“Cannabis acutely induced a transient amotivational state and CBD influenced the effects of THC on expected value. This is the first well powered, fully controlled study to objectively demonstrate the acute amotivational effects of THC.”  http://link.springer.com/article/10.1007/s00213-016-4383-x

“Cannabis reduces short-term motivation to work for money”  https://www.sciencedaily.com/releases/2016/09/160901211303.htm