Complex sentence: Most studies of ACT so far have been conducted on adults and therefore the knowledge of its effectiveness when applied to children and adolescents is limited, but studies done on ACT in relation to children, adolescents and their parents, have shown positive outcomes.
Split into simpler sentences: Most studies of ACT so far have been conducted on adults and therefore the knowledge of its effectiveness when applied to children and adolescents is limited. But studies done on ACT in relation to children, adolescents and their parents, have shown positive outcomes.