MAOB and major depressive disorder: In contrast, MAO-B inhibitor treatment was associated with significantly lower depression symptoms (β = −0.14, 95% CI −0.27 to −0.02, P = 0.026), but not motivation symptoms (β = −0.08, 95% CI −0.29 to 0.12, P = 0.4), on average across all years of follow-up.