  We study quantum caustics in $d$-dimensional systems with quadratic
Lagrangians. Based on Schulman's procedure in the path-integral we derive the
transition amplitude on caustics in a closed form for generic multiplicity $f$,
and thereby complete the previous analysis carried out for the maximal
multiplicity case $f=d$. Multiplicity dependence of the caustics phenomena is
illusrated by examples of a particle interacting with external electromagnetic
fields.
