Star Route 10, Redwood City, Calif.

December 2, 1968

Mr. Joshua Lederberg
San Francisco Chronicle
Sth and Mission

San Francisco, Calif,

Dear Mr, Lederberg:

In your article on the
LSD and chromosomes issue in the Chronicle of Sunday, December lst, you refer
to the study by Cohen, Hirschhorn and Frosch , which appeared in the New England
Journal of Medicine last year,

This paper has a number of
methodological flaws: although the data are presented commendably completely,
there are erros of inference, A re-analysis of the data yields conclusions quite
opposite to those of the authors, I quote from the enclosed review of the literature
to date, by Dr. Joel Fort and myself (to be published in Psychestelic Review #10)

 

"A group of 22 LSD users is reported to have a mean of 13.2% chromosomal
breakage, compared to a mean of 3.8% in a group of 12 non-users, H owever,
we note that of the 22 'LSD-users' not one had used only LSD; all except
3 had used amphetamines, most had used heroin and many phenothiazines
(tranquillizers used to treat mental illness and to counteract LSD). We
also find that the original control groupz contaknés 1) persons, two of
them being eliminated from the data because they had viral infections
shortly after the blood sample was taken, These two individuals had a very
high rate of chromosomal breakage, and if they are exmek included in the
calculations, the mean for the control group jumps to 18.4% breakage, which
is higher than the 'LSD group'. Cohen et al. also give data on a group
of 6 persons who had used drugs other than LSD (amphetamines, opiates,
phenothiazines),The mean breakage rate of this group (not shown by the
authors, byt readily calculable from their data) was 12,6%, One myst
conclude that according to their own data, LSD users do not have a higher
rate of chromosomal breaks than anyone who uses common tranquillizers, or
stimulants, or who meas has had viral infections,"

 

ee or who uses cyclamate
sweeteners, one may perhaps add.

The whole chromosome issue seems
to be a beautiful demonstration of the operations of prejudice in science. Nobody
seems to have even bothered to calculate the mff chromosomal effects of caffeine,
alcohol, or X-ray emitting TV sets that children sit in fromt of for hours.

I enjoy your colum,

Sincerely yours

Ralph Metzner, Ph.D.
Editor, Psychedelic Review