If you have been diagnosed as a sufferer of a sleep disorder (Including Obstructive Sleep Apnoea syndrome causing excessive daytime / awake time sleepines), it is your legal responsibility as the licence holder to inform the DVLA. This is because the risk of driving accidents are significantly increased, amongst drivers with a an untreated sleep disorder resulting in reduced vigilance and falling asleep at the wheel. Whether Group 1 or Group 2, the DVLA must be informed, if you fail to do so you will be committing an offence.

Private cars (Group 1 entitlement)
Driving must cease until satisfactory control of symptoms has been attained, confirmed by medical opinion.

PSV/HGV (Group 2 entitlement)
Driving must cease until satisfactory control of symptoms has been attained, with ongoing compliance with treatment, confirmed by consultant / specialist opinion. Regular, normally annual, licensing review required.

If you are in any doubt, you may contact the Drivers Medical Unit, DVLA, Swansea, SA99 1TU, T: 01792 783 705.

Insurance
Remember that your insurance company along with the police can request medical details for any condition for which you are either under medical investigation or currently under treatment, following a severe accidents. If a condition for which you have been diagnosed can affect your ability to drive safely is undeclared, your insurer may refuse to support any claim. Please inform your insurer if you are diagnosed with a medical disorders.