Histadelia, is more common in males and is characterized by elevated blood levels of histamine. It is estimated that 15-20% of schizophrenics are probably histadelic. This is also known as an undermethylation problem or being under-methylated. This condition is characterized by low levels of serotonin, dopamine, and norepinephrine, high whole blood histamine and elevated absolute basophils. This population has a high incidence of seasonal allergies, OCD tendencies, perfectionism, high libido, sparse body hair, and several other characteristics. In severe cases involving psychosis, the dominant symptom is usually delusional thinking rather than hallucinations. They tend to speak very little & may sit motionless for extended periods. They may appear outwardly calm, but suffer from extreme internal anxiety.

The treatment of histadelia requires great patience because six to ten weeks are often needed before the beginning of significant improvement. The treatment usually takes twelve months to complete. To find out more about this see Mental Illness: The Nutrition Connection, a book by Carl Pfeiffer. The prognosis is good if the histadelic patient cooperates with treatment and works to give up detrimental addictions.