Preschool is the period during which children develop social skills by engaging in relationships with friends and peers outside of the family, and obtaining the behavior, knowledge, and techniques required to live amongst others. Preschool is also the period in which adaptation to social environments and social and psychological difficulties become prominent [1]. Problem behaviors can occur when children do not adapt appropriately to social life, and can be divided into internalizing and externalizing problem behaviors. Internalizing problem behaviors include overly–restrained behaviors such as social withdrawal and somatic symptoms, such as physical complaints, anxiety, and depression. Externalizing problem behaviors include actions toward others that exhibit a lack of control and are inappropriate, such as aggression and misconduct [2].

Problem behaviors in children extend from their childhood into their adolescence and adulthood [3]. However, preschool children's problem behaviors are often not taken seriously or not appropriately treated, because the expression and symptoms of the behavior are not as prominently displayed as in adolescents [4]. If such behaviors are not adequately addressed, children may develop more serious problems such as running away from home, drug abuse, excessive drinking, suicide, and school violence, which may lead to crimes throughout their adolescence and adulthood [5]. This can be detrimental to society, with direct costs for individuals and social welfare. If problem behaviors that develop in preschool are not treated until adolescence, tremendous time and effort are required to solve the problems that have been internally developed and habituated from an early age, and treatment is rarely effective [6]. A longitudinal study of preschool children in South Korea reported that those who displayed serious problem behaviors continued to do so in follow-up studies [7]. Another longitudinal study conducted in the Netherlands reported that children who displayed relatively serious problem behaviors in childhood were 4.6 times more likely to develop mental illnesses than other children [8]. Identifying children's problem behaviors at an early stage is thus important to effectively prevent and reduce the development of chronic behavior.

Children's problem behaviors are also socially significant and closely related to parenting attitudes [9, 10]. Abidin [6] mentioned that the greatest influence on children's problem behaviors are parenting attitudes, which is influenced by parental stress, the degree of parenting alliance perceived by the parents, and coping methods for managing parenting stress. Parenting stress signifies the psychological burden or pressure that parents experience when raising children: when they experience high stress, positive parenting attitudes tend to decrease and negative ones increase [6, 9]. Excessive parenting stress makes parents doubt their roles, which can have a negative influence on children's psychological and emotional states. The children may then exhibit similarly withdrawn or excessive behavior to that of the parents, which can eventually cause the children's problem behavior [11]. In particular, parenting stress and parenting attitudes are influenced by the interaction of both parents [12]; therefore, parenting stress and parenting attitudes need to be analyzed separately from the data of the mother and father.

Overly strict and authoritarian parenting attitudes can cause problem behaviors in children, such as resistance to parents, leading to a vicious cycle in the child-parent relationship that may cause antisocial externalizing behaviors such as physical violence [13]. A study of Belgian children found that parental rejection and controlling attitudes were closely related to children's internalizing problem behaviors, such as depression, and externalizing problem behaviors, such as misconduct and aggression [14]. In a study of mothers from Arabic countries, the children of mothers with controlling parenting attitudes were found to be more likely to display increased levels of internalizing and externalizing behaviors [15]. Parenting attitudes that involve verbal abuse and criticism of children may result in the child feeling rejected, so it is likely that controlling parenting attitudes strongly influence children's problem behaviors. Hostility and irrational parenting attitudes can also hinder children's positive development because they form negative representations of their parents, which not only increase their externalizing problem behaviors but also have long-term negative effects [16].

Children's problem behaviors cannot be measured by identifying parenting stress and parenting attitudes at specific points, but must be approached based on changes over time. However, most previous research on children's problem behaviors, and on parenting stress and parenting attitudes, has measured the concept at specific points in time [1]. Studies using cross-sectional data sets have found that it is difficult to comprehend how parenting stress and attitudes change over time and with changes in the children's age. Most cross-sectional research has emphasized the importance of studying aspects of behavior and individual differences that change over time [10, 17, 18]. As the parent-child relationship lasts for a lifetime and the qualities of such relationships have strong long-term and progressive influences [19], it is particularly important to observe the effects of parenting stress and controlling parenting attitudes on the problem behaviors of children over the long-term.

