I'm recovered for 90-95% of this illness, I've suffered with HPPD for a period of 5-6 years .
The only thing I suffer from now is chaotic thinking. A good night sleep makes this symptom relative obsolete though.
So what did I do, right?
HPPD really started to fade when I stopped all the drugs. This includes even smoking and probally drinking coffee.
And to eat healthy, and to sport frequently. I think sporting as much as possible is even better.
Also thinking postive is important too, try to go on with your life. Try to hit the hard but "good-for-u" roads frequently.
What I also personally came across, that the cause of increased anxiety is not related to HPPD. HPPD only makes anxiety worse.
Before HPPD kicked in I already had semi social anxiety. Focusing on such pre-existing anxieties is much better then on:"anxiety is from HPPD".
A extra tip:
I know it's really hard to step out your friend group. I think most friend groups who uses drugs frequently posses this strong loyal or tight band thingies. Specially when you're young, this youth culture kinda is your entire world. I think I'm lucky I converted to christianity in that period of time.
I want to say some things about stepping out of such groups. I'm now in my 20's, and now with a more mature mind. I'm really thankfull I'm not in that place anymore. To be frank, I'm attending a good education and hang arround with the good people(I also used to hang arround plain thugs/hoodlums). I know almost certain, If I've stayed in this group I still have HPPD; and I'd be still in that dark corner of society.
Some health boosts:
I was quite desperate in the times of suffering of HPPD. So I played a bit with anti-oxidants.
I discovered that some anti-oxidants helped with HPPD. Which are: L-carnosine, r-fraction alpa lipoic acid and astaxanthine.
This above anti-oxidants has the rare behaviour that it acces the brain. Anti-oxidants, simply said, cleans the body of "waste/dump".
If you're non-functional withouth coffee, you could try as substitute: Acetyl L-carnitine. It's a natural energizer.
If you're having a hard time to stop smoking, ask your doctor if he/she can prescribe champix.
Ps: sorry for my spelling & grammar, I'm dutch.