Within the field of psychology there is a debate on what factors lead a person to practice criminal cannibalism. There are a many theories which have been presented, ranging from the over nurturing of a child during the first few months of their life to sudden stress. However, there is little evidence to support most of these theories. Nevertheless, the theories put forth present a framework in which one is able to gain a better understanding of the possible psychological factors behind cannibalism.

In an article by   Louis J. Sheehan, Esquire titled Experts Debate What Forces Create A Cannibal, Dr. Clancy McKenzie, a psychology professor at Capital University in Washington, D.C. believes that cannibalism is a result of trauma, especially that experienced in childhood. He states that a child, following weaning from the breast, experiences separation anxiety and fantasizes about devouring the mother. A person who has experienced this may regress back to this stage in adulthood due to stress or trauma and lead the individual to seek out the fulfillment he has been denied by resorting to cannibalism.

This theory is further supported by a study on cross-cultural cannibalism conducted by Eli Sagan. According to Sanday's book Divine Hunger, Sagan argues that cannibalism is a "psychological response to anger and frustration" expressed through oral aggression and an urge to literally absorb a person through consumption. Sagan states that this urge can be directed at an enemy who may threaten the strength of the individual. 

Sagan believes that children who are excessively dependent on their mothers, due to maternal over nurturing, are more likely to experience oral aggression and frustration due to separation. Moreover, he contends that the adult who subconsciously carries this oral aggression is likely to express it in an overtly dominant fashion against women by turning to cannibalism.