Blueflame - seriously, stop posting.
Laura, Massa and Kubica all had (have) mental AND physical issues. Lauda lost several pints of blood (plasma at least) in his return races, and had a slightly more dangerous era to compete in than the unthinkably safe today. Massa had the least physical issues, but who knows what the skull damage did to reflexes, eye coordination etc. Not enough to fail his F1 medical, but maybe enough to stop him competing at the front (~0.2% change for instance).
Kubica has a difficult task ahead. Not only has he got to, in the very depths of his psyche, not be worried about crashing again - which I doubt any normal person can manage, but he also has to get the arm, the nerves, the muscles and the brain all working in unison. If he loses @0.2% ability, then it's the difference between a great and an also ran.