I vaguely recall a study long ago where they took 2 groups of prisoners of the most dangerous kind and did regular blood work on one group giving them vitamin s

I vaguely recall a study long ago where they took 2 groups of prisoners of the most dangerous kind and did regular blood work on one group giving them vitamin supplements. After some months the guards chose to leave all the cell doors open, they were sitting in the hallway in groups playing board games, making music, singing, telling stories. The guards thought it was pretty funny. The other group was still doing their gang warfare, getting into fights, making primitive weapons and killing each other. Lack of D wouldn't be good for the brain. Symptoms of Shortage could be bone pain, muscle weakness, fatigue, cardiovascular disease, asthma etc but those are things you would notice.