The capture of souls

It isn't possible to steal someone's entire soul, but in some traditions, there is a belief in soul loss via thievery where a "piece" of the spirit attaches to the taker due to emotional attachment or "runs away", retreating to a place of safety due to trauma. No one looks kindly upon those who purposely take, and you're liable to meet serious aggression if another magick practitioner gets involved to retrieve the soul loss.

Soul loss symptoms can include nightmares and dreams of the "taker", depression, and PTSD symptoms.

In significant romantic relationships, soul loss can be mutual if the two have symbolically "given" apart of themselves to each other or pledged/promised such things sincerely like so many stupidly do. Especially if one is not desiring separation it can cause serious mental disturbances for both parties involved.

But the consciousness is a different "part" of the soul, commonly referred to as "the mind", and that ties deeply with the personality or identity and cannot be stolen.