Once I snapped him out of it, he was right back to normal. Although...

[She hesitates - that other matter has nothing to do with the river's effect on him, does it? But it's worth sharing regardless, if only to warn Need of the phenomenon.]

The reason he fell in in the first place is that he thought he saw somebody he knows. We haven't been able to figure out whether that was a real apparition or only his imagination.