Anxiety is a normal biological reaction. We all experience it at one time or another, whether it's before giving a presentation at the office, while boarding an airplane or hearing the phone ring in the middle of the night.

“Anxiety an emotional response to a perceived future threat or danger," says L. Kevin Chapman, a clinical psychologist in Louisville, Kentucky, who specializes in anxiety disorders and cognitive behavioral therapy, or CBT. These responses include cognitive thoughts about the perceived threat, such as uncontrollability or unpredictability of the event; physical feelings, such as a racing heart, shortness of breath, tension or hot or cold flashes; and behaviors, including escape or avoidance, says Chapman.

Normal anxiety is occasional, controllable and finite. Chronic or uncontrollable anxiety, however, it not normal. "When anxiety becomes exaggerated and starts impairing functioning in one or more aspects of life, it may take the form of an anxiety disorder,” says Dr. Richa Bhatia, a psychiatrist and former faculty member at Harvard Medical School and the Geisel School of Medicine at Dartmouth College. Both biological and environmental factors may cause anxiety disorders. Having an immediate family member with an anxiety disorder, for example, increases the likelihood of developing the disorder. But environmental factors may also lead to anxiety disorders. These can include experiencing adverse or stressful life events or childhood trauma.

But what you ingest can also contribute to your anxiety.

Be Wary of Caffeine, Nicotine and Alcohol

Excessive or high intake of caffeine has been shown by studies to increase risk of anxiety, especially panic attacks, particularly in sensitive individuals such as those already suffering from psychiatric conditions, and in adolescents and others who are genetically predisposed,” says Bhatia, who is a member of the professional education committee of the Anxiety and Depression Association of America.

Both caffeine and tobacco can contribute to the manifestation of anxiety in different ways, particularly by contributing to the physiological arousal associated with anxiety. Just think of a time you had one cup of coffee too many.

"Caffeine acts as a stimulant and mimics the physical symptoms associated with anxiety, such as heart palpitations, restlessness, chest tightness, hot flushes and other symptoms," Chapman says. Bhatia adds that substances like caffeine may biologically influence anxiety by their action on certain receptors and neurotransmitters in the brain. "Caffeine acts in the brain via various mechanisms. Some of these mechanisms have been implicated in triggering, exacerbating or maintaining anxiety. Caffeine can influence the neuroendocrine stress response system via its effects on the hypothalamic-pituitary-adrenal axis and stress hormone in the body," she explains. In other words, this means that caffeine can trigger one of the biomechanisms that leads to the production of the stress hormone cortisol, which activates the flight-or-fight response that causes anxiety-like symptoms.

Interestingly, tobacco and alcohol typically provide temporary anxiety relief to the user, Chapman says, but they subsequently backfire and contribute to both maintaining and worsening anxiety symptoms. "Both alcohol and tobacco appear to have paradoxical effects on the user as it relates to anxiety," he says. Initially, smoking provides an initial relief due to interacting with nicotine receptors and providing a bit of a "stress relief." However, prolonged smoking contributes to long-term symptoms of anxiety, particularly during withdrawal from the substance.

Similarly, alcohol is a depressant and can provide a calming, sedative effect to the body when consumed. "However, prolonged consumption of alcohol, even in moderation, backfires and contributes to the maintenance and worsening of anxiety, partially due to the withdrawal symptoms that mimic anxiety," Chapman says. She adds that anxiety disorders often occur along with substance use disorders, and there is a bidirectional relationship among these disorders. "Many individuals use substances as a form of self-medication from negative emotional experiences, though the substances contribute to the same negative emotional experiences," he says.

User Beware

Certain prescription and over-the-counter medications, including corticosteroids for asthma and allergies or pain and headache relievers that contain caffeine, may also exacerbate anxiety symptoms. "Additionally, substances such as cocaine, marijuana and hallucinogens can undoubtedly contribute to symptoms of anxiety," Chapman says.

Every individual is different and will experience different effects from these substances. "Genetic predisposition, sensitivity due to developing brain in adolescence and the presence of other psychiatric conditions are some of the factors that may determine susceptibility," Bhatia says.