psychotown
A metaphorical state of mind where all sense of decency and morality are lost, and where the wellness, happiness and health of the self or others are no longer a concern, which is open to be visited by anyone with sufficient emotional stimulation (or, quite often, a lack thereof) at their leisure.
She was a weirdo from the beginning, with her cat obsession, her impulsive coffee-bean counting, and her pretty frequent manic outbursts, but when her boyfriend broke up with her, straight-out she took a trip into psychotown's deepest and darkest alleys. (Now picture how the woman in question envisions burning down the houses of the guy and all his family members.)