borderline(redirected from borderlines)
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1. of a phenomenon, straddling the dividing line between two categories.
2. a term used in psychiatry for personality disorders originally viewed as being on the border between psychosis and neurosis. See borderline personality disorder.
borderline personality disorder a personality disorder marked by various features of borderline personality organization, such as instability, impulsiveness, intense or poorly controlled anger, inability to tolerate being alone, and chronic feelings of emptiness. Affected individuals sometimes seem to be on the borderline of psychosis and are highly unstable in mood, behavior, self-image, and affect. None of the features of the condition are constant; behavior is highly unpredictable and such persons seldom achieve their full potential. Their interpersonal relationships are often stormy because of their shifts in attitude and their tendency to idealize, devalue, or manipulate others. Suicidal gestures and self-mutilation sometimes occur with this disorder. The American Psychiatric Association has published Practice Guidelines for the Treatment of Patients with Borderline Personality Disorder, which is printed on their web site at http://www.psych.org.
1. A line that establishes or marks a border.
2. An indefinite area intermediate between two qualities or conditions: The borderline between love and hate is often thin.
3. Informal A person with borderline personality disorder.
a. Verging on a given quality or condition: borderline poverty.
b. Of a questionable nature or quality: an applicant with borderline qualifications.
2. Psychiatry Of, related to, or having borderline personality disorder.