20/02/2026
The 5 Most Common Mental Disorders
Mental health disorders, sometimes referred to as mental illnesses, affect the thoughts, moods and behaviors of those impacted. Although there is no clear link between genetics and the likelihood of having a mental health disorder, lifestyle factors such as diet, substance abuse and an individual’s activity can influence the onset of depression, anxiety and other conditions.
Mental health disorders may be occasional or chronic. And they affect an individual’s ability to relate to others and function day to day. While there are some steps to improve overall mental health, some disorders are more serious and may require professional intervention, temporarily or long term.
Below are the five most common mental health disorders in America and their related symptoms. This list of mental disorders is not all-inclusive; there are many that are not discussed below that may require additional mental disorder test options to find a treatment plan. In general, always consult with a mental health professional if you think you may have a mental disorder.
Anxiety Disorders
The most common category of mental health disorders in America—anxiety disorders—impacts approximately 40 million adults 18 and older. Anxiety disorders cause people to experience distressing and frequent fear and apprehension. While many may experience these feelings during a job interview or public speaking event (as that can be a normal response to stress), those with anxiety disorders feel them commonly and in typically non-stressful events. And bouts of anxiety can last up to six months or more at a time. “Anxiety” is actually a blanket term that includes a host of specific disorders, including the following: 👇
Mental health disorders, sometimes referred to as mental illnesses, affect the thoughts, moods and behaviors of those impacted.