Systemic therapy seeks to address people both on an individual level as well as people in relationships, dealing with the interactions of groups and their interactional patterns and dynamics. Systemic therapy is effective for children’s and adults’ difficulties, both when individuals have acquired a mental health diagnosis and when there is more general or complex distress. It is effective across the lifecycle, spanning developmental stages from under-fives to old age. Working therapeutically with individuals together with their families and/or significant others enables the use of individuals’ relationships as a resource, and reduces stress and difficulties for all family members. Systemic therapy has also been found to be particularly effective during severe and complex disorders requiring extensive treatment.