A serious mental illness marked by unstable moods and impulsive behavior. People with BPD have problems with relationships, family and work life, long-term planning, and self-identity. Symptoms include intense bouts of anger, depression, and anxiety that may lead to self-injury or suicide, drug or alcohol abuse, excessive spending, binge eating, or risky sex. A person with BPD who is diagnosed with cancer may be at an increased risk of suicide. Also called BPD.