After a LSD trip of about 175 ug (with a relatively low body weight), I experienced HPPD symptoms for the next couple of days, including persistent river-like movement of patterns and a sense of depersonalisation. I know the time frame of three days after the trip is not long but I still found it remarkable that the symptoms completely disappeared after I had an epileptic seizure. As far as I understand, psychedelic drugs change neural brain structure during a trip in a way that certain connections within the brain, which are normally inhibited, now connect, causing new sensational perceptions. If the brain, maybe due to too high amounts of stress experienced during the trip, does not manage to properly process the changes and fully restore the previous condition, it might get stuck in the imbalance and, therefore, certain symptoms of the trip persist afterwards. Apparently, it has been observed that seizures, which are accompanied by a high release of neurohormones and neurotransmitters, can restore balances of neural brain structures leading to an improvement of mental conditions such as depression. This is why artificially created seizures are still successfully used in electroconvulsive therapy for the treatment of mental disorders. In my case, the seizure might had a similar effect and kind of reset my brain to its previous neural balance. This is just an idea based on my own experience and articles I have read online but I would be curious to hear other thoughts on this and maybe similar experiences. I want to be optimistic that when a drug is able to change the perception in such a persistent way like in the case of HPPD, that there must also be a way to restore the normal perception. To all those who are suffering, stay strong.