LSD and chromosomes

The effect of LSD on chromosomes is still a matter of controversy. Continued experimental therapy does not seem strongly contraindicated. However, care should be taken that LSD is not administered to pregnant women. There is evidence, based on chromosomal and autoradiographic studies, that LSD easily penetrates into the fetus. It has also been shown that LSD has antimitotic properties. The increased incidence of spontaneous abortions in LSD treated mothers may reflect a possible teratogenic action of the drug. In the study of the effects of LSD on chromosomes, there are three main flaws that should be taken into account. First, cultured lymphocytes are commonly used in such studies. However, stimulated lymphocytes seem to be extremely labile, and chromosomal abnormalities can be produced in them by practically any substance. Second, several of the studies on mitotic chromosomes include gaps as an abnormality. In most cases, however, such gaps correspond to the light regions of G banded chromosomes as we know them today. Also, some of the bi armed chromosomes seen in mice studies may just be the result of an optic effect. A centromere association of two acrocentrics, or the apposition of two chromosomes with widely separated chromatids may appear as metacentric chromosomes, especially if one is looking for anomalies. Finally, some of the 'abnormalities' described are just normal morphological characteristics of some chromosomes. The 'gap' previously described in the X chromosome of mice is one such characteristic, and if its normal presence is not known, it may even be scored as a double break. For any future studies of drug effects on chromosomes, it is important that such sources of error be eliminated by carefully choosing the test situation to be used, by complete identification of all 'abnormalities' observed and especially through a complete knowledge of the normal characteristics of the animals used in the study.