

(N = 4,108) (N = 112) a

0.00 3.87 (3.08)

9.73/5.31 7.49 (5.95)

None

(N = 152) a

6.19/3.54 2.75 (3.61)

Early initiators

0.01 3.86 (2.77)

9.87/3.29

7.59/4.09

Early initiators (N = 150)

a

M (SD)

ES

4.06 (2.75)

-0.05 4.11 (3.18)

7.14/4.46 3.98 (3.17) 7.14/5.36 9.76 (5.71) 9.82/5.36 3.87 (2.33) 5.36/5.36

M (SD)

ESa -0.03

6.67/2.00 0.13 5.03 (4.41)

0.42*

11.33/5.33 0.21* 9.94 (6.37)

0.24*

11.33/6.00 0.00 3.88 (2.94)

0.01

4.67/2.67

2.53 (2.04)

2.92 (2.55)

0.19 3.41 (2.59)

0.43* 2.69 (2.13)

3.14 (1.69)

0.21 3.09 (2.20)

0.19

Borderline/clinical (%) 8.34/3.40 Attention problems 6.58 (3.70)

15.04/2.65 6.52 (3.83)

7.89/4.61 -0.02 6.89 (4.07)

7.81/3.31 0.08 7.28 (3.77)

8.93/5.36 7.71 (3.70)

6.00/6.00 0.11 8.00 (3.80)

0.19*

Borderline/clinical (%) 7.08/4.37

7.96/3.54

Rule-breaking behavior

3.12 (2.99)

Borderline/clinical (%) 6.94/5.09 Aggressive behavior

8.64 (6.35)

Borderline/clinical (%) 8.49/4.37 a

3.92 (3.30)

3.95/1.32 0.27* 4.84 (3.70)

5.31/0.88 10.30 (7.33)

5.60/3.26 0.58* 2.54 (2.66)

11.84/3.95

4.67/4.67

0.26* 11.82 (8.01)

5.31/3.54

0.50 9.00 (6.28)

5.92/1.97

6.65/3.51

8.04/5.36 4.11 (2.22) 5.36/4.46 11.26 (5.40) 8.93/8.93

8.67/2.67 0.59* 4.61 (3.18)

0.78*

7.33/4.00 0.36* 11.84 (6.61)

0.45*

6.67/2.00

Effect size was obtained using the sexually inexperienced as the reference group

* p B .016, statistically significant after Bonferroni correction

have increased scores in YSR syndromes except Aggressive Behavior.

early initiators), the reduction on Withdrawn and Social Problems did not reach statistical significance in either one grade or both grades.

GLM/GEE Analysis We then conducted multivariate GEE/GLM analyses to assess the group differences in YSR syndromes using Thought Problems as the reference syndrome and simultaneously adjusting for sociodemographic characteristics and problem behaviors (Table 5). First, consistent with the crude comparisons, the strongest associations with sexual initiation were the two externalizing behaviors (i.e., Rule-breaking Behavior and Aggressive Behavior), regardless of gender, sexual initiation timing, or grade. One noticeable difference was that the magnitude of the association for Aggressive Behavior was greater than that for Rule-breaking Behavior. Meanwhile, female early sexual initiators had significantly increased risk of Somatic Complaints for the 10th graders and Anxious/Depressed symptoms for the 12th graders whereas no such association was observed for female non-early sexual initiators or their male counterparts. Finally, the sexually experienced adolescents had lower scores on Withdrawn and Social Problems than the sexually inexperienced ones, especially for male early initiators, who had significant reduction in both grades. For the remaining three strata (male non-early initiators, female non-early initiators, and female

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Discussion By means of multivariate analyses of a nationally representative sample of adolescents in Taiwan, we found that sexual experience in adolescence was linked to differential risk of emotional/behavioral syndromes. Overall, sexual initiation in adolescence was consistently associated with externalizing problems, including Rule-breaking Behavior and Aggressive Behavior, with the magnitude of the association elevated for earlier timing of sexual initiation and female gender. However, such connection with the internalizing problems was rather heterogeneous. The scores on some syndromes, such as Somatic Complaints and Anxious/Depressed, were higher only for female non-early sexual initiators and female early sexual initiators whereas the score on Withdrawn, along with Social Problems that is neither internalizing nor externalizing, was lower for the sexually experienced adolescents than for the sexually inexperienced ones. Our results may help clarify the conflicting findings from previous research

Arch Sex Behav Table 3 Mean syndrome scores and the percentage with a borderline/clinical range score of the Youth Self-Report for the 12th grade students, by gender and timing of sexual debut (N = 10,083) Syndrome

