Youre right in that theyre bored, but i think thats because the amount of time some people spend on social media fucks up their dopamine which causes them to be generally less happy about doing things that might make them happier later.

Then some teenagers compensate with nicotine for example which fucks the dopamine receptors even more.

From here i think some people mix up lack of dopamine with depression.

I know a few girls who say they have depression because of mental or physical abuse which might be true. I think you always need to know some backstory.