Update 6/11/2019 - The article has been published: Lewis, DM, Faces of HPPD: Hallucinogen Persisting Perception Disorder Patient Survey Results and a Descriptive Analysis of Patient Demographics, Medical Background, Drug Use History, Symptoms, and Treatments. Addictive Disorders and their Treatment. Forthcoming 2019.
Update 3/16/2019 - The manuscript was submitted to a respectable peer-reviewed journal focused on drug disorders. If accepted, it will be approximately 3 months until publishing. I will update this website as soon as information is known.
Data Collection for the HPPD Survey has been completed as of December 30, 2017. A hundred thousand thank yous to the folks who partook in the survey to help foster knowledge about HPPD. It has taken years to collect data from a rather small population of HPPD patients.