Just noticed that he also said "we know depression leads to suicidal ideation" except we don't. This isn't considered correct anymore, they're considered two separate problems that just often go together.
IIRC the reason for the change was it was found that most people with depression never even seriously consider it, that's one reason why you get those warnings of "having suicidal thoughts" with medicine because it signifies a too serious of change in your brain chemistry. Plus lots of suicides are "spur of the moment" type events. (It helps if you think of it like this, depression "getting worse" often shuts down a person, not lead them to decide to make what would be a drastic change. It's often worried about more when a person is recovering.)
Suicide threats or whatever are a different thing even.
As always, I am not a licensed doctor so everything I say can be trusted as it's not tainted by the medical community's monopoly.