In this image, a woman sleeps at Gatwick Airport in southern England, Dec. 7, 2013. CARL COURT/AFP/Getty Images

A 21-year-old U.K. student suffers from a rare neurological disorder which sometimes causes her to sleep for three weeks at a stretch.

Rhoda Rodriguez-Diaz was diagnosed with Kleine-Levin syndrome, also known as “sleeping beauty syndrome,” which causes her to nap for 22 hours a day. At times, her sleeping episodes last for up to three weeks.

“It's really annoying when people call me lazy. I do struggle to deal with the effects of it. But I'm determined to not let it have a big impact on my life. It is one part of me and not who I am. It's frustrating because I can't help it,” she said, Daily Mail reported.

Rodriguez-Diaz said she started sleeping more at the age of 15 and would also end up sleeping in school. Things got worse early 2018 when she suffered from a number of sleep episodes. She was dismissed from school in July 2018 after she failed to show up for a number of examinations. She finally decided to consult a doctor and was diagnosed with the syndrome in late 2018.

Rodriguez-Diaz said she was learning to manage the syndrome and had also re-enrolled to resume her studies.

“I'm more aware of it now. I know when I'm going to have an episode. I used to feel like I was in a dream. It's such a surreal feeling. It feels like you're not really there,” she said, adding, “This is just a hiccup in my life and I am just waiting until it fades out. I want to be taken serious in life and this isn't helping.”

Kleine-Levin Syndrome is characterized by recurring periods of excessive amounts of sleep, which in some cases may be up to 20 hours per day during an episode. These episodes can last for 10 years or more in rare cases. The cause for the syndrome remains unknown.

According to the KLS Foundation, though the syndrome usually affects adolescents, it may also occur in adults and children. At the beginning of an episode, individuals become drowsy. All normal activities stop and the individuals wake up only to go to the bathroom and have food. In addition to excessive sleep, people suffering from the syndrome tend to behave childlike, confused and disoriented. These symptoms persist for “days, weeks or even months” and most individuals are “bedridden, tired and uncommunicative even when awake.”