[WilTimSon]

Ah, okay, that makes sense, thank you for clearing up my confusion. Basically, they're looking for the most effective substances to boost activity, which is one of the things that anti-depressants are supposed to help with.

[mattkrause]

It’s more that substances boosting activity also help with depression: nobody really knows the causal direction, or even if there really is one.

That said, one way to botch these assays is to do something that just directly increases locomotion. They did look at that in Table 1 though.