LSD/Ecstasy drips down the spinal cord and causes flashbacks

   LSD and Ecstasy, among many other drugs, has been said to linger in the body and then cause permanent lasting effects for the rest of the user's life. This is un-true. All drugs, and all substances (except some heavy metals like mercury or lead) are metabolized/removed from the body in a certain period of time. There is no substance that can be eaten, smoked, inhaled, or consumed and then get stored permanently in the body, because the human body is almost constantly replacing the nutrients and minerals in every cell.

    Flashbacks, or analepsis, are a peculiar phenomenon, which cannot yet be fully explained. The term is defined as a "psychological phenomenon in which someone remembers a past experience". When describing flashbacks in regards to psychedelic drugs, they are usually defined as due to Hallucinogen Persisting Perception Disorder (HPPD). The cause of HPPD is unknown. Some theories are that HPPD is due to genetics, and is therefore hereditary. Another theory is that HPPD is caused by traumatic stress or emotionally intense experiences, where the subject is acutely reminded of the experience.

    The causes of flashbacks are not due to any drug staying in the user's body. All drugs are removed from the body in a certain period of time, usually a couple days. Metabolites of marijuana stay in the user's body for the longest period of time, which can be up to about three (3) weeks. They are not psychoactive at this time.

Sources:

1. http://www.biopsychiatry.com/seromyst.htm

2. See, for example, Abraham HD, Aldridge AM (1993). "Adverse consequences of lysergic acid diethylamide". Addiction 88 (10): 1327-34. PMID 8251869.

3. Blumenfield M (1971). "Flashback phenomena in basic trainees who enter the US Air Force". Military Medicine 136 (1): 39-41. PMID 5005369.

4. Naditch MP, Fenwick S (1977). "LSD flashbacks and ego functioning". Journal of Abnormal Psychology 86 (4): 352-9. PMID 757972.

5. Halpern JH, Pope HG Jr (2003). "Hallucinogen persisting perception disorder: what do we know after 50 years?". Drug Alcohol Depend 69 (2): 109-19. PMID 12609692.; Halpern JH (2003). "Hallucinogens: an update". Curr Psychiatry Rep 5 (5): 347-54. PMID 13678554. [1]