LSD and genetic damage. Is LSD chromosome damaging, carcinogenic, mutagenic, or teratogenic?
Dishotsky NI, Loughman WD, Mogar RE, Lipscomb WR
Science, 1971; 172:431-440

Review/Synopsis by Doug Fraser

Sixty eight studies (between the years 1967 to 1971) were reviewed to see if there was any consensus as to the effects of LSD with respect to different types of genetic damage. These types include chromosome breakage, carcinogenic and mutagenic changes, and teratogenic effects on fetuses. Each section below briefly summarizes the findings of the authors, their views on the flaws in the studies, and the conclusions on why pure LSD, when ingested in moderate doses, does not cause any type of genetic damage.

Two types of research studied the breakage of chromosomes exposed to LSD - in vitro and in vivo studies. First, no consistent dose-response relation was found in analyzing the in vitro studies. Damage was only reported at high doses or prolonged exposure to LSD, contrary to what would be expected in vivo. Also, the kind of damage most reported (chromatid-type) and the level of it is similar to that induced by a wide variety of factors. Examples of these factors include technical procedures, changes in temperature or pressure, or exposure to any number of substances. Third, the human body has the ability, unlike single cells, to detoxify and excrete noxious compounds. So it is not automatic that something toxic in vitro would be in vivo as well.

As for the in vivo studies, they can be divided into two groups based on the type of LSD the subjects ingested - pure and illicit LSD. It is seen that the illicit LSD users had a much higher chromosome breakage rate. This could easily be attributed to the fact that black market LSD is hardly pure or even LSD at all (as a number of studies have shown) and also to the fact that most of the subjects in these studies were polydrug users or abusers. So it is certainly not definite that the LSD was the factor causing the genetic damage. This is supported by the fact that in the other type of studies, with pure LSD, over 80% of all the subjects showed no chromosome damage at all. The studies that did find some damage had possible methodological flaws as well.

Studies that speculated LSD was a carcinogen were based on the comparison of the specific type of damage (presumably) induced by LSD and the type of damage seen in leukemia patients. But the evidence was scanty and any connections tenuous, so the authors of this paper concluded that there was no definite evidence that LSD is a carcinogen. As for mutagenic effects, based on the studies done on drosophilia and fungi, the idea that LSD could be a mutagen was soundly discounted. Only at extremely high doses (equivalent to a 30 x 10 to the power of 6 ug dose for a 70kg man) did any mutagenic effects appear.

However, teratogenic effects were seen in the studies examining LSD and such things as congenital malformations, fetal wastage, and spontaneous abortions. But a significant factor here is that rodents were the primary research subjects in these types of studies - information related to humans and primates was scarce. Generally, very high dose of LSD were shown to disrupt pregnancies in various ways (and only early in the pregnancy) but no teratogenic effects could be found in the offspring. In addition, there was a wide variation of susceptibility based on the strain and the species of the rodent. The important factor to consider here is that there are significant biological differences (with respect to gestation) between humans and rodents that make rodents more sensitive to the teratogenic potential of a substance.

In the case studies of the illicit use of LSD by pregnant women, some children were born with various types of deformities, but the factor of other drugs of abuse was more likely a better explanation - very little data existed to make any good conclusions. But studies of spontaneous abortions did show a possible correlation, so pregnancy is certainly a contraindication. As for germ cells exposed to LSD, the one study of this kind showed no effects.

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