LSD 231
case report says that some types of antidepressants appear to promote flash-
backs among LSD users, and a research study concluded that phenothiazine
tranquilizers worsen flashbacks after they start. Investigations have revealed
that many persons who claim to have LSD flashbacks do not really have them,
that people often use the term casually and incorrectly to describe other types
of experiences. Psychiatrists call the LSD type of flashback “hallucinogen per-
sisting perception disorder.” Some persons, however, regard LSD flashbacks
not as a disorder but as a sign they have learned to achieve altered states of
consciousness without using a drug anymore.
Abuse factors.Tolerance has developed in rats and humans. Humans have
shown LSD cross-tolerance with mescaline andpsilocybinand slight cross-
tolerance withDMT—meaning that the drugs can be substituted for one an-
other, for some purposes at least.
Drug interactions.Two case reports indicate that LSD alone or in combi-
nation withalcoholmay cause muscles to stiffen, accompanied by fever and
insensibility. Some antidepressants can increase LSD’s psychedelic effects;
some others reduce them. Rat experiments show that various opioids in var-
ious doses can either increase or decrease LSD actions and that the schizo-
phrenia medicine clozapine can reduce LSD effects. Case reports say that
chlorpromazine (Thorazine) can cause an LSD psychosis among persons who
have used LSD in the past. Ambroxol, a substance used to help people clear
congested respiratory tracts, can give a false-positive urine test for LSD.
Cancer.LSD stopped breast cancer growth in a rat experiment. Researchers
believe this result came not because of hallucinogenic activity but probably
because LSD reduced amounts of a hormone called prolactin. Animal and
plant experiments show that LSD can be a mutagen, meaning it might have
a potential for causing cancer. A mutagen effect has not been observed in
humans who took LSD under controlled conditions.
Pregnancy.Researchers have demonstrated that LSD passes from a pregnant
mouse into the fetus. In other experiments pregnant mice that received LSD
produced offspring with eye defects. The same happened with rats, but in that
experiment investigators noted no significant statistical difference between
LSD and non-LSD rats in malformations of any type, so the LSD may not have
been responsible for the eye problems. Researchers who gave LSD to dozens
of rats, mice, and hamsters found no proof that the drug caused malformations
in their fetuses (which numbered in the hundreds). In the 1970s claims arose
that LSD causes human chromosome damage and birth defects even if the
drug use stops before pregnancy begins, but subsequent research failed to
verify those claims. Some of the original laboratory tests involved conditions
that do not occur in the human body, and early investigators typically did
not know what drug a woman had actually taken, nor what the dose was,
nor did they consider whether a woman’s health problems promoted congen-
ital malformations. The birth defect rate among children of LSD users is no
higher than the general population’s. A case report notes a woman who took
an LSD dose during early pregnancy with no apparent ill effect on her infant.
A study of pregnant women who attempted to commit suicide with drugs
found no infant malformation attributable to LSD, but the investigators said
data were too scanty to allow a conclusion about LSD’s potential for causing