Regarding this matter, I've googled and came up with this website, which says:
As verbs the difference [...] is that confined is (confine) while constrained is (constrain).
As adjectives the difference [...] is that confined is not free to move while constrained is within close bounds [...]
With the first paragraph it is that I simply do not understand it grammatically.
I read the second one as confined is stricter than constrained.
Is this correct?
My guess would be that "constrained" may refer to virtually any situation while "confined" is only applied to physical space.