Take leave of your senses
Definition 1 of 1
Pro Tip 1/3Emotional Trigger
Used when someone's emotions cause them to act unexpectedly or irrationally. 
When he heard the news, he took leave of his senses and yelled at everyone.
Pro Tip 2/3Temporary Insanity
Suggests a short period of irrational behavior, not permanent madness. 
She took leave of her senses during the argument but later apologized for her words.
Pro Tip 3/3Hyperbole
Often an exaggeration rather than indicating true mental instability. 
He took leave of his senses and bought every lottery ticket in the shop!