I admit I haven't read the article but lately it's been popular to link mental illness to pretty common things. Poor sleep? The logic kinda makes sense. Not sleeping at all will 100% drive you insane, so it could make sense that sleeping only half what you should will have some effect.

But its much more likely that some people genetically and family-wisw are just more suceptible than others. Trying to find an external cause is probably futile.