An effective implementation strategy involves strengthening the primary care organisation with specially trained professionals, e.g. nurses (referred to as care managers in the studies) responsible for support and continual contact with patients suffering from depression; and combining this with other interventions, e.g. education of care teams and feedback of patient data to physicians. Physicians write more appropriate prescriptions for antidepressants, and patients’ symptoms decrease. The effects last for at least 6 months after the completed intervention. We could not determine if the effects last longer since too few studies include repeated measurements. The interventions are cost-effective. The effects of implementation depend on the context and nature of the change process. Hence, studies and systematic reviews should be complemented with methodology that illuminates contextual factors and the implementation process.