Adult Thriller/Mystery. Hispanic or Spanish male Author. Major theme: psychology.

I would have read this in the early 2010's. Got it secondhand at Goodwill. The book detailed the life of the narrator thru flashbacks. I remember psychology/therapy being prevalent throughout the novel. And the narrator eventually being revealed as untrustworthy. The framework for the present day story may have been the narrator providing therapy to a troubled young man.

I would appreciate your help, as I'd like to read this again.