Introduction
For decades, the role of parenting behaviors in the development of child psychopathology has been a major focus of research. Early
parent-effect models, which proposed a unidirectional relationship from parenting to child outcomes [
1], evolved to take into account
child-effects, in which child characteristics and behaviors modify parental behaviors [
2]. Thus, the coercive processes model proposes that the parents’ failure to maintain child compliance in their early interactions initiates a continuing cycle of dysfunctional exchanges. More precisely, ineffective parental demands in response to a child’s problem behavior (e.g., aggression or anger outbursts) are followed by the child’s refusal to comply, which, in turn, elicits further ineffective parenting (e.g., withdrawal) [
3,
4]. Consequently, over time, the child’s aggressive behavior increases, and the parents’ capacity to regulate the child’s problematic behavior decreases.
Repetti et al.’s [
5] model places a major emphasis on such neglectful and harsh family environments, which are proposed to result in emotional dysregulation in children, which, in turn, is thought to be implicated in the development of both externalizing and internalizing psychopathology. With respect to the latter, internalizing symptoms in children and adolescents are particularly linked to coping strategies involving disengagements, such as emotion suppression, avoidance, and denial [
6]. Thus, unlike children showing externalizing problems who become ensnared in coercive exchanges with parents, siblings, and peers [
4], those with internalizing symptoms may prevent or disrupt these vicious cycles by withdrawing from the hostile situation.
To date, two meta-analyses have examined the relationships between harsh parenting and child externalizing and internalizing problems, respectively [
7,
8]. In the first, Pinquart examined whether later externalizing symptoms are predicted by harsh parenting at earlier stages of development, after adjusting for initial levels of externalizing symptoms, and vice versa [
7]. Consistent with transactional models of developmental psychopathology, Pinquart found bidirectional effects between harsh parenting and child externalizing symptoms, i.e., harsh parenting led to higher rates of externalizing symptoms in the child, while externalizing problems in the child elicited more harsh parenting over time [
7]. In contrast, in the second meta-analysis of cross-lagged associations between harsh parenting and child internalizing problems, Pinquart [
8] found only a unidirectional effect, whereby harsh parenting predicted internalizing problems, but
not vice versa. In sum, harsh parenting appears to be reciprocally related to child externalizing symptoms, whereas only a unidirectional relationship from harsh parenting to child internalizing symptoms has been observed.
However, it should be noted that the vast majority (96%) of the studies included in the meta-analysis on cross-lagged associations between harsh parenting and child externalizing symptoms were from high-income countries (HICs) [
7] (the relevant information could not be extracted from the meta-analysis on internalizing symptoms [
8]). Just four studies were conducted in low- and middle-income countries (LMICs), and only one of these was population-based [
9]. This lack of evidence from LMICs is also reflected in a third meta-analysis by Pinquart and Kauser [
10], in which country-level differences in cross-lagged associations between harsh parenting and child externalizing and internalizing problems could not be estimated due to the small number of studies from non-Western countries.
This gap in the evidence base is concerning, given that almost 90% of all children and adolescents worldwide live in LMICs [
11]. Importantly, effects of harsh parenting on child externalizing and internalizing problems may depend partly on cultural norms. In particular, it is proposed that the effects may be attenuated in countries in which harsh punishment is more common and widely accepted [
12,
13]. For example, Lansford et al. [
12] found that corporal punishment led to increased levels of child externalizing and internalizing problems across low-, middle-, and high-income countries. However, effect sizes were smaller in countries in which corporal punishment was perceived as more normative [
12]. Although the use of physical and verbal punishment is common worldwide, there is considerable between- and within-country variability [
14], especially for more severe forms of harsh parental discipline [
15]. Consequently, the effects of harsh parenting on child externalizing and internalizing problems may differ across countries, and it remains unclear if the findings obtained in HICs translate to LMICs.
To address these gaps in the literature, we examined the association between harsh, aggressive, or abusive parenting (hereafter referred to as
harsh parenting), defined as physical and psychological aggression towards the child, and child externalizing and internalizing symptoms, in the 2004 Pelotas Birth Cohort study. This is a large population-based sample based in Brazil, a middle-income country with high levels of crime and violence, especially amongst adolescents [
16,
17]. The main objectives of the present study were: (i) to test whether harsh parenting is associated with child conduct and emotional problems in a LMIC context; and (ii) to examine whether there are unidirectional or reciprocal relationships between harsh parenting and child conduct and emotional problems, using autoregressive path models to test for cross-lagged associations. In line with previous research [
7,
8], we hypothesized that harsh parenting would be reciprocally related to child conduct problems, whereas only a unidirectional relationship would be observed between harsh parenting and child emotional problems. Given that examination of sex differences has been limited in previous research—even when considering HICs [
7,
8]—we tested whether the effects of harsh parenting vary according to the sex of the child, and also whether the stability of child externalizing and internalizing symptoms differs by sex.
