Efron & Odom READ OUR THUMBS ... No Drug Problems Here!

10/16/2013 4:18 PM PDT

Zac Efron
and Lamar Odom haven't let their cocaine problems drag them down completely -- in fact, they're both trying to stay positive ... flashing thumbs up signs in L.A.

Having a positive mental attitude is an important first step. Let's just hope they don't crack.