Male None

Female Non-early initiators

(N = 4,159) (N = 401) M (SD) Withdrawn

4.21 (3.16)

Borderline/clinical (%) 6.92/3.77 Somatic complaints

2.37 (3.21)

Borderline/clinical (%) 9.95/6.64 Anxious/depressed

7.14 (5.71)

Borderline/clinical (%) 7.67/3.99 Social problems

3.73 (2.97)

Borderline/clinical (%) 9.67/4.45 Thought problems

ES

4.19 (3.20)

-0.01

4.99/2.74

ES

3.85 (4.33)

-0.11

10.34/2.76 0.08

2.39 (3.25) 11.03/8.97

8.01 (6.81)

0.15* 7.22 (7.83)

7.73/4.74 7.88/2.99 0.13

3.26 (2.41)

Borderline/clinical (%) 8.80/3.27 Attention problems 6.81 (3.79)

10.97/4.24 7.11 (3.80)

0.08

7.59/2.76 6.73 (3.85)

Borderline/clinical (%) 7.53/4.33

4.74/2.49 4.17 (3.40) 6.48/5.24

Aggressive behavior

9.05 (6.71)

Borderline/clinical (%) 8.39/4.02 a

10.63 (6.81)

ES

4.18 (2.95)

4.16 (2.99)

-0.01

9.69/4.71

8.97/5.03

3.67 (3.53)

4.39 (3.63)

6.37/4.28

8.53/5.91

8.45 (6.12)

9.39 (6.20)

7.99/4.59

7.66/4.81

ESa

4.35 (2.55)

0.06

10.58/3.85 0.20* 4.80 (3.88)

0.32*

9.62/4.81 0.15* 10.91 (6.53) 0.40* 10.58/3.85 0.01

3.74 (2.86)

0.00

8.65/1.92

2.96 (2.35)

0.17* 3.27 (1.73)

0.34*

6.10/6.10 7.13 (3.75)

10.94/5.47 7.62 (3.63)

11.54/0.96 0.13* 8.40 (3.98)

0.34*

8.86/2.72

6.56/3.50

0.48* 2.35 (2.55)

10.34/4.14

6.52/3.55

0.24* 10.97 (6.74)

8.53/3.50

M (SD)

0.29* 2.61 (1.96) -0.02

0.34* 4.62 (3.85)

3.77 (2.78)

Early initiators (N = 104)

a

M (SD)

6.89/3.49

6.21/2.76

5.24/2.49

M (SD)

-0.21* 3.73 (2.74)

7.59/3.45

2.93 (2.20)

Borderline/clinical (%) 6.08/4.47

0.01

3.10 (3.01)

2.65 (2.12)

Rule-breaking behavior 3.13 (3.07)

0.01

6.21/2.07 0.01

Non-early initiators

(N = 4,817) (N = 457) a

M (SD)

10.97/4.24

3.76 (3.20)

None

(N = 145) a

M (SD)

2.63 (3.80)

Early initiators

0.29* 8.97 (6.02)

6.21/3.45

8.30/4.61

3.42 (2.78) 5.47/2.63 10.69 (5.99) 7.00/3.50

7.69/2.88 0.42* 4.23 (3.47)

0.74*

6.73/5.77 0.28* 11.54 (6.22) 0.43* 7.69/1.92

Effect size was obtained using the sexually inexperienced as the reference group

* p B .016, statistically significant after Bonferroni correction

and guide the efforts to developing preventive and intervention programs specific to adolescents’ distinct needs. The percentage of adolescents reporting to have sexual experience in this study was relatively low (5.8–5.3 % for the 10th graders and 11.4–9.1 % for the 12th graders) compared with that in Western societies, e.g., 42.8 % for the 10th graders and 63.1 % for the 12th graders in a 2005 U.S. national survey (Balaji et al., 2008), and 24.2–28.5 % for 15–16 years old and 45.1–49.4 % for 17 years and older in a 2003 survey in Bristish Columbia (Saewyc et al., 2008). This might be partially explained by underreporting due to perceived stigmatization or negative social attitudes. Although sexual initiation in adolescence is less common in Taiwan, our results indicate that these sexually experienced adolescents were associated with a cluster of adverse sociobehavioral consequences, similar to those found in Western societies (Jackson, Sweeting, & Haw, 2012; Schofield et al., 2008), and exhibited a higher level of emotional or behavioral problems that deserve more attention to their health needs. Regarding the concern over early sexual initiation in adolescence, our results indicated that adolescents with sexual initiation before age 16 exhibited a riskier sociobehavioral profile, such as more sexual partners, truancy, coming from a single-parent family, and involvement with a variety of substance use, than those with sexual initiation after age 16.

