"he is slow as molasses" might be a good way to describe the energy level of people suffering from:

"he is slow as molasses" might be a good way to describe the energy level of people suffering from: major depressive disorder (MDD).
People who got major depressive disorder (MDD), will tend to see everything about their lives as something pointless. This always put themselves in a really bad mood and make them unmotivated to do anything

Yes I did drink plenty of water :)