Malnutrition in children and adolescents is a global issue, particularly in low- and middle-income countries, while behavioral problems are becoming a growing public health concern in the area of child and adolescent mental health, with very few studies examining their association in preadolescence. This study aimed to assess the epidemiological relationship between malnutrition and behavioral problems in preadolescence. A school-based, cross-sectional survey was conducted in Pakistan. A total of 660, 11-12-year-old preadolescents were selected from a middle-class, co-educational school chain. Socio-demographic questionnaires and an officially adapted version of the Youth Self Report Form (YSR), which is the child and adolescent reported version of the Child Behavior Checklist (CBCL), were used to collect data, along with anthropometric assessments following the WHO protocol. Thin and stunted preadolescents had significantly higher odds of internalizing problems (AOR= 2.05, P= 0.003 and AOR= 2.09, P= 0.039, respectively) than normal ones. Over-nutrition was not associated with any behavioral issues. According to the composite index of anthropometric failure, 40% of preadolescents had at least one type of malnutrition, and among them, about 3% had co-occurring malnutrition (stunted and thin or overweight). They had a higher risk of being associated with internalizing problems (AOR 2.92, P = 0.027). The effect was considerably higher than that associated with stunted or thin only, highlighting the cumulative impact of the co-occurring malnutrition on the internalizing problems. Our study concludes that over- and under-nutrition are prevalent in preadolescents, with a significant association of under-nutrition with internalizing problems. Moreover, our study is the first that report that the co-occurrence of malnutrition is significantly associated with increased risk of internalizing problems. This study highlights the importance of the link between physical and mental health and emphasizes the need for holistic interventions and programs for addressing preadolescents' issues.

Data were collected by trained enumerators using standard instruments on paper-based forms under the supervision of the principal investigator. Data were entered into a pre-designed software and later analysed in SPSS software.