This may be accounted for in part that younger people have immature cognitive development because their regions of the prefrontal cortex related to impulse control and decision making have not yet matured (Crone & Dahl, 2012; Goldenberg et al., 2013). As the prevalence of female adolescents with early sexual initiation seems to be on the rise in the younger cohort, it warrants further investigation on whether this reflects some secular change in cultural norms. Our use of a comprehensive instrument in assessing adolescent behavior plus the GEE/GLM multivariate analysis helped elucidate the complex, heterogeneous nature of the relationship between early sexual initiation and emotional/ behavioral problems. For example, the lack of association of Withdrawn or Social Problems with adolescent sexual initiation in the crude analysis turned out to be negatively associated with such sexual initiation in the GEE/GLM analysis. This reveals that there are dual directions in the association among components of the internalizing problems. Pooling them together may contribute to previous contradictory results on whether internalizing behavior is associated with adolescent sexual initiation. The associations between adolescent sexual initiation and the externalizing problems were found to be the most salient in this study. These findings were consistent with a previous cross-sectional study (Kapi et al., 2007) and compatible with

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Arch Sex Behav Table 4 Mean syndrome scores of the Youth Self-Report for the sexually experienced adolescents (N = 1,634), by the type of sexual partnership Syndrome

Opposite-sex peers

Male (N = 811)

Same-sex peers

M (SD)

M (SD)

Both-sex peers a

ES

M (SD)

ESa

n = 732

n = 58

Withdrawn

3.88 (3.25)

5.21 (4.79)

0.41*

5.96 (3.21)

0.64*

Somatic complaints

2.51 (3.59)

3.00 (3.25)

0.14

5.56 (3.21)

0.85*

Anxious/depressed

7.22 (6.38)

11.65 (8.21)

0.69*

11.06 (5.49)

0.60*

Social problems

3.38 (2.93)

4.31 (3.44)

0.32*

6.64 (3.77)

1.11*

Thought problems

2.90 (2.21)

3.95 (3.24)

0.47*

5.67 (2.24)

1.25*

Attention problems Rule-breaking behavior

6.82 (3.79) 4.22 (3.35)

7.44 (4.07) 4.20 (4.52)

0.16 -0.01

8.95 (2.88) 7.80 (4.46)

0.56* 1.07*

Aggressive behavior

10.59 (6.91)

12.07 (5.92)

0.21

16.11 (6.60)

0.80*

n = 711

n = 80

Withdrawn

4.03 (2.77)

5.10 (3.39)

0.39*

4.72 (2.84)

Somatic complaints

4.40 (3.79)

5.32 (3.79)

0.24*

4.67 (2.36)

0.07

Anxious/depressed

9.46 (6.00)

11.49 (6.19)

0.34*

10.84 (4.64)

0.23

Female (N = 823)

n = 21

n = 32 0.25

Social problems

3.71 (2.78)

4.20 (2.80)

0.18

4.74 (2.17)

0.37

Thought problems

2.97 (2.11)

3.42 (2.50)

0.21

3.59 (2.19)

0.29

Attention problems

7.64 (3.55)

8.87 (4.06)

0.35*

8.41 (3.57)

0.22

Rule-breaking behavior

3.72 (2.90)

4.30 (2.71)

0.20

4.79 (3.37)

0.37

Aggressive behavior

10.84 (6.06)

12.24 (6.33)

0.23

13.30 (5.20)

0.41*

a

Effect size was obtained using the opposite-sex peers as the reference group * p B .016, statistically significant after Bonferroni correction

Table 5 The association linking sexual initiation with emotional/behavioral syndromes by the Youth Self-Report using GLM/GEE analysis, by grade and gender Variables

10th grade (N = 527)

Male

Female

Non-early initiators Betaa,b (95 % CI)

Early initiators Betaa,b (95 %

Non-early initiators Betaa,b (95 %

Early initiators Betaa,b (95 %

n = 113

n = 152

n = 112

n = 150

Withdrawn

-0.54 (-1.10, 0.03)

-0.68 (-1.19, -0.17)**

-0.61 (-1.13, -0.10)*

-0.83 (-1.35, -0.33)**

Somatic complaints

0.00 (-0.68, 0.70)

0.09 (-0.55, 0.73)

0.00 (-0.65, 0.65)

0.78 (0.08, 1.47)*

Anxious/depressed

0.24 (-0.84, 1.32)

0.02 (-0.90, 0.94)

0.83 (-0.23, 1.89)

