perder un tornillo

1.
SpainLatin Americaneutral
- To lose a screw (literally, as a mechanical component).
2.
SpainLatin Americainformalcolloquialjocular
- To become mentally unbalanced or behave irrationally; to 'go crazy' or 'lose one's mind' (used humorously or pejoratively).

Examples:

ES: Donna está a 2 ó 3 días de perder un tornillo.
EN: That way the two stories don't get mixed up.
ES: Wow, me siento tan loco, ¡voy a perder un tornillo!
EN: You can't go back on your word later, huh? Mom, when do you want me to start?
ES: Sí, pero probablemente no cuando tengo una adolescente histérica volviéndose loca por una plaga de piojos y estoy a punto perder un tornillo.
EN: Yeah, but probably not when I've got an hysterical teenager freaking out about head lice and I'm about to do my nut!