It's definitely a "civilizational disease" - a widespread condition that has deteriorating effect on mental health and happiness, noticeable at scale, caused by... the structure and pressures of modern living in urbanized, developed countries. It's also not something most individuals can "just fix" on their own through lifestyle intervention.

Yes. Loneliness is associated with extremely negative health outcomes comparable to physical disease, and some countries like the UK have gone as far as creating a dedicated minister to tackle the issue.

https://www.gov.uk/government/news/loneliness-minister-its-m...

Apart from the other answers, I want to add that there is a significant difference between loneliness and solitude. Loneliness is when you're alone but don't want to be. Solitude is when you're alone but perfectly content with it - you may even seek it.

As humans are social creatures, loneliness tends to arise when meaningful social interactions are consistently insufficient and you feel excluded from any relevant peer groups (family & friends mostly). This, of course, is a subjective matter.

I like this answer. You explained it in a way I could comprehend.

Thank you internet stranger.