0.73 (-0.27, 1.73)

Social problems

-0.88 (-1.36, -0.40)***

-0.53 (-1.06, -0.01)*

-0.45 (-0.95, 0.04)

-0.71 (-1.21, -0.22)**

Attention problems

-0.60 (-1.31, 0.10)

-0.24 (-0.86,0.37)

-0.04 (-0.72, 0.65)

-0.01 (-0.62, 0.59)

Rule-breaking behavior

0.26 (-0.34, 0.87)

1.16 (0.58, 1.75)***

1.10 (0.67, 1.52)***

1.32 (0.82, 1.84)***

Aggressive behavior

1.10 (-0.21, 2.42)

2.68 (1.48, 3.90)***

1.79 (0.71, 2.88)**

2.10 (1.05, 3.15)***

12th grade (N = 1,107)

n = 401

n = 145

n = 457

n = 104

Withdrawn

-0.30 (-0.65,0.04)

-0.74 (-1.46, -0.02)*

-0.38 (-0.68, -0.09)**

-0.39 (-0.91, 0.11)

Somatic complaints

-0.01 (-0.41, 0.38)

-0.36 (-0.90, 0.18)

0.35 (0.00, 0.71)

0.56 (-0.19, 1.31)

Anxious/depressed

0.58 (-0.14, 1.29)

-0.29 (-1.56, 0.97)

0.58 (-0.01, 1.16)

1.89 (0.68, 3.10)**

Social problems

-0.24 (-0.59, 0.10)

-1.01 (-1.53, 0.49)***

-0.32 (-0.60, -0.04)*

-0.55 (-1.11, 0.00)

Attention problems Rule-breaking behavior

0.02 (-0.38, 0.42) 0.76 (0.42, 1.11)***

-0.45 (-1.09, 0.18) 1.12 (0.45, 1.78)***

0.13 (-0.22, 0.47) 0.70 (0.45, 0.96)***

0.70 (-0.06, 1.47) 1.31 (0.65, 1.97)***

Aggressive behavior

1.32 (0.62, 2.02)***

1.55 (0.43, 2.67)**

1.36 (0.79, 1.93)***

2.00 (0.76, 3.23)**

a

Thought problems as the reference behavioral syndromes, and sexually inexperienced same-grade peers as the reference group

b

With adjustment for age, year of survey, area of survey, having a job, weekly allowance, family structure, truancy, and any substance use

* p\.05, ** p\.01, *** p\.001

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Arch Sex Behav

several longitudinal studies, in which either early sexual initiation led to subsequent delinquent behavior (Armour & Haynie, 2007) or delinquent behaviors or externalizing behaviors led to increased risk of early sexual initiation (Caminis et al., 2007; McLeod & Knight, 2010; Price & Hyde, 2009; Udell et al., 2010). What the present study adds is that the association of adolescent sexual initiation with the externalizing problems varied along several facets, i.e., it increased in magnitude with earlier sexual initiation and female gender. Another interesting finding revealed by the GEE/GLM analysis was that the magnitude of the association of Aggressive Behavior was greater than that of Rule-breaking Behavior, opposite to what crude analyses indicated. Although both Aggressive Behavior and Rule-breaking Behavior are classified as externalizing problems, a previous twin analysis of Taiwanese adolescents indicated that their underlying factors are quite different between genders. The majority of the variations of Rule-breaking Behavior for both males and females and Aggressive Behavior for males are attributed to shared environmental factors whereas the main source of the variations for female Aggressive Behavior was due to genetic factors (Kuo, Lin, Yang, Soong, & Chen, 2004). The gender differences in the relationship between sexual initiation and Somatic Complaints and Anxious/Depressed were similar to previous studies (Kuzman et al., 2007; Madkour et al., 2010; Martin et al., 2005; Spriggs & Halpern, 2008). The excess risk of Anxious/Depressed and Somatic Complaints among female adolescents with sexual initiation might be the result of physical impact such as unintended pregnancy (Logsdon, 2004), and the emotional stress associated with an intimate relationship. Although this study did not collect information about adolescent pregnancy, government statistics showed that the birth rate in the past two decades among Taiwanese females aged 15–19 years were 14–18 per 1,000 births, the highest among developed countries in Asia (Lee et al., 2007). Research has indicated that females generally focus much of their attention on relationships and are subject to more emotional challenge regarding issues over unrequited romance and sex during early teens (Crouter & Booth, 2006). The results might be partly due to cultural norms that guide the attitude toward adolescent sexuality. With a higher level of permissiveness with regard to male’s premarital sexualities than to female’s sexualities persisting in Taiwan (Chiao & Yi, 2011), the majority of adults frowned on girls engaging in sexual behaviors and expected teenage girls withhold from initiating sexual behaviors. As a result of higher degree of social condemnation and negative environmental feedback than boys, sexually experienced girls would be subject to more stress and worrisome thoughts. Furthermore, adolescents might transfer the emotional distress into somatic symptoms in order to draw attention from parents (Silber & Pao, 2003). In contrast to the increase in externalizing problems among the sexually experienced adolescents, their scores on the syn-

