In the past, it was common for people with symptoms of narcolepsy to go undiagnosed, sometimes for many years. With greater recognition of the condition, and greater awareness amongst the medical profession, the situation is improving, but misdiagnosis of narcolepsy, and thus inappropriate treatment, is still relatively common.
Many people with narcolepsy are able to drive. However, narcolepsy is a condition that may affect your ability to drive safely, and you will be permitted to drive only if DVLA is satisfied that your condition is controlled well enough that allowing you to drive will not cause an unacceptable risk to you and to other people.