How long can flashbacks occur after magic mushroom use?

Hallucinogen Persisting Perception Disorder (HPPD) is a rare condition in which people experience flashbacks or "hallucinogen persisting perception disorder" after taking hallucinogenic drugs, such as magic mushrooms or LSD. HPPD can cause people to see patterns, colors, or objects that aren't really there. It can also cause anxiety, paranoia, and difficulty sleeping. HPPD is thought to be caused by damage to the serotonin receptors in the brain. Most cases of HPPD resolve within a few weeks or months, but some people may experience symptoms for years or even decades. There is no cure for HPPD, but treatment can help people manage their symptoms. Treatment options include therapy, medication, and lifestyle changes.