drome of Withdrawn (characterized by shy and lower degree of independence) and Social Problems (characterized by social isolation and peer rejection and conflict) decreased, regardless of gender and timing of sexual initiation. While the literature on the association between early sexual initiation and Withdrawn and Social Problems is patchy, a study in Chile also found that adolescent sexual initiation was associated with less symptoms in Withdrawn or Social Problems (Sanchez, Grogan-Kaylor, Castillo, Caballero, & Delva, 2010). These findings were in line with previous research showing that adolescents with withdrawn behavior were predisposed to delay their initiation of sexual experience (Tubman, Windle, & Windle, 1996), since they had lower social competence and relatively poor quality in relationships (Rubin, Coplan, & Bowker, 2009). One notable finding was that non-heterosexual partnership was an important correlate of increased scores in YSR syndromes reported by adolescents. For adolescents with samesex partners, regardless of males or females, they had consistently increased scores in internalizing problems such as Withdrawn and Anxious/Depressed. But bisexual adolescents appeared to be quite different between males and females in their associations with YSR syndromes, with male bisexuals having increases in all YSR syndromes but female bisexuals having no increase in YSR syndromes except Aggressive Behavior. One meta-analysis has shown a consistent association between homosexuality or bisexuality and increased risk of a variety of mental disorders, especially depression and anxiety (King et al., 2008). A likely explanation is societal prejudice or stigma against homosexual or bisexual individuals. Although the meta-analysis did not find any gender difference in the association of homosexuality or bisexuality with mental disorder, a study among college students did find that males with gender dysphoria had greater odds ratio with severity sum- score in generalized anxiety disorder, major depressive episode, and dysthymic disorder than their female counterparts (Lai et al., 2010). Whether gender nonconformity played some role in the association, as recent research indicated (Rieger & Savin-Williams, 2012), or explain the pervasiveness in the increase of YSR syndromes for male bisexuality cannot be evaluated in this study since we did not collect information in this aspect. Our GLM/GEE analysis did not adjust for non-heterosexual partnership since the number of these adolescents was too small. Our results should be interpreted with some limitations in mind. First, the cross-sectional nature of this study precludes making causal inferences concerning the impact of early sexuality. Since the YSR asks about information in the past 6 months, we tentatively put YSR syndromes as outcome variables. However, we cannot exclude the possibility that these emotional or behavioral problems had been pre-existing before the sexual initiation. Second, the measurement of sexual history did not specify whether the sexual behaviors

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were voluntary or forced. Third, given the present data were based on a self-report questionnaire, there is potential information bias regarding the validity of the contexts wherein sexual history and the emotional problems occurred. Nevertheless, if the reporting error is non-differential, it might lead to an underestimation of the risks linking sociobehavioral traits and emotional and behavioral problems to early sexual initiation. Lastly, since our analyses were limited to high school-attending students, our results may not be generalizable to dropouts (around 5 % among high school students in Taipei in the past decade) or other school-attending populations. In summary, this study investigated the relations of adolescent sexual experiences to a spectrum of emotional/behavioral problems using multivariate response profile regression in a nationally representative sample of high school students in Taiwan. Our results revealed that adolescents with sexual initiation may differentially experience higher levels of a variety of emotional and behavioral problems. Externalizing problems were associated with earlier sexual initiation whereas increased risk of internalizing problems was predominately significant in females. The knowledge of these associations of the emotional or behavioral problems with early sexual initiation should be incorporated in sex education that is to improve the health and well-being of adolescents. Acknowledgments This work was supported by grants from the Department of Health, Taiwan (DOH93-NNB-1012, DOH94-NNB1014, DOH95-NNB-1012, DOH96-NNB-1041, and DOH97-NNB-1018); the DOH had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication. The authors thank Drs. Chuhsing Kate Hsiao, Chih-Yin Lew-Ting, Ching-Mei Lee, Cheng-Fang Yen, DuanRung Chen, Chaucer C.H. Lin, Ming-Jen Yang, and Te-Jen Lai for their help in the design and conduction of the National Survey of Illegal Drug Use among Adolescents.

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