From this perspective, the latent growth model estimates the change trajectory of an individual at a certain point of time based on repeated measurement data, and the individual initial estimates of the changes are collected to calculate the average initial value, the rate of change, and the individual difference. The model can also verify the relationships among changes in several variables of interest. Associating the starting point (initial value) of the variable of interest and the rate of change (slope) is extremely useful. The latent growth model improves on cross-sectional models that verify the indirect effects of parameters in the relationship between independent variables and dependent variables, as it explains how independent variables are related to the changes in the parameters and the dependent variables [20]. The effect of parenting stress and controlled parenting attitudes on children's problem behaviors should be examined from a long-term viewpoint. Confirming the relationships among variables using the latent growth model is thus more meaningful.

Therefore, this study aims to identify how parenting stress and controlling parenting attitudes influence the problem behaviors of preschool children. The latent growth model allows the changing influences over time to be identified and provides preliminary data for the development of parent and children programs that can help prevent problem behaviors in children.

In this study, the longitudinal growth trajectories of the problem behaviors of children were analyzed, along with the parenting stress and attitudes of parents of preschool children, using data from the fifth to seventh panels of the study of Korean children. The research results and the related managerial implications are as follows.

First, examination of the growth trajectories of each factor in this study revealed that parenting stress differed between individuals and decreased over time. These results are similar to those of a study of American mothers [17], in which a group of mothers with chronic parenting stress exhibited individual differences in stress. Another study [18] of American preschool children reported that parenting stress decreased as children became older. This suggests that parents tend to assess the difficulty of child-rearing as higher in the postnatal and early childhood period, when activity gradually increases, and parents are still acquiring their parenting methods. However, as children transition from the postnatal and early childhood period to the preschool period, parenting stress gradually decreases because the level of communication and role sense increase between parents and children. However, as parenting stress shows individual differences and progresses rapidly with time, particularly for parents with low intercepts of parenting stress, the regulation of early stress and individual approaches are considered significant. Controlling parenting attitudes differ between individuals and generally decrease over time, and the results of this research are similar to those of a previous study [26] of parenting attitudes. Although numerous factors can cause changes in parenting attitudes, parental stress is recognized as a significant influence, which suggests that individual differences occur due to decreases in parenting stress in relation to parenting attitudes. However, similar to parenting stress, controlling parenting attitudes exhibited individual differences. The slope progressed rapidly over time for parents with low intercepts of controlling parenting attitudes, and it is thus important to adopt an individual approach to parenting stress and attitudes after understanding the precise individual intercept values.

Children's problem behaviors indicated individual differences and tended to decrease with time. Similar results were found in a study conducted for Korean preschool children between the ages of three and five. The children's problem behaviors indicated individual differences [27], and problem behavior decreased with age [18]. Such results are assumed to be due to the parents assessing that children's problem behaviors decrease as they develop emotional control and delayed gratification with age, as does negotiation with adults, and their needs are expressed verbally as linguistic competence develops. However, this study demonstrates that accurately understanding the individual intercept values of children before developing interventions is necessary, because the slopes of internalizing and externalizing problem behaviors rapidly increased with time for children who initially had low degrees of internalizing and externalizing problem behaviors at the intercepts. Early interventions using appropriate diagnoses are necessary for children at risk of emotional problem behaviors, because if the behavior begins in the preschool period, it can severely worsen and manifest in different forms over time, increasing the children's probability of risking social maladjustment [3, 8].

