Atomoxetine is an NMDA-antagonist and a kappa-opioiod partial agonist, so my guess would be that Atomoxetine is to blame, but probably not metylphenidate.
Hey, sorry for the (very) late reply. I'm on mobile and the interface isn't exactly great, so I can't tell when someone replied to my posts. I just stumbled upon this again by chance.
Yes, it is atomoxetine that caused me chronic DPDR.
But I took metylphenidate once one year before atomoxetine and it caused me DPDR as well, but it was temporary. In fact, the derealization I got from metylphenidate was much closer to what you usually hear from people with this disorder. Without having heard of the disorder before, I said I felt "disconnected/separate from my environment". My derealization on atomoxetine has been very different as a subjective experience. Right now, I feel spaced out/weird/there but not really there.
I have never heard of other reports of people getting DPDR from atomoxetine. Maybe just one (questionable if actual DPDR because of the same nonspecific description as mine, but it was temporary in that case).
I continue to think that DPDR is a group of disorders. I have heard of accounts of people being cured by stimulants. The most obvious way to reconcile the differing medication responses is that the people with this illness are a very diverse group as far as etiology is concerned. Perhaps this is the reason why a treatment is so elusive and we all have to find it by trial and error. The only finding so far that holds for a significant portion of the DPDR patients seems to be kappa opioid receptor dysfunction.
I am still too afraid to go this route because of my negative experience with medication in general. And it would be hard to convince a doctor to prescribe me naltrexone and naloxone just because I say so. I've been to two professors of psychiatry and they both changed the topic when I brought up DPDR. They said atomoxetine can't cause this and that its just adolescence/anxiety. I'm not so sure a doctor would be terribly happy to experiment this way.
I have been prescribed antipsychotics. I took levomepromazine, it made me extremely sleepy, apathetic and generally useless. I certainly didn't help with DPDR, maybe it even worsened it. I took olanzapine once. I took just a quarter of a 5 mg pill. It didn't seem to help, just made me feel "off" and like a zombie. I also developed dangerously high blood pressure. From 1 mg. 1/10 of the usual therapeutic dose. Anyway my baseline blood pressure is super high on its own (150/10).
I also took haloperidol. Just two drops in the morning for a week. That's 1/25 of the usual therapeutic dose according to my doctor. I tolerated it well and it helped significantly with other problems, but I'm not sure about DPDR. I stopped taking it because I already have RLS and typicals are known to worsen movement disorders of this type. But I plan to resume taking it when I'm having stressful periods.