Denying mental illness as a coping mechanism

Do you think it's common for people who strongly deny depression or any other mental illness is a real thing could actually be trying to hide their own personal problems? I know there are some people who truly believe there is no such thing as mental illnesses while others will claim that all you have to do is snap out of it and you'll be fine. I've heard people say stuff like you're not actually depressed or just snap out of it and stop hurting yourself. Sometimes I think this is their own way of hiding their own troubles by acting tough and appearing to have their life under control.

Some people deny the existence of mental illnesses due to their upbringing while others choose to ignore facts backed by years of research claiming that anyone who is depressed is just hurting themselves. Some will go great lengths to do this while appearing to have problems of their own especially if they're generally a negative person which makes me think they're hiding something. It seems more likely someone is trying to hide their own problems by denying the existence of depression despite contradictory behaviors they're displaying. Unfortunately there are those who deny the existence of depression just because they think it's attention seeking behavior and that all you need to do is snap out of it even though it's not that easy.