A chief problem in the diagnosis of chronic brucellosis is the evaluation of psychological factors in the disease. The infection (particularly the cerebral form) may simulate psychoneurosis or psychosis. The disease is often complicated by neurotic tendencies of the patient. Various psychological illnesses present the same protean appearance as chronic brucellosis and lead to an erroneous diagnosis of the disease. Psychiatric and projective psychological techniques are useful for diagnosis and evaluation. The authors state that certain psychological characteristics are very frequent in brucellosis; however, those they list are vague and general—for example, feelings of sexual inadequacy and suppressed aggression.