From 12th October 2010 it is a requirement for anyone working with vulnerable groups to be registered with the VBS (Vetting and Barring Scheme) and from November 2010 employers will be legally bound to check and confirm that anyone they employ is registered with the ISA (Independant Safeguarding Authority). The new requirements came about from the Bilchard Inquiry, arising from the Soham murders, and have been put into place to further protect children and vulnerable adults from harm. Although there will now be enhanced checks I would not have thought anyone would be barred for taking an overdose, unless it had for some reason led to a criminal offence. The decision will be up to the police.
The new law which has been introduced is an amendment to the Equality Bill whereby it is now against the law for an employer to ask health questions pre-interview. This is because people with mental health problems have been discriminated against in the past and have not been offered jobs. Are you concerned that this can put a risk to people. I would imagine that if the health issues are serious enough to put people at risk this would be consided after the interview. Certainly if the person had a conviction.