Ken is feeling increasingly depressed during his first year of law school. the would likely explain his depression by suggesting that he is no longer intrinsically motivated to pursue his goal of being a lawyer; all his motivations are now extrinsic.

It would be the self-determination theory. He's intrinsic motivation of becoming a lawyer, or as the theory says, the happiness of taking up law is lost. And the mentions of the extrinsic motivation here may mean, the only motivation Ken have for law may be just to earn money, to just finish school or just for the sake of his parents.