13. Caligula’s Extreme Paranoia Led him to Make his Horse a Senator
Nephew of Tiberius, Caligula is speculated to have suffered from paranoia, antisocial personality disorder, and narcissism. To begin with, he believed he was a god and that the god of the sea, Poseidon, was plotting against him. In arguably his most insane moment ever, he made his horse a senator, while he saw nothing wrong with marrying his own sister. According to historical sources reported by Philo of Alexandria, his mental health dramatically changed suddenly after a severe fever that nearly killed him in 37 AD.
Many modern scholars suggest that it was his physical illness that led to severe mental issues. His symptoms could indicate any number of mental health illnesses, from schizophrenia to personality disorder. Even Suetonius admitted that “he was sound neither of body nor mind,” constantly running in fear of thunder and lightning, and from the gods, he claimed not to believe in. In his time, he was diagnosed with falling sickness, known in modern times as epilepsy, which very well could have led to mental illness later on in his lifetime.