A VICIOUS CYCLE OF LOW-SELF ESTEEM

Not so much concerning the bullied, but more so concerning the one bullying.
Low self-esteem either brought on my one's own failings or by others is can be a possible catalyst to a practice of bullying.....Verbally either face to face, on the internet, bullying someone emotionally or physically bullying someone or others my reveal what the psychological make up of the person who bullys. What do you think?