Claustrophobia

"You have a fear of enclosed spaces (probably because of the mutants that live there). You gain +1 to SPECIAL attributes when outside, but suffer -1 when indoors."

- Fallout:New Vegas description

Claustrophobia is a trait in the Fallout: New Vegas add-on Old World Blues.

Effect
When outside you gain +1 to all SPECIAL stats but when indoors, you suffer -1 to all SPECIAL stats.

Despite the description, there are some "outside" places where you will suffer the -1 SPECIAL penalty. This includes places such as The Strip and Freeside.