Working a bit from memory here, so don't quote me.
As I remember it, there were a significant number of unintentional suicides especially among young girls. The problem with paracetamol is that for the first few days everything is fine then the lived fails often over 3 or so weeks. It was apparent that many of these people didn't really understand what they were doing, and really suffered a combination of remorse and terror while gradually dying. Case series showed that the number of tablets consumed depended more on ease of access than intent. The other problem was a number of accidents among children, eating lovely white sweets lying around. I don't believe there was anything more rigorous than that, save to say paracetamol overdose has become very rare in the UK now.