Discussion
To our knowledge, this is the first study to use a prospective longitudinal design and a population-based sample to examine cross-lagged associations between harsh parenting and child conduct and emotional problems in a low- and middle-income country (LMIC). We found bidirectional effects between harsh parenting and child conduct problems (i.e., harsh parenting at age 6 years predicted conduct problems at age 11, even after adjusting for initial levels of conduct problems, and vice versa), but only a unidirectional relationship between harsh parenting and child emotional problems (i.e., harsh parenting at age 6 years predicted emotional problems at age 11, even after adjusting for baseline emotional problems, but not vice versa). We also examined whether sex moderated the strength or nature of the cross-lagged and autoregressive effects, but found no robust evidence for sex differences in these associations.
Previous studies have indicated that the effects of harsh parenting on child externalizing and internalizing problems may depend partly on cultural norms related to harsh parenting practices [
12], suggesting heterogeneous effects across different cultural contexts. However, our findings from Brazil are in line with two meta-analyses of cross-lagged associations that almost exclusively included studies from HICs, which showed bidirectional effects for externalizing problems and unidirectional effects for internalizing problems [
7,
8]. Effect sizes were small but in line with those reported in previous meta-analyses [
7,
8]. On the basis of small effect sizes for parenting effects, some researchers have argued that there is insufficient evidence to categorically oppose physical punishment [
35]. Others, however, have disputed this idea, stating the lack of evidence in support of physical punishment [
36]. Some researchers have argued for a continuum of violence against children [
37], with spanking and physical abuse both involving expression of harsh parenting and negative child outcomes, just to different degrees [
38]. Thus, it should be noted that harsh parenting in the current study may better be described as harsh, aggressive, and abusive parenting. Nevertheless, there are substantial differences between countries in the prevalence of harsh parenting, and future research across cultural contexts is warranted [
15].
The present findings provide support for transactional models between negative parental discipline and child conduct problems. According to Patterson’s coercive processes model of antisocial behavior [
3,
4], dysfunctional parent–child interactions in early development lead to an incremental decline in the quality of the parent–child relationship. These coercive cycles may continue into middle and late childhood as well as adolescence and extend beyond the family context to affect behavior in school or within the peer group. According to social information processing theory and social learning theory [
39,
40], children may internalize their parents’ harsh and abusive behavior, and, as a consequence, are unable to generate appropriate responses to situations of conflict and distress. Consequently, harsh parenting may play an important role in initiating child conduct problems. However, as Patterson notes, child characteristics, including, for example, difficult temperament, may negatively impact parenting practices [
4].
The findings also provide evidence for a unidirectional parent-effects model of the association between negative parental discipline and child internalizing problems. Serbin et al. [
41] found a negative feedback loop between parenting and child internalizing outcomes measured in the context of a longitudinal design, i.e., child internalizing problems at wave 1 led to an increase in positive parenting behaviors at wave 2, which, in turn, led to a decrease in internalizing problems at wave 3. In contrast, a recent meta-analysis found child internalizing symptoms led to reduced parental warmth and authoritative parenting, and increases in psychologically controlling and permissive parenting behaviors [
8]. This implies that similar vicious cycles to those proposed by Patterson [
3,
4] may apply to child internalizing problems, but with different expressions of ineffective parenting strategies. For example, cold, unsupportive, and neglectful parenting may lead to an increase in child internalizing problems and, similarly, a withdrawn child may evoke less parental engagement and fewer stimulating interactions. However, the current study was not designed to examine whether such effects exist in our sample.
In line with previous research, we found higher levels of conduct problems in boys compared to girls [
42]. Furthermore, boys were exposed to higher levels of harsh parenting than girls, which may have contributed to them developing higher rates of conduct problems, and vice versa. However, despite these sex differences, the reciprocal relationship between harsh parenting and child conduct problems did not differ by sex. In contrast, the association between harsh parenting and child emotional problems was only significant for girls, but not boys. However, when we directly compared boys and girls, there was no significant sex difference in the strength of this effect. Unlike in previous studies, we did not find higher levels of emotional problems in girls compared to boys, which may partly explain the non-significant sex difference [
43]. As studies on sex differences in these relationships have mostly been limited to HICs, with just two small-scale studies testing for sex differences in cross-lagged associations between harsh parenting and child externalizing problems in LMICs [
44,
45], further research on this topic is needed in LMICs.
