“…As far as treatment delivery is concerned, interventions were administrated by external experts (23, 26-30, 33, 34, 36, 37, 39, 41, 43-47, 50-52, 54, 55, 57, 59, 60, 62-65, 68, 70-74) or trained staff (31), and in many cases by experts, together with the involvement of staff members (21,22,32,38,40,48,49,53,56,66,67,69,77). Apparently, the cooperation/involvement of an external expert had no impact on treatment effectiveness.…”