Mental disorders in commentaries by the late medieval theologians Richard of Middleton, John Duns Scotus, William Ockham and Gabriel Biel on Peter Lombard's Sentences.

In their commentaries on the Sentences, Richard of Middleton, John Duns Scotus, William Ockham and Gabriel Biel reflect whether mentally-disturbed people can receive the sacraments (Baptism, Eucharist, confession, marriage) and fulfil juridical actions (make a will or take an oath). They consider that the main problem in 'madmen' in relation to the sacraments and legal actions is their lack of the use of reason. Scotus and Ockham especially are interested in the causes of mental disorders and the phenomena which happen in madmen's minds and bodies. In considering mental disorders mostly as naturally caused psycho-physical phenomena, Scotus and Ockham join the rationalistic mental disorder tradition, which was to become dominant in the early modern era and later.

Late medieval philosophical and theological discussions of mental disorders: Witelo, Oresme, Gerson.

No matter from which perspective Witelo, Oresme and Gerson approach mental disorders, they think that madness usually has a bodily, such as a humoral or organic, origin. They do, however, consider divine or demonic causes as possibly being behind immediate causes. According to Witelo and the Parisians, because of a change in the body, madmen's sensory fantasy is disturbed and in this situation their intellect does not act normally, and their will lacks freedom. It is important to realize that, according to the medieval writers, mentally-disordered people have not lost any parts of their soul or their basic potencies. If this were the case, they would not be human beings by definition.