Anxiety can arise suddenly, as in panic, or gradually over minutes, hours, or days.

Anxiety can last for any length of time, from a few seconds to years.

It ranges in intensity from barely noticeable qualms to a full-blown panic attack, which may cause shortness of breath, dizziness, an increased heart rate, and trembling (tremor).

Anxiety disorders can be so distressing and interfere so much with an individual’s life that they can lead to depression.

Individuals may develop a substance use disorder.

Individuals who have an anxiety disorder (except for certain very specific phobias, such as fear of spiders) are at least twice as likely to have depression as those without an anxiety disorder.

Sometimes individuals with depression develop an anxiety disorder.