Behavioral Health Conditions & Illnesses View All Alcohol Abuse and Dependence Alcohol abuse means having unhealthy or dangerous drinking habits, such as drinking every day or drinking too much at a time. Bipolar Disorder Bipolar disorder is an illness that causes extreme mood changes from manic episodes of very high energy to the extreme lows of depression. Borderline Personality Disorder Borderline personality disorder is a mental illness that causes intense mood swings, impulsive behaviors, and severe problems with relationships and self-worth. Depression Depression is an illness that causes a person to feel sad and hopeless much of the time. It is different from normal feelings of sadness, grief, or low energy. Drug Abuse and Dependence Drug abuse is using drugs in a way that harms you or that leads you to harm others. Abuse can occur with illegal drugs, prescription drugs, or over-the-counter drugs. Generalized Anxiety Disorder Generalized anxiety disorder occurs when you feel worried and stressed about many everyday events and activities. Often the things you are worried about are small or not important. Obsessive-Compulsive Disorder Obsessive-compulsive disorder (OCD) is a type of mental illness that causes repeated unwanted thoughts. To get rid of the thoughts, a person does the same tasks over and over. Panic Attacks and Panic Disorder A panic attack is a sudden, intense fear or anxiety that may make you short of breath or dizzy or make your heart pound. You may feel out of control. Some people believe they are having a heart attack or are about to die. Post-Traumatic Stress Disorder Post-traumatic stress disorder (PTSD) can occur after you have been through a traumatic event. Scizophrenia Schizophrenia is a severe brain disease that interferes with normal brain and mental function—it can trigger hallucinations, delusions, paranoia, and significant lack of motivation. Social Anxiety Disorder People with social anxiety disorder (or social phobia) are extremely anxious about what they will say or do in front of other people.