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 once enjoyed. It can lead to a variety of emotional and physical problems and can decrease your ability to function at work and at home.

Stress is a normal reaction to the pressures of everyday life. Worry, fear, anger, sadness and other emotions are also all normal emotional responses. They are all part of life. However, if the stress that underlies these emotions interferes with your ability to do the things you want or need to do, this stress has become unhealthy.

What is panic disorder? Panic disorder occurs when you experience recurring unexpected panic attacks. The DSM-5 defines panic attacks as abrupt surges of intense fear or discomfort that peak within minutes. People with the disorder live in fear of having a panic attack.

Bipolar disorder, also known as manic depression, is a mental illness that brings severe high and low moods and changes in sleep, energy, thinking, and behavior. People who have bipolar disorder can have periods in which they feel overly happy and energized and other periods of feeling very sad, hopeless, and sluggish.

Schizophrenia is a serious mental disorder in which people interpret reality abnormally. Schizophrenia may result in some combination of hallucinations, delusions, and extremely disordered thinking and behavior that impairs daily functioning, and can be disabling.