This study aimed to identify the directionality of the causal relationship and interaction between depression and amount of smoking over time in hardcore smokers using longitudinal descriptive analysis.

Secondary data from the Korean Welfare Panel Study were analyzed using autoregressive cross-lagged modeling. Participants included 342 hardcore smokers who participated in the 8th to 11th waves of the panel study.

Analyses revealed that change(s) in depression levels according to time had a significant positive relationship with the total amount of smoking per day (β=.29, β=.19, β=.17, p<.001), while change(s) in total amount of smoking per day according to time had a significant positive relationship with depression (β=.43, β=.50, β=.38, p<.001). Analysis of the cross-lagged effect between depression and total amount of smoking per day showed that depression at one time point had a significantly positive relationship with the total amount of smoking per day at the next time point (β=.14, β=.13, β=.13, p=.021), and that the total amount of smoking per day at one time point had a significant positive relationship with depression at the next time point (β=.04, β=.04, β=.03, p=.044).

The findings in the present study confirmed a cross-interaction between depression and total amount of smoking per day in hardcore smokers. The present findings could be used to develop appropriate smoking-related interventions.

This study was conducted to examine the longitudinal effects of parenting stress and parental control attitudes on problem behaviors in preschool children, using a latent growth model.

Participants were 1,724 pairs of parents and 1,724 preschool children who had completed the panel survey on Korean children (5^th~7^th survey panels).

An analysis of the multivariate latent growth model of parenting stress, parental control attitudes, and children's problem behaviors suggested that the parents’ intercepts for parenting stress influenced their intercepts for parental control attitudes (father: b=.21, p<.001; mother: b=.55, p<.001). In addition, the slopes for fathers’ parenting stress was the only aspect that affected the slopes for mothers’ parental control attitudes (b=.77, p<.001). Moreover, both the intercepts and slopes of parenting stress and parental control attitudes significantly affected the children's problem behaviors.

This study is significant as it provides longitudinal evidence of the impact of parenting stress and parental control attitudes on children's problem behaviors. The findings suggest that accurately assessing changes in parenting stress and parental control attitudes and developing intervention programs to reduce them will be effective in reducing problem behaviors in children.

The purpose of this study was to develop a system dynamics model for adolescent obesity in Korea that could be used for obesity policy analysis.

On the basis of the casual loop diagram, a model was developed by converting to stock and flow diagram. The Vensim DSS 5.0 program was used in the model development. We simulated method of moments to the calibration of this model with data from The Korea Youth Risk Behavior Web-based Survey 2005 to 2013. We ran the scenario simulation.

This model can be used to understand the current adolescent obesity rate, predict the future obesity rate, and be utilized as a tool for controlling the risk factors. The results of the model simulation match well with the data. It was identified that a proper model, able to predict obesity probability, was established.

These results of stock and flow diagram modeling in adolescent obesity can be helpful in development of obesity by policy planners and other stakeholders to better anticipate the multiple effects of interventions in both the short and the long term. In the future we suggest the development of an expanded model based on this adolescent obesity model.