Quote from : Entheogens and the Development of Culture: The Anthropology and Neurobiology of Ecstatic Experience Book

The effect of hallucinogenic mushrooms on the user's experience and behavior depends in part on his or her personality and genetic predisposition, which can vary to a great extent from person to person. As symptoms of psychiatric disorders can sometimes be elicited after one-off use, people with a genetic tendency to depression or psychosis should be discouraged from using psychoactive mushrooms.