Mental illness is an equal-opportunity disabler that can be broken into two general categories for most people: mood and anxiety disorders. Mental illness can strike at any age, regardless of your gender, race or income level. It is not a result of personal weakness, lower intelligence, lack of character or poor upbringing. Mood and anxiety disorders are medical conditions that, fortunately, can be treated.

The causes of mental illness are varied and include long lists of genetic, chemical, environmental and psychological factors. Often, though, mental illness is the result of a combination of causes.

Mood Disorders
It’s perfectly normal to experience bouts of sadness, loneliness or moodiness. They are natural and healthy responses to traumatic events—such as the loss of a job or the death of a loved one—or other stressful situations, whether short-lived and traumatic or long-reaching and persistent. By comparison, mood disorders are serious, pervasive conditions that affect both the mind and the body.

Major depression is one of the most common mood disorders, affecting nearly 15 million American adults, or nearly 5 percent of the U.S. population. It affects all races, ethnicities and income levels. Not only is it a leading cause of disability in the United States among people ages 15 to 44, but it has also been linked to a number of other serious illnesses. Heart attacks, for example, are four times more likely to occur among those with major depression than those without a history of the mental illness.

More than the occasional blues, major depression is marked by periods of intense sadness, feelings of guilt and worthlessness, trouble concentrating, sleep and appetite problems and lack of interest in things a person usually finds enjoyable. To be diagnosed with major depression, a person must have several symptoms occurring on most days for at least two weeks.

Mild depression, technically known as dysthymia, affects another 3 million Americans. Whereas bouts of major depression can come and go, dysthymia is often chronic and unrelenting—sometimes for years.

Also under the umbrella of mood-related illnesses is bipolar disorder, affecting roughly 6 million Americans. It usually involves intense periods of excitability, or mania, followed by periods of major depression. Manic episodes, lasting days or sometimes months, can include risk-taking activities, increased energy and activity, euphoria and paranoia. The depressive episodes that frequently follow can include many or all of the symptoms seen in major depression.

There is also seasonal affective disorder, or SAD. As its name suggests, this mood disorder is generally associated with increased symptoms of depression during the winter months, when there is less natural light to stimulate the central nervous system.

Anxiety Disorders
Anxiety may not be pleasant, but it’s typically a healthy response to life’s stresses. However, when anxiety becomes excessive—manifested in unusually strong and persistent feelings of fear and dread—it can become a disabling disorder.

Generalized anxiety disorder (GAD) is the most common form of anxiety disorder among adults, affecting nearly 7 million Americans. It is marked by persistent worry and anxiety about everyday activities. In some people, GAD is fairly mild and does not interfere with daily living. In others, the condition can be severe and interfere with work, school and family as well as social responsibilities.

People with panic disorder often experience symptoms associated with GAD, along with panic attacks—feelings of being overwhelmed with terror. About 6 million Americans suffer from panic disorder, nearly a third of whom will go on to develop a phobia in efforts to avoid stressors, such as the agoraphobe who never leaves the house in order to avoid public places.

Unhealthy anxiety can also manifest as recurrent negative thoughts (obsessions) and repetitive behaviors (compulsions). Combined, they can lead to obsessive-compulsive disorder (OCD). Compulsions such as ritualized and incessant counting, cleaning and hand washing are often performed to prevent or reverse obsessive thoughts that can lead to panic attacks. It’s estimated that more than 2 million Americans struggle with OCD.

Finally there is post-traumatic stress disorder (PTSD), a debilitating compilation of anxiety-related symptoms, including persistent frightening thoughts and panic. It affects nearly 8 million people in the United States. Typically thought of as a lingering psychological effect of war or physically violent acts, PTSD can follow any traumatic or extremely stressful event.