Objectives: ：Adolescents cigarette smoking is a major public health concern, because it is highly associated with physical and mental development of adolescents. This study examines the psychosocial variables affecting smoking behaviors and smoking cessation plan. Methods: ：A total of 74 (35 smokers and 40 non-smokers) students in Daegu metropolitan city were included in this study. 35 smokers visited smoking cessation center between September 2019 and November 2019. Subjects were asked to complete a self-reported questionnaire evaluating smoking status, self-esteem, parent-adolescent communication, parent and peer attachment, and peer relationship quality. The independent t-test was conducted to determine the difference in psychological variables between smoker and non-smoker. Additionally, logistic regression analysis was done to identify the factors that affect smoking cessation plan and willingness. Results: ：The majority of adolescent smoker was male (94.3%) and middle school students (82.9%). Twenty-four smokers (68.5%) started smoking at sixth and seventh grade. The smoking amount and smoking days were related to plan and willingness of smoking cessation in logistic regression analysis and the number of friends who smoke was related to smoking cessation plan. The openness of communication in smoking students was significantly higher than that of non-smoking students. Conclusion ：Our findings indicate that the environmental factors such as peer or parental smoking is important in adolescents smoking. In addition to individual factors such as smoking amount and days, openness of communication related with impulsivity and susceptibility in peer pressure can affect plan or willingness of smoking cessation.

Objective: The primary objective of this study was to investigate the effect of methylphenidate (MPH) on height, weight, and body mass index (BMI) in drug-naive children and adolescents with attention deficit hyperactivity disorder (ADHD) over 24 months. The secondary objective was to investigate whether the age of MPH initiation and sex act as risk factors for growth retardation. Methods: A total of 82 patients with ADHD were included. Weight, height, and BMI were measured at baseline and every 6 months up to 24 months. Weight, height, and BMI data were converted to z-scores and analyzed using two-way repeated-measures ANOVA and multiple linear regression. Results: The z-score of height, weight and BMI decreased from the baseline values. The z-scores of height were at baseline 0.002; 6 months -0.100; 12 months -0.159; 18 months -0.159; 24 months -0.186. The z-scores of weight were at baseline 0.104; 6 months -0.155; 12 months -0.256; 18 months -0.278; 24 months -0.301. Here were no age and sex differences of height, weight, and BMI. Conclusion The use of MPH was associated with attenuation of weight and height gain rates in children and adolescents with ADHD.