Substance use disorder occurs when a person's use of alcohol or another substance (drug) leads to health issues or problems at work, school, or home. This disorder is also called substance abuse. Causes The exact cause of substance use disorder is not known. A...

Post-traumatic stress disorder can happen to a person after experiencing a traumatic event that has caused them to feel fearful, shocked, or helpless. It can have long-term effects, including flashbacks, difficulty sleeping, and anxiety. Examples of events that can...

A person with bipolar disorder will experience changes in mood, energy, and activity levels that can make day-to-day living difficult. Bipolar disorder can cause severe disruption to a person’s life, but the impact varies between individuals. With appropriate...

Anxiety is a normal and often healthy emotion. However, when a person regularly feels disproportionate levels of anxiety, it might become a medical disorder. Anxiety disorders form a category of mental health diagnoses that lead to excessive nervousness, fear,...

Depression (major depressive disorder) is a common and serious medical illness that negatively affects how you feel, the way you think and how you act. Fortunately, it is also treatable. Depression causes feelings of sadness and/or a loss of interest in activities you...