>True, but the thought is that the feelings of worthlessness, hopelessness, even suicide are seratonin related.

Not necessarily true. People on SSRIs can still want to commit suicide after serotonin rebounds and is at a stable level.

I think complex feelings like despair and self-hatred can't be explained by just a single neurotransmitter. Serotonin likely plays a role here, but it's not the only component.