IAPT have a target of 50% recovery rate (which seems quite low), but does that mean those who do not receive a psychological intervention have lower rates of recovery? Is there any data available on this issue in a report or journal?
Though my response is not directly in response to your question, because where I come from such services are unavailable, my response is my own recovery. So if you can please take a look at some of my writing, it will tell you that only after giving up psychiatric medication (on which I was dependent for 18 years), I recovered. Kindly take a look at the newest article- Musical Progressions too.
50% recovery over what period of time? Not sure about general psychiatric populations, but certainly in those with acute (and chronic) physical health problems, such as cancer, spontaneous recovery rates over one year are higher than 50%.