Alcohol and fatigue studies have PROVEN that the often chronic fatigue experienced by many, many pilots is akin to flying while drunk. However, because managements and the government have little or no interest in further restrictions of flight crew FT/DT, then we are not routinely "screened" for fatigue, only drugs and alcohol! Ironically, it is often those two things people revert to in order to TRY and recover some level of normalcy through "forced" sleep brought on by their effects.