[Gender and age-specific aspects of mental health in children and adolescents].

Boys had lower levels of prosocial behavior and higher levels of all mental health problems except emotional symptoms compared to girls.

• Assessment was conducted using the parent-report Strengths and Difficulties Questionnaire (SDQ) in a population sample of 9,648 children and adolescents (50% female).
• Gender differences accounted for less than 1% of the variation across all measures, except for internalization (2.4%) and hyperactivity/inattention (3.1%).
• Emotional symptoms were the one domain where boys did not show higher problem levels than girls.

Age contributed substantially more than gender to variation in mental health indicators across the sample.

• Age accounted for 6.2% of the variation in hyperactivity/inattention.
• Age accounted for 3.6% of the variation in internalization.
• Age accounted for approximately 3% of the variation in emotional symptoms, externalization, and the impact of mental health problems on children's daily lives.
• Multivariate analysis of variance was used to assess effects of gender, age, and their interaction, with subsequent comparisons using the Tukey method.

In adolescence, the level of mental health problems and their impact on daily life decreased significantly, with these changes more pronounced in boys.

• The decline in mental health problems during adolescence was observed across the sample of children aged 2–18 years.
• Changes were more pronounced in boys than in girls.
• The impact of mental health problems on children's daily lives also decreased in adolescence.

Age-related characteristics of prosocial behavior and peer relationship problems did not differ by gender, while age trends for other mental health indicators differed between boys and girls.

• The age characteristics of prosocial behavior and peer relationship problems were not associated with gender among children.
• Age trends for other indicators (e.g., hyperactivity/inattention, emotional symptoms, externalization) differed between boys and girls.
• This gender-by-age interaction was assessed using multivariate analysis of variance.

The study sample comprised 9,648 children and adolescents from Siberian regions, spanning four age groups from preschool through late adolescence.

• The sample included 50% female participants.
• Age groups: 2,316 preschoolers aged 2–6 years (24%), 3,449 junior schoolchildren aged 7–10 years (36%), 1,839 junior teenagers aged 11–14 years (19%), and 2,044 older teenagers aged 15–18 years (21%).
• Eleven percent of participants lived in rural areas.
• Mental health was assessed using the parent-report SDQ, with the Russian version previously validated by the authors.