Intimate partner violence is a blanket term used to describe various forms of actual or implied violence that occur between people involved in physical relationships, or with a history of prior involvement. Experts and laypeople alike commonly refer to this form of conduct as domestic violence. In a study published in July 2013 in the Journal of Addictive Diseases, researchers from three U.S. institutions sought to determine whether people who take PCP (phencyclidine) commit acts of domestic violence more often than people who use cannabis (marijuana, hashish) or combine cannabis with alcohol. Intimate Partner Violence Basics Intimate partner violence may appear in forms that include physical violence, sexual violence, acts centered on the threat of using sexual or physical violence, and acts centered on the use of psychological violence. Physical intimate partner violence includes any purposeful employment of brute force to harm or control a spouse or domestic partner. Sexual intimate partner violence includes sexual abuse, sexual coercion or involvement of a non-consenting spouse or partner in a sexual act. A person threatening acts of physical or sexual violence may relay his or her threats through verbal or written statements, body language or the brandishing of weapons. Psychological intimate partner violence involves coercive, restrictive or threatening behaviors designed to control a person without direct physical or sexual confrontation. However, a pattern of physical or sexual violence is commonly established prior to the commission of acts of psychological violence. While men are sometimes the targets of violent domestic acts, women experience this type of violence at a far greater rate. PCP Basics Phencyclidine is an anesthetic that also has some of the mind-altering properties that characterize substances called hallucinogens. In the medical world, the idea of using PCP in humans has been effectively abandoned for 50 years, and veterinarians also stay away from the drug whenever possible. PCP produces its main effects by diminishing or severing the normal perceptual cues that keep a person psychologically anchored in his or her surroundings. This highly detached mental\/emotional state, known formally as dissociation, also sharply limits the ability to feel pain. Other effects commonly associated with use of the drug include anxiety, euphoria, time distortion, an inability to think clearly, an agitated or paranoid mental state, panic, delusional thinking and an increased level of hostility or aggression. When used in excessive amounts, PCP can trigger a dangerous (and potentially fatal) change in normal physical function called overdose. The disorientation and delusional thinking triggered by use of the drug can also contribute to fatal outcomes. Roughly 1.6 percent of U.S. high school seniors have used PCP at some point in time, the National Institute on Drug Abuse reports. The lifetime usage rate in all adults age 26 or older is 3 percent. Recent Findings PCP has a reputation for producing unusually violent behavior in its users. In the study published in the Journal of Addictive Diseases, researchers from Yale University, the State University of New York at Buffalo and the Rochester Institute of Technology tested this reputation both within and outside of the context of intimate partner violence. During the study, these researchers compared the violence histories of 109 PCP users to the violence histories of 81 cannabis users and 97 people who simultaneously used cannabis and alcohol. All of the participating individuals had previously established records of at least some involvement in intimate partner violence. After completing their comparisons, the researchers found several indications that PCP users perpetrate violence significantly more often than either cannabis users or combined cannabis\/alcohol users. Examples of these indications include higher rates of involvement in domestic violence in the year prior to the study, higher rates of involvement in other forms of violence in the year prior to the study, higher lifetime rates of legal action for violence-related offenses and higher chances of being referred by a medical professional for inpatient, violence-related treatment. Considerations Some experts believe that PCP use itself does not directly lead to an increase in violent behavior. Instead, they believe that use of the drug may only produce violent episodes in people already affected by serious, destabilizing mental health problems such as antisocial personality disorder or the severely disoriented state called psychosis. In addition, some of the behaviors in PCP users that seem violent from the outside may not actually be intended to cause harm to others.