Many myths exist about schizophrenia. People with this disorder are not intellectually disabled, nor do they have "split personalities." While some may show aggression during an untreated acute episode, it is rare and unlike the media's portrayal of serial killers or psychopaths. Symptoms often first appear when a person is between 15 and 30. Schizophrenia rarely manifests in children under 12. Symptoms can emerge abruptly or progress gradually, possibly without the person's immediate notice. These vary between individuals and can change over time. Some people have a single psychotic episode, while others experience multiple episodes throughout their lives.