How can insomnia be described?

Insomnia is best described as the inability to fall asleep or stay asleep. This condition can manifest in various ways, including difficulty initiating sleep, experiencing frequent awakenings during the night, or waking up too early and not being able to return to sleep. Individuals suffering from insomnia may also feel unrested or fatigued during the day due to the poor quality of their sleep.

The other options describe different sleep-related phenomena. The tendency to sleep excessively during the day more accurately relates to conditions such as hypersomnia or narcolepsy. Excessive daytime sleepiness is a symptom that can arise from multiple sleep disorders, including sleep apnea or inadequate sleep, but does not define insomnia itself. Finally, the experience of vivid dreams can occur in various sleep stages and is not specific to insomnia, as vivid dreams might happen during REM sleep in individuals who sleep well. Therefore, the definition of insomnia focuses directly on difficulties with sleep onset and maintenance rather than other sleep disturbances.