So how hard would that be? The police over here appear to have no problem doing just that. I frankly do not see why somebody applying for a firearms licence shouldn't be required to go to a doctor and get a certificate declaring they are mentally fit. What illnesses would be considered as grounds for refusal, well obviously schizophrenia would be top of the list as would bipolar disorder, drug addiction, psychotic behaviour, suicide attempts and personality disorders. Obviously to be truly effective, the certificate would have to be renewed periodically. Even better, the onus should be on doctors to report any future behaviour to the police to update their records with financial penalties for not doing so.