A woman with severe daytime sleepiness was able to enjoy a social life and use public transit after a dog was trained to wake her up regularly.

Dr. Olivier Le Bon, head of the psychiatry department at Tivoli Hospital in La Louvière, Belgium, describes the dog tale in Thursday's lighthearted holiday issue of the British Medical Journal.

Idefix the guide dog (Courtesy Dr. Olivier Le Bon)

"Unfortunately the patient, although very bright and courageous, is still far too irregular and sleepy for a steady job," Le Bon said in an email.

"The real difference is for her social life."

The 35-year-old with bipolar disorder had suffered sleep attacks up to six times a day and she'd sleep up to 16 hours a day when depressed.

If she tried to use public transit, she'd usually fall asleep within minutes of sitting down, doze until waking at the end of the line and then fight sleepiness on the way back, said Le Bon and co-author Paul Linkowski, head of psychiatry at Université Libre de Bruxelles.

Doctors tried treating her with various medications including antipsychotics and antidepressants, but her symptoms were only partly controlled.

Then she was referred to a charity that provides trained dogs for people with visual or hearing impairment.

It took a year to fully train the dog, named Idefix.

Idefix was first trained to wake up the patient in the morning at the sound of an alarm clock — even if it took 30 minutes of gently biting.

Eventually, he learnt to wake her up, if needed, at every public transit station.

"The paper was written to share the idea of this new treatment with other clinicians," Le Bon said.

The severe condition is rare, he said. In Le Bon's 25 year career, he's only known a handful of cases.