While visual hallucinations can occur in functional psychotic illness (schizophrenia or affective disorder), they are much more common and indicative of organic disease. The opposite is true for auditory hallucinations. Functional psychiatric illness typically presents in young adulthood—well before age 40. There are strong inheritance patterns for a number of psychiatric disorders, particularly schizophrenia and depression, so family history of behavior disorders can be an important clue. Patients with organic psychosis often manifest some degree of cognitive impairment, delirium, or altered mental status related to their underlying disease process.