My understanding of integration of primary and mental health care is not just coordination of care / talking to primary providers but rather a dedicated system designed to provide mental health care fully in the primary care office setting. The jist of it is hiring someone with training in mental health evaluations (such as a LICSW) who can see patients in the primary care office who are identified as needing more intensive mental health services by the PCP and having the PCP evaluate and initiate treatment as well. A designated psychiatrist would then review the caseload of patients being cared for under this model (without seeing most of them) and make recommendations about their treatment. The psychiatrist would only see a very small percentage of the reviewed individuals who need significantly more input, and typically just as a consultation.
I hope I am not butchering the general idea because I have only heard it presented at a conference and have not worked in any of these models, there is a lot of research coming out of UWash utilizing this (or a similar) model and showing better mental health outcomes in the primary populations served versus treatment as usual. It also seems that this model may actually save money. Personally I think based on the preliminary data that the model may make some sense. All of us going into our careers should know, though, that this is a radically reinvented practice model and not merely a statement that treating physicians should work together on their patient's care (which is a well-established ideal even if it does not always happen in real life).