Borderline personality disorder (BPD) is a psychiatric disorder that involves such personality-related problems as diminished self-awareness, unpredictable moods and a marked tendency toward impulsive behavior. As is true with other personality disorders, mental health professionals generally avoid diagnosing BPD in teenagers and younger children because people in these age groups are still going through important phases of mental development. However, according to the results of a study published in 2011 by researchers from the University of Houston, teenagers who later receive a BPD diagnosis as adults consistently develop a precursor to the disorder that manifests as an inability to accurately \u201cmentalize,\u201d or interpret the thoughts and intentions of others. What Are Personality Disorders? Mental health professionals use the term personality disorder to refer to any established pattern of thought or behavior that restricts the emotional\/social perspective of the affected individual and significantly diminishes his or her ability to interact appropriately with others on an interpersonal, social, school-related or work-related level. Some people with these disorders recognize their role in the disconnection between themselves and others whereas others blame other people for the difficulties they encounter. The specific symptoms of these disorders vary substantially, but all personality disorders produce general symptoms such as volatile emotional states, a lack of stable relationships, varying degrees of social isolation and poor self-control. As stated previously, teens and younger children are still developing key aspects of their personality, and therefore don\u2019t typically receive a personality disorder diagnosis, even if they have symptoms that would merit such a diagnosis in an adult. Borderline Personality Disorder The \u201cborderline\u201d in borderline personality disorder refers to a now-outdated belief among mental health professionals that people with the condition had symptoms that sat on the diagnostic border between neurotic behavior (also now largely viewed as an outdated concept) and psychotic behavior. Because this belief is no longer held, experts in the field commonly use the abbreviation for the disorder, BPD, in order to minimize confusion. People with BPD have symptoms that include emotional volatility, poor impulse control, and a lack of insight into their own behaviors. Additional symptoms of the disorder include a fear of loneliness and a pattern of unstable relationships. People affected by BPD may also engage in a variety of self-harming behaviors, up to and including suicide attempts. What Is Mentalization? Mentalization is a term that psychologists use to describe the ability to understand one\u2019s own mental state well enough to properly interpret the mental states of others. In a sense, this ability is a function of the imagination, since it involves \u201cmaking up\u201d things about other people and using those made up things to navigate social interactions. People who mentalize accurately can properly interpret the intentions of others and use this interpretation to predict how a given individual will act in a given set of circumstances. People who mentalize inaccurately fail to properly interpret the intentions of others, and therefore lack at least some of the ability to predict the actions of others. Hypermentalization as a BPD Precursor in Teens In a two-year study published in 2011 in the Journal of the American Academy of Child & Adolescent Psychiatry, a team of researchers from the University of Houston examined the mentalization abilities of 111 hospitalized children between the ages of 12 and 17. With the help of self-reports from the study participants and a tool known as the Movie for the Assessment of Cognition, the researchers placed each child into one of four different mentalization categories: \u00a0accurately mentalizing, no mentalizing, less mentalizing, and overmentalizing or hypermentalizing. The researchers also assessed the study participants for symptoms of BPD and found that 23 percent of the children met the criteria that would trigger a BPD diagnosis in an adult. The authors of the study used the term hypermentalization to refer to a strong tendency to infer too much about a person\u2019s motivations or intentions from a limited amount of evidence or interaction. After reviewing the findings, they concluded that teens who meet the adult criteria for BPD hypermentalize more frequently than teens who don\u2019t meet the adult BPD criteria. They also concluded that the misreading of others caused by hypermentalization leads to medically significant amounts of emotional upset in affected teens and a subsequent increase in BPD-related symptoms. Early Identification of BPD The University of Houston researchers believe that their findings point toward heightened levels of hypermentalization in teenagers as a consistent diagnostic precursor for the adult onset of BPD. They also believe that early identification of hypermentalization in teens can potentially lead to earlier detection of BPD-related tendencies and a quicker resolution of BPD symptoms.