Is chess a good game for recovering addicts? In this interview to FIDE Master and psychologist Maria Rodrigo the interviewer asked her about chess and addictions:

XL. There are those who are not able to prioritize and get hooked.
M.R. Yes, because the dopamine rush during a game can be brutal. And that is something you have to learn to control. If you don't, you start a game, and then another, and another… And there is no one to stop. You lose hours of sleep… The problem of addiction is more typical in men than in women. Men are more hooked on video games and women on social networks.

I am a recovering addict. I passed through this clinic in Barcelona to recover from my addiction to alcohol and cannabis. They had a group where they used chess as therapy, so as a lover of the game I said to myself that chess couldn't be harmful for my therapy. But they banned me from chess, arguing I played obsessively. They said I could play once my two years treatment is finished. It was true that I played lots of online blitz, but I felt disgusted: why was I banned when they used chess as therapy for others?
Nowadays, I am in the ninth month of recovery. I left the clinic and I went to a psychologist. I don't play online blitz, but I play correspondence and I joined my club to play standard over the board games. My psychologist approve it but he is not specialist in addictions. At the clinic they wouldn't approve I am playing before two years of recovery.
I can read articles like this one on Chessbase where it is said they started a cognitive training through chess at a therapeutic community &quot;recovering the cognitive functions (attention, memory, etc.) deteriorated by drug use, with the help of chess&quot;. But maybe this is focused on teaching how to play chess to people that didn't play lots of online chess while consuming drugs. And dopamine plays a role in addictions. At the clinic they said we were addicts to dopamine highs, so reading FIDE Master Rodrigo I would say it could still be harmful to my therapy and bring me closer to a relapse.
It is clear chess is good to treat other mental diseases like schizophrenia, and it looks good to teach recovering addicts how to play chess to recover the cognitive functions damaged by drug abuse (according to Chessbase article and my clinic), but is chess good for a recovering addict that played chess before his treatment started? Can it bring the patient closer to a relapse in drug use?
Stack Exchange has a site dedicated to medical sciences.
If you open that, you'll immediately see that on the right column there's a disclaimer that you won't find on any other Stack Exchange site. It's a bit long, so let me cut the most important parts:

Stack Exchange Inc., and its sites including Medical Sciences Stack Exchange, is not a medical practice or healthcare provider and does not provide medical advice.
[...]
Consult your own doctor for medical advice.
[...]
Medical Sciences Stack Exchange is for information exchange only, and is not a substitute for medical advice, individualized diagnosis or treatment by a healthcare provider.

This obviously covers the legal aspect, but it's more than that. Even if there were no lawyers and lawsuits in this world, that disclaimer would still have value. Because, well, it's true. In general you cannot trust users on any of these sites to really know what they are saying. Your health is too important to blindly trust some random stranger on the web, no matter how high their reputation is or how sincerely they are trying to help.
Besides, it seems to me that you've already got the answer from your clinic:

But they banned me from chess, arguing I played obsessively.

I'm sorry, but I'm afraid you'll have to accept it.
I hope I won't sound judgmental if I tell you that what you are really doing here is not looking for an answer (you've already got one; only, it's one you don't like), but rather for an excuse that will let you keep playing and ease your conscience.
Imagine someone posted an answer along the lines of

Don't worry, those doctors don't understand anything! Playing chess can't be a problem, just go ahead and play as much as you want!

I suppose you'd be very happy to read it. And yet, who would you rather trust: the doctors that visited you and know your case specifically, or someone who probably has no idea what they are talking about, and who certainly doesn't know you, your clinical history, anything about you at all?
So do the right thing, and do what your doctors say. Or in any case discuss with them what you should do.
My best wishes for your full recovery!