In addition to physical symptoms, parasites are also associated with a wide range of emotional and neurological symptoms. Few studies have devoted much space to this subject. However, one 10 year study into pinworms (threadworms) by Dr Leo Litter was published decades ago (Arch Ped, 1961; 78: 440-55), and remains a standard reference in the field. The children in his study exhibited a large number of behavioural problems, including irritability, insomnia, inability to concentrate, mood swings, unruly behaviour, impatience, impulsiveness, aggressiveness and a short attention span symptoms similar to those of the hyperactive child.
Dr Little suggested that these symptoms were provoked by an allergic response to the parasite. He also noted that children who have parasites showed abnormal brain wave activity, which may also be linked to behavioural problems. Among his patients, there was a remarkable change in behaviour once parasites were cleared from the system.More recently, personality changes have been noted in those with chronic toxoplasmosis (Parasitology, 1996; 113: 49-54). Negative personality traits, noted in men and women, tended to increase with the duration of the infection.