Biological Causes of Generalized Anxiety Disorder

Biology and genetics can influence the development of GAD

Woman in bathroom tearing her hair out. Credit: Sven Hagolan

There are some biological causes of generalized anxiety disorder (GAD). In fact, research is producing a range of interesting findings on how our genes can influence our psychological makeup from personality quirks to development of mental disorders such as GAD.

What is Generalized Anxiety Disorder?

Many people feel anxious from time to time, especially during times of stress. However, when you worry excessively, so much so that it interferes with day-to-day activities, you might have GAD.

Some people develop GAD as a child while others do not see symptoms until they are an adult. Either way, living with GAD can last a long time. In many cases, it occurs along with other anxiety or mood disorders. In most cases, it improves with medications or talk therapy (psychotherapy). Making lifestyle changes, learning coping skills and using relaxation techniques also can help.

Symptoms of Generalized Anxiety Disorder

GAD symptoms can include:

  • Persistent worrying or obsession about small or large concerns that's out of proportion to the impact of the event
  • Inability to set aside or let go of a worry
  • Inability to relax, restlessness, and feeling keyed up or on edge
  • Difficulty concentrating, or the feeling that your mind "goes blank"
  • Worrying about excessively worrying
  • Distress about making decisions for fear of making the wrong decision
  • Carrying every option in a situation all the way out to its possible negative conclusion
  • Difficulty handling uncertainty or indecisiveness

Physical signs and symptoms may include:

  • Fatigue
  • Irritability
  • Muscle tension or muscle aches
  • Trembling, feeling twitchy
  • Being easily startled
  • Trouble sleeping
  • Sweating
  • Nausea, diarrhea or irritable bowel syndrome
  • Headaches

The following is a brief overview on some of the ways biology and genetics can influence the development of GAD.

Genetics and GAD

As a clinician, when someone comes to my office with some symptoms of GAD (such as excessive worry or constant anxiety), I immediately try to gather information about family members that may also have anxiety disorders or GAD. Almost without fail, someone (parent, grandparent, sibling) has some experience with significant anxiety as well. If not, often it is because the person simply does not have the information. This link is not just anecdotal: Researchers have shown a strong link for anxiety disorders in families and have been working hard to understand the underlying genes that create this life experience.

Brain Chemistry and GAD

Some parts of our brain chemistry are also involved in GAD. Most notably, the brains of people with GAD have abnormal levels of serotonin and norepinephrine. The most popular treatments for GAD work to correct this. It is unclear whether genes, some sort of environmental stress or another factor cause these levels to be different. But it is the source of ongoing research.


Mayo Clinic. Generalized Anxiety Disorder.

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