The serotonin lie is explained at around the 24 minute mark. 

“Elevations or decrements in the functioning of serotonergic systems per se are not likely to be associated with depression- NMH 1984

“What you see here is the low serotonin theory of depression dying in 1984...So how does it get reborn? It gets reborn in 1987 when Eli Lilly brings Prozac to market....”