One essential element of integration is "shifting" first-line mental health engagement and treatment tasks to primary care providers. Task shifting requires mental health interventions that fit both the local context of primary care services and the local nature of the problems seen. To date, most adult and child integration models have targeted single conditions at diagnostic levels and relied on additional co-located personnel to provide treatment. To achieve goals of prevention and early intervention, integration models for children and youth must take into account that the symptoms of emerging child and youth problems often suggest multiple possible disorders and can be co-morbid with developmental and parental disorders. By definition, emerging problems amenable to early intervention are likely to be "subthreshold" and not qualify for treatment in a specialty setting, especially when resources are scarce, even though early intervention holds the promise of preventing progression.