DOUBLING UP

New Scientist is to be commended for its much-needed review of
discrepancies in the politicised field of ecstasy research (20 April, p
26). In addition to the issues mentioned, there is also a worrying tendency
for some ecstasy researchers to base multiple publications on a single set
of participants. Because these researchers typically fail to acknowledge
this practice, it creates the false impression that separate papers are
mutually confirmatory.

For example, in addition to their paper in The Lancet (vol 358, p 1864), L.
Reneman and colleagues simultaneously published another paper in the
Archives of General Psychiatry (vol 58, p 901) also describing the
estimated cortical serotonin transporter density in almost entirely the
same volunteers. Neither paper acknowledged the existence of the other.

This is no small matter. In future, authors will undoubtedly cite both
papers as if they were independent evidence that ecstasy exposure reduces
serotonin transporter density.

The pressure on academic researchers to divide work into "least publishable
units" in order to appear productive is lamentable, but understandable. But
I find the failure of these pressured researchers to properly cite these
papers and their relationship harder to understand.

Matthew J. Baggott

San Francisco