Outcomes of Self-help Efforts in Anxiety Disorders

Amy J Morgan; Anthony F Jorm


Expert Rev Pharmacoeconomics Outcomes Res. 2009;9(5):445-459. 

In This Article

Dietary Changes

Caffeine Reduction

Description Caffeine is a CNS stimulant that can be found in coffee, tea, cola and chocolate.

Therapeutic Mechanism It is thought that caffeine can induce anxiety by binding to adenosine receptors and blocking the anxiolytic effects of adenosine. Furthermore, caffeine intoxication presents with similar symptoms to anxiety (e.g., restlessness and nervousness) and some anxiety disorders may be caffeine-induced.[1] Hence, for these reasons