Thousands of drivers could find themselves stuck with a hefty fine if they fail to declare medical conditions to the Driver and Vehicle Licensing Agency (DVLA).
Whilst some conditions are more of a given, such as epilepsy and heart conditions, others are rather less obvious.
Eating disorders and Déjà vu also make the list of illnesses that should be declared to avoid being slapped with a £1,000 fine.
Motoring experts at LeaseCar.uk has published a list which the DVLA say they must be told about.
A spokesperson said: "There are some conditions however, that seem too unrelated to even consider spending the time to fill out a form to tell the DVLA about.
"If you suffer a broken limb or severe head injury that affects your memory or ability to perform everyday tasks, you're also probably not going to be able to operate a vehicle safely either.
"In these cases, it seems obvious that you'd have to let the Driver and Vehicle Licensing Agency know about it."
Amanda Stretton, motoring editor at Confused.com, also added: "Knowing which conditions you do and don't need to flag to the DVLA can be confusing. Things that might seem minor, such as headaches and déjà vu, can actually affect your ability to drive safely.
"Many drivers don't realise that an undisclosed medical condition can not only result in a hefty fine, but also invalidate your car insurance. If you're in an accident and you need to make a claim, but you've not notified the DVLA of your condition, this could be a real issue."
The medical conditions that could see motorists hit with a £1,000 fine if not declared:
We often talk about this in passing when we feel like we have seen, heard or said something very similar before as the French terms literally translates in to "already seen".
But surprisingly, it is one of the health conditions that the DVLA say could affect your driving.
However, this applied to medically induced déjà vu which can be associated with certain types of epilepsy.
According to the NHS, a symptom of simple partial (focal) seizures, or 'auras' as they may be known, is "a feeling that events have happened before (déjà vu)."
Sleep Apnoea is a relatively common condition which sees the walls of the the throat relax and narrow during sleep which interrupts normal breathing.