Regardless of context, silent treatment is a form of emotional abuse.
Whether this is occurring in a friendship, a professional setting or a personal relationship, such treatment is considered abuse since in essence silence is being used to acquire control of a situation. Silent treatment triggers mental and emotional conflicts that go unresolved with time because most of the time the behavior cannot be justified other than the abuser 'trying to teach another person a lesson' or overcoming a power struggle. Some forms of silent treatment are the following: ignoring a person's phone calls "knowing" that the lack of response will irritate the caller, ignoring a person's presence "knowing" the one ignored will take notice, sharing common space with an individual and avoiding conversation or interaction at all cost, performing actions in front of an individual "knowing" that it will emotionally make them vulnerable and etc. Short and long term effects of silent treatment abuse can maim one's self esteem, confidence and outlook on life. If you know anyone that is suffering such treatment, encourage the subject to seek treatment because no type of abuse is acceptable or justifiable in life. Please seek out a confidante or a counselor who may be able to assist you. Remember-people are either part of the problem or part of the solution. Choose wisely.