Which statement best describes insomnia disorder criteria?

• A. Difficulty initiating sleep for 1 month with impairment.
• B. Difficulties initiating/maintaining sleep or nonrestorative sleep with daytime impairment persisting at least 3 nights per week for ≥3 months.
• C. Only 1 night per month
• D. Sleep problems with no impairment

Answer: (B)

Insomnia disorder involves a sleep disturbance (difficulty initiating sleep, difficulty maintaining sleep, or nonrestorative sleep) that causes daytime distress or impairment, occurring at least 3 nights per week for a minimum of 3 months. The statement fits because it includes the possible types of sleep problems, the daytime impairment, and the required frequency and duration. The other options miss one of these elements: one sets a shorter duration, another focuses only on initiating sleep, and another describes sleep problems without impairment.