Key strengths of the current study include the use of a large, birth cohort sample from Brazil, with very high retention rates, and the availability of prospective longitudinal data. Furthermore, the majority of studies testing for cross-lagged associations between parenting dimensions and child externalizing and internalizing problems have been conducted in HICs [
7,
8,
10]. Thus, we were able to examine whether the findings obtained in HICs extend to LMICs, including the direction of effects in the parent–child relationship and sex differences.
However, our study also had a number of limitations which should be considered when interpreting the findings: First, all measures were completed by a single rater, usually the mother, and therefore may have been subject to shared rater bias, which may have inflated associations between variables. Second, parents may under-report child emotional problems [
46], especially in the case of girls [
47]. Thus, future studies should attempt to mitigate against these issues by using both parent- and self-reports of child psychopathology. Third, there was selective attrition over time. These effects, however, were small and addressed through the use of multiple imputation, using an adequate number of imputed data sets, and taking the child’s sex into account [
31,
32]. Furthermore, the findings were similar when listwise deletion was used to deal with missing data rather than multiple imputation. Fourth, the SDQ subscales showed modest internal consistency. Although, the SDQ is a widely used measure, the current results require replication, using a measure of child conduct and emotional problems with better psychometric properties. Fifth, with data available from only two time points, we were not able to examine a sequence of change (i.e., a feedback loop) between harsh parenting and child conduct and emotional problems, respectively, which would require data from a minimum of three time points. Data collection for the age 15-time point is currently underway, which will allow researchers to investigate these issues, in addition to modelling developmental trajectories of child conduct and emotional problems, respectively. Finally, the relationship between harsh parenting and child conduct problems may be in part explained by genetically mediated child-effects, especially in the case of less severe forms of harsh and abusive parenting [
48]. However, the current study was not designed to investigate this possibility.
Given the bidirectional effects between harsh parenting and child conduct problems reported here and in other studies conducted in HICs [
7], future interventions aimed at targeting harsh and abusive parenting to reduce conduct problems should also include child-focused components, directly targeting child behavior problems. In contrast, preventive interventions to address child internalizing problems may primarily focus on parent-focused components. In HICs, there is strong evidence for the effectiveness of parent training programs for child conduct problems, focusing on reducing harsh parenting and promoting positive parenting [
49], with only preliminary evidence available from LMICs [
50]. Upcoming trials will further elucidate the effectiveness of such parenting programs in Brazil [
51].
In conclusion, we found reciprocal relationships between harsh parenting and child conduct problems, and unidirectional effects of harsh parenting on child emotional problems, with no significant sex differences observed in either model. Our findings highlight the detrimental impact of harsh parenting on child psychopathology and demonstrate the importance of targeting both parent- and child-effects in preventive interventions aiming to reduce harsh parenting and promote positive parenting.
Acknowledgements
We are extremely grateful to all families who took part in the 2004 Pelotas birth cohort study, as well as to the whole Pelotas cohort team, including interviewers, data clerks, laboratory technicians, and volunteers. This article uses data from the study entitled “Pelotas Birth Cohort, 2004”, conducted by the Graduate Program in Epidemiology of the Federal University of Pelotas, in collaboration with the Associação Brasileira de Saúde Coletiva (ABRASCO, Brazilian Public Health Association). Previous phases of the study were supported by the World Health Organization (Grant no. 03014HNI); the Brazilian National Programa de Apoio a Núcleos de Excelência (PRONEX, Support Program for Centers of Excellence; Grant no. 04/0882.7); the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazilian National Council for Scientific and Technological Development; Grant nos. 481012-2009-5, 484077-2010-4, 470965-2010-0, 481141-2007-3, 474023/2011-7 and 426024/2016-8); the Brazilian National Ministry of Health (Grant no. 25000.105293/2004-83); and the Children's Pastorate. IS Santos, AJD Barros, FC Barros, and A Matijasevich receive support from CNPq. The mental health component of the 11-year follow-up was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, São Paulo Research Foundation; Grant no. 2014/13864-6). Andreas Bauer is supported by a University Research Studentship Award from the University of Bath. Gemma Hammerton is supported by a Sir Henry Wellcome Postdoctoral Fellowship (209138/Z/17/Z). Joseph Murray is supported by a Wellcome Trust Investigator Award (210735_Z_18_Z).