In this paper Bayesian networks modelling is applied to a multidimensi
onal model of depression. The characterization of the probabilistic mo
del exploits expert knowledge to associate latent concentrations of ne
urotransmitters and symptoms. An evolution perspective is also conside
red. Specific criteria are introduced to detect the influence of the l
atent variable on the observation of symptoms. The Bayesian analysis i
s carried out using Gibbs sampling technique which is implemented in t
he BUGS software. The estimation phase leads to the selection of sympt
oms entering into the definition of behavioral syndromes. Results on r
eal data are discussed. The last section deals with simulation experim
ents. Simulation results confirm our methodological choices. Results o
f the paper can enlarge to the central problem of the management of la
tent variables in Bayesian networks modelling. (C) 1998 Elsevier Scien
ce B.V. All rights reserved.