CNN’s Vital Signs profiles a woman who suffered from hypersomnia and whose sleep disorder symptoms were alleviated by Emory neurologist Dr David Rye.

After years of research, Dr Rye and his team found that some patients have a hyper sensitivity to a naturally occurring sedative in the brain, known as GABA. Essentially, the hyperactivity of GABA in a patient’s system acts as a “parking brake,” no matter how much “acceleration” is applied from stimulants.