There is now a considerable literature on Hg amalgams. The consensus is not
really formed; but 'mad hatter' disease is the outcome of chronic and *high*
levels of exposure to mercury vapour as well as to cutaneous exposure. Mania,
rather than depression, is the behavioural outcome of this type of mercury
toxicity owing to to the CNS toxicity of the compounds used.
A literature search of Medline using 'mercury' and 'amalgam' and 'depression'
or Hg, amalgam and 'psychological' would be the most definitive way to skim
through current opinion on the subject! (and easy if the questioner has access
(Dr.) Katherine J. Kaye
kkaye at vax.ox.ac.uk