Psychological sleep disorders: Pathology review

A 25-year-old graduate student comes to the physician for evaluation of excessive sleepiness over the past year. He is often sleepy during the day and frequently falls asleep during class. These episodes occur nearly daily and have been negatively affecting his grades. The patient goes to bed at 10 PM and wakes up at 7 AM. Last week, during an argument with his partner, the patient suddenly felt weak in the legs and collapsed onto the floor. The patient does not consume alcohol or recreational drugs. He has not experienced a loss of interest in his normal activities and does not have suicidal ideations. Vitals are within normal limits. Physical examination is unremarkable. Which of the following additional features is likely to be present in this patient?