[tehwalrus]

It worked for me, and it has an evidence base.

Regular exercise stimulates the production of new neurons in the brain, which is a normal process found to be slowed in depressed brains. (the research was presented at a conference, but not yet published as far as I know.)

Mindfullness training has clinical evidence as a treatment for depression, anxiety and other psychological illnesses, as well as having been shown to increase concentration span and effectiveness.

Not everyone has these issues; perhaps I said it wrong. All "normal humans" are subject to depression and anxiety cycles, and have brains that use the same "cognitive energy" for both thinking problems and willpower. Assuming you don't have an abnormality in your brain structure (would be highly unlikely), these techniques will (most likely) help with the problem you describe. Of course, it's only medical science, so it's sometimes wrong for one individual.