Ygtjki

I've long felt that some people engage in unskillful behaviour as a consequence of not valuing themselves. For example, they engage in drugs to numb or detrimental sexuality, seemingly because they feel unworthy or undeserving.

Would Buddhism link such a behaviour to self-compassion or self-esteem? Is there such a thing in Buddhism as instincts of self-harm?

Or, even, can such self-impeding behaviour be linked to some other cause, such as not seeing the consequence of actions or something of the like?

Thank you

The origin of detrimental behavior is the "self" itself. Because self is ultimately an illusion and doesn't exists, and people's belief and identification to self makes them trapped in the cycle of suffering. The "self" can never feel worthy, because it is an illusion and an illusion is always incomplete and insecure. That's why the people who have deep narcissistic personality disorder always need to cause trouble for themselves and others because their identity is always based on the "self", which means their identity is always based on an illusion. Also the identification of the self always makes people have lack of awareness and most of the people are acting their conditioning from their birth to death. So most people literally don't know what they are doing and they are completely under control of the thoughts, emotions and feelings.

The only way to become free from this never-ending cycle is to become free from the self itself. Trying to build a self esteem can temporarily work but it would collapse sooner or later because a sand castle can't live that long. A person who becomes free from the belief of the self and completely becomes free from the identification from it would have great peace and contentment and would not identified with the thoughts, emotions and feelings again so it would be impossible for him/her to act as an ordinary egotistical person again.

That being said, denying the identification with the self is not beneficial either because untill a person completely becomes free from identification with the self-which happens in the once-returner stage-the identification with the self would continue for a person. So even that the self is ultimately an illusion, the nature of being a human is being identified to this illusion. That's why Buddhism gives the humanity the roadmap to become free from this illusion. And the core of this roadmap is mindfulness and staying away from the unwholesome actions.

These are beings who are suffering from passion / greed (raga) and delusion (moha). If they are denied their object of passion, they will suffer from aversion (dosa).

The following sutta quote shows how unenlightened beings who indulge in sensual pleasures, burn with sensual fever, and try to indulge in it even more. It's an addiction.

A person who is continuously suffering from delusion (moha) will not be able to see the consequences of their actions. Delusion intensifies passion / greed or aversion, and clouds one's mind and judgment. For e.g. it converts anger to rage, or converts sexual attraction to becoming overcome with sexual lust.

From MN 75:

"In the same way, Magandiya, sensual pleasures in the past were
painful to the touch, very hot & scorching; sensual pleasures in the
future will be painful to the touch, very hot & scorching; sensual
pleasures at present are painful to the touch, very hot & scorching;
but when beings are not free from passion for sensual pleasures —
devoured by sensual craving, burning with sensual fever — their
faculties are impaired, which is why, even though sensual pleasures
are actually painful to the touch, they have the skewed perception of
'pleasant.'

"Now suppose that there was a leper covered with sores & infections,
devoured by worms, picking the scabs off the openings of his wounds
with his nails, cauterizing his body over a pit of glowing embers. The
more he cauterized his body over the pit of glowing embers, the more
disgusting, foul-smelling, & putrid the openings of his wounds would
become, and yet he would feel a modicum of enjoyment & satisfaction
because of the itchiness of his wounds. In the same way, beings not
free from passion for sensual pleasures — devoured by sensual craving,
burning with sensual fever — indulge in sensual pleasures. The more
they indulge in sensual pleasures, the more their sensual craving
increases and the more they burn with sensual fever, and yet they feel
a modicum of enjoyment & satisfaction dependent on the five strings of
sensuality.