There is a pressing need for effective interventions to treat mental health disorders in children and youth. There is evidence for increasing incidence rates across a wide range of conditions, and these can lead to very significant long-term impacts. They include depression, anxiety, abuse of drugs and alcohol, and the impacts of a variety of traumas. Recently we have carried out a number of studies in which complex and multimodal interventions were either introduced and then studied, or were on-going but hadn’t previously been rigorously tested for efficacy. Here we present a review based upon some of these multimodal programs which examined outcomes in: (1) a schoolbased program to reduce depression and suicidal thinking in youth aged 11-17 years old in which all students were screened on an electronic tablet using standard scales for depression and suicidal thinking followed by the option of an internet-based cognitive behavioural program; (2) a screening, brief intervention and referral to treatment (SBIRT) program to help youth aged 11-17 years old who had significant drug and/or alcohol abuse in which initial screening for drug and alcohol use was followed by the options of an internet-based cognitive behavioural program and referral to child and adolescent specialists; and (3) outcomes following trauma experienced by children aged 5-12 years old in two separate programs in which a complex intervention was used involving 2-3 hours of weekly interventions for both the child and a primary care-giver.