Research highlights psychosocial factors associated with adverse asthma events. This systematic review therefore examined whether psycho-educational interventions improve health and self-management outcomes in adults with severe or difficult asthma. Seventeen controlled studies were included. Characteristics and content of interventions varied even within broad types. Study quality was generally poor and several studies were small. Any positive effects observed from qualitative and quantitative syntheses were mainly short term and, in planned subgroup analyses (involving < 5 trials), effects on hospitalizations, quality of life, and psychological morbidity in patients with severe asthma did not extend to those in whom multiple factors complicate management.