Reasons: False beliefs around lack, insecurity, unworthiness, learnt helplessness. Leading to adopting of a victim mindset, lack of generosity, excessive focus on oneself, and fear of missing out.
The void or emptiness is there in everyone, and it only gets filled by engaging with the world productively at some level, whether it’s through relationships, social contributions, job, or any other means. Even refining yourself spiritually is an act of being of service to the world.
Unfortunately some of us have been dealt a tough hand and have not learnt the ways of how to engage productivity with the world, resulting a painfully acute experience of emptiness that can push us towards addictions. The solution is to be understanding and loving towards oneself, and then do the hard work of learning to engage productively with word. The hard work may seem unfair, but it is our challenge, and it has to be met by us.