Here is a post that might interest you by Paolo Terni on his blog: Distinctions: SF and Positive Psychology.
Recently, I participated in some online conversations about SF and how it is perceived. I agree with Kirsten Dierolf and with Coert Visser that there is some confusion about what Solution-Focus is. As Bion would say, the term has become so saturated with meaning to be of ncreasingly little use as a descriptive term. Much of the confusion surrounding SF practice seems to stem from a single word that is often used to (mis)characterize SF: “positive“. I decided to make a few distinctions that I will be posting in the next few days to help us get untangled from this trap that our language has set for us. Read more.
Also read: Positive psychology, the strengths movement and the solution-focused approach