Since Cohen, Marinello & Back (1967) first reported an effect of LSD on human chromosomes, several workers have shown an increased frequency of chromosomal abnormalities in leucocytes in patients who have been treated with the drug or who have illegally taken it (Cohen, Hirschhorn & Frosch, 1967; Irwin & Egozcue, 1967; Nielsen, Friedrich, Jacobsen & Tsuboi, 1968; Hungerford, Taylor, Shagass, La Badie, Balaban & Paton, 1968). Other workers were unable to demonstrate any effect of the drug on the chromosomes in human leucocytes (Loughman, Sargent & Israelstam, 1967; Bender & Siva-Sankar, 1968; Sparkes, Melnyk & Bozzetti, 1968). Experimental investigations have given preliminary evidence of an effect of LSD on meiotic chromosomes in mice (Skakkebæk, Philip &
An official journal of
