Less Than Zero (1987)

Returning home from college for Christmas vacation, Clay (Andrew McCarthy) is eager to resume his long-time romantic relationship with Blair (Jami Gertz) and his old friendship with the irresponsible Julian (Robert Downey, Jr.). But he finds the two have started a relationship of their own and developed a fondness for clubs, wild parties and endless amounts of cocaine. Clay's determination and love for Blair enables him to win her back, but Julian is a different story. Increasingly hopeless, addicted and deeply in debt to his dealer (James Spader), he puts Clay and Blair through the ultimate test of friendship, loyalty and love.