This review updates a similar paper published in this Journal in 2000. It presents evidence from meta‐analyses, systematic literature reviews and controlled trials for the effectiveness of couples and family therapy for adults with various relationship and mental health problems. The evidence supports the effectiveness of systemic interventions, either alone or as part of multimodal programmes, for relationship distress, psychosexual problems, domestic violence, anxiety disorders, mood disorders, alcohol abuse, schizophrenia and adjustment to chronic physical illness.