First of all, most students, even psychologically healthy students, do have different (or even sometimes opposite) behaviours at home and at school. Having said that, we do need to understand the reason(s) behind such differences of your child. Sometimes, the differences may be only a kind of adaptation process that the difference may be diminished after you child has successfully adapted to a new environment. Even if your child has already adapted to a new environment and still behaves differently between at home and at school, that kind of different behaviour may sometime be necessary to maintain a desirable balance between the school and the home, for example, the school requires a very strict or proper behaviour for students, e.g., stay very quiet in classes, does not raise ‘unnecessary questions’ in classes, etc. Hence, your child may be just trying to maintain those proper behaviour required by school, and only shows his own personality to be talkative and lively at home. Of course, if your child’s different behaviours are due to other factors that needs to be attended by parents or teachers (e.g., being bullied by people at school), you need to seek help from a qualified mental health professional then.