5:1

Act and scene of Shakespeare’s Macbeth in which Lady Macbeth is spied sleepwalking

6

Number of diagnostic criteria established by the American Psychiatric Association for sleepwalking disorder

1–7

Approximate percentage of adults who experience a sleepwalking episode, compared with 0.5% who suffer from sleepwalking disorder

10

Number of times more likely that sleepwalking will occur in close relatives of sleepwalkers than in the general public, suggesting a genetic component

6.9

Percentage of sleepwalking reported for girls; 5.7% for boys

15

Age by which occasional episodes of sleepwalking usually disappear without treatment

70

Approximate number of cases of homicidal somnambulism, or sleepwalk murder, reported in history

1846

Year in which the lawyer of Albert Tirrell, accused of murder, mounted a sleepwalking defense

13

Number of sleep medications, including Ambien and Lunesta, for which the Food and Drug Administration has requested added warning language about “complex sleep-related behavioral side effects,” such as driving, making phone calls, preparing and eating food, and having sex while asleep