The psychological symptoms of GAD are chronic, exaggerated worry, restlessness, tension, and irritability, that appear to have no cause, or are more intense than is reasonable in the situation.

People with GAD may also have concentration problems and trouble going to sleep or staying asleep. In addition to these psychological symptoms there are often physical signs such as trembling, headaches, dizziness, twitching, muscle tension, aches or soreness, abdominal upsets, and sweating.

Most of those with GAD claim to have felt anxious for their entire lives, and the disorder is often first seen in childhood or adolescence. However, adult onset of the disorder is not uncommon.

Experts believe that GAD is probably caused by a combination of biological factors and life events. Many people who have GAD also have other medical disorders, such as depression and/or panic disorder, that seem to involve changes in brain chemistry, in particular abnormalities in the levels of the neurotransmitter serotonin.