Somnolence

A pathological state of excessive sleepiness characterized by an abnormal propensity to fall asleep, decreased level of alertness, and difficulty maintaining wakefulness during usual periods of activity, distinct from normal pre-sleep drowsiness or fatigue. Possible causes are sleep disorders (sleep disruptions, obstructive sleep apnea, narcolepsy, restless legs syndrome), medications (sedatives, antihistamines, antidepressants, opioids), mental health conditions (depression, anxiety, chronic stress), hypothyroidism, anemia, diabetes, multiple sclerosis, chronic pain, and previous head trauma.