In a overly simplified way yes. It tends to be more the inability to have self confidence or lacking the natural ego to foster it healthily. So a over correction occurs.

With out treatment or outside help that results in problematic behavioural responses, and other issues.

So funny enough the lack of self esteem results in a facade of too much self esteem.

Again this is GROSSLY over simplifying it and doesn't even cover some of the more complex expressions of the topic.

Least this is how it's been explained to me by phycologists when we where helping my uncle deal with his narcissistic and bipolar disorders.

That man was a walking mine field of mental issues. Thankfully he's doing better now, only took 40+ years.