Abstract
The authors present several new regulationsincluded in the 1983 canon law code dealingwith the legal and mental prerequisites forvalid or invalid marriage (canon 1057). They alsodiscuss the psychological aspects of marital capacitylaid out in canon 1095. They point out severalreasons underlying mental incapacity for performingsignificant marital duties: sexually-related personalitydisorders which preclude the exclusivenessand natural consumption of the marital agreementand non-sexual personality disorders which precludeadequate interpersonal relations.