MRCP2-3787
A 25-year-old man with insulin-dependent diabetes mellitus (IDDM) visits the neurology clinic complaining of recurrent episodes of collapsing. These episodes involve a sensation of weakness that causes him to collapse to the ground. The episodes began about 8 months ago and happen multiple times a week. He does not believe that he loses consciousness during these episodes and has observed that emotional situations, particularly when he is laughing, can trigger the attacks. He has been feeling anxious and depressed lately, sleeping poorly with frequent nightmares.
His diabetes control has been poor in the past few months, and he has recently altered his insulin regimen to try to achieve better control. He has a sister who has a history of febrile convulsions.
What is the most probable diagnosis?