Gaslighting is a form of psychological abuse. It involves an increasing frequency of systematically withholing factual information from, and/or providing false information to the subject, having the gradual effect of making the victim anxious, confused, and less able to trust his or her own memory and perception. A variation of gaslighting, used as a form of harassment, is to subtly alter aspects of a victim's environment, thereby upsetting his or her peace of mind, sense of security, etc.