Sorry, did this as a comment, when I meant to enter it as an answer.
Disclaimer - I'm only a student of Spanish myself.
I believe the "van a (volverme loco)" brings in the extra idea of "they are going to (turn/drive me crazy)" or just "they will (drive me crazy)".
From what i understand, ir + a is a common way to express the future in Spanish. voy a, vas a, va a. In fact, I think you can even concatenate them into voya, vasa, vaa, if not in writing then certainly in speaking.
However, as per disclaimer, don't believe me - wait for confirmation from someone who actually knows what they are talking about... :o)