Second, by analyzing the multivariate latent growth model of parenting stress, controlling parenting attitudes, and children's problem behavior, parents' intercepts in parenting stress also affected their intercepts in controlling parenting attitudes, and the slope of the fathers' parenting stress was the only factor affecting the slopes of the mothers' controlling parenting attitudes. These results are similar to those of a cross-sectional study of Korean mothers with infants, in which positive parenting attitudes were found to rapidly decrease with rapid increase in parenting stress [28]. Such results become factors in determining parenting stress and attitudes perceived by the parents, as parenting stress causes parents to be doubtful about their roles, and they exhibit increased tendencies of excessive behavior toward their children to resolve the situations facing them [10]. In this study, it was found that mothers' controlling attitudes were affected more by the fathers' parenting stress than by changes in their own parenting stress. This is similar to a cross-sectional study of Korean parents in which the fathers' parenting participation, values about children, and parenting knowledge influenced the mothers' parenting stress [29]. Research has shown that parenting stress affects the determinants of parenting attitudes, such as couples' parenting cooperation and stress-coping methods and how such factors rebound to affect parenting attitudes [6]. Therefore, it can be assumed that these results are due to the fathers' parenting stress affecting the determinants of the mothers' parenting attitudes. Therefore, although regulation of parents' individual intercepts is important in controlling parenting stress, regulating parenting stress with long-term rather than short-term plans by viewing parents as one entity, as opposed to individual units, can be an effective method of decreasing controlling parenting attitudes.

The internalizing and externalizing problem behaviors of children were also found to be significantly influenced by the intercept and slope values of parenting stress and controlling parenting attitudes. These results are similar to those of a study with American preschool children, in which children displayed more problems related to peers and emotions as their mothers had higher parenting stress [1], and to research with Korean adolescents, in which externalizing problem behavior was found to increase with an increase in the mothers' controlling parenting attitudes [30]. Another study found that excessive parenting stress affected parents' psychological and emotional states, such as depression, and these states led to inappropriate interactions between the parents and children [11]. This can be the case particularly for preschool children, for whom interaction with parents is important, as they are negatively affected in terms of adjustment and development by a parent's unstable psychological and emotional states. In addition, overly strict and authoritarian parenting parenting attitudes can cause problem behaviors in children such as resistance, and such resistance leads to vicious cycles in their relationships with their parents, which can manifest as antisocial externalizing problem behaviors such as violence [13]. Therefore, appropriate education and intervention programs should be applied by taking parents as one unit, in addition to considering the children, to decrease their problem behaviors. Long-term approaches and interventions for parents and children are necessary, because the problem behaviors of children change according to changes in parenting stress and controlling parenting attitudes.

As the intercepts and slopes of the fathers' parenting stress were found to influence the problem behaviors of children as mediators of controlling parenting attitudes, activities and organized approaches related to fathers' parenting stress and slopes can help in addressing children's problem behaviors.

Suggestions for future research are as follows. First, thorough analyses are necessary regarding the direct and indirect effects of various variables that influence parenting stress and attitudes on parenting attitudes. Second, because the changes were verified over a period of three years, using the 5^th~7^th panels on Korean children, future in-depth research is suggested for analyses that more comprehensively examine the correlations and causalities of how parenting stress changes and parenting attitudes are affected according to the children's preschool and postnatal periods by exploring documents from more perspectives, since parenting stress and attitudes are predicted to be different between preschool and postnatal periods.

This study longitudinally interpreted the effects of parenting stress and controlling parenting behavior on the problem behaviors of preschool children using a latent growth model. This study's significance is that it longitudinally confirms the growth trajectories of parenting stress, controlling parenting attitudes, and problem behaviors of children using national data. To analyze parenting stress and parenting attitudes, changing aspects must be examined from a longitudinal perspective, rather than by interpreting the values at certain points in time. Therefore, it is important to precisely measure the changing aspects of parenting stress and parenting attitudes during the process of children becoming healthy adults and members of society, and it is necessary to establish community facilities and allocate professionals who can regularly check parents' emotional states after children's birth. Parenting stress is expected to decrease along with improvements in parenting attitudes if intervention programs are applied to help reduce the stress.