Described herein are compositions which include digestive enzymes and which are formulated to reduce one or more symptoms of a neuropsychiatric disorder. Also described herein is a method for treating an individual with a neuropsychiatric disorder using digestive enzymes and their derivatives to alleviate the symptoms of neuropsychiatric disorders. The method comprises administering to the individual an effective amount of digestive enzymes that are either naturally or recombinantly derived, or their derivatives, in an amount effective to reduce one or more symptoms of the neuropsychiatric disorder.