Sleeplessness without identifiable medical or psychiatric cause is best described as which type of insomnia?

• A. Secondary Insomnia
• B. Circadian Rhythm Disorder
• C. Primary Insomnia
• D. Insomnia Disorder

Answer: (C)

Sleeplessness without an identifiable medical or psychiatric cause is described as primary insomnia. This labeling rests on the idea that the sleep difficulty stands alone, not explained by another medical condition, psychiatric disorder, or a circadian misalignment. When a clear cause is identified—such as pain, anxiety, or another medical illness—the pattern would be categorized as secondary insomnia. Circadian rhythm disorders involve a timing issue with sleep-wake cycles, not just unsatisfied sleep that lacks a known cause. The broader DSM-5 term insomnia disorder covers persistent sleep difficulties causing distress or impairment, but in the absence of any identifiable cause, the traditional label used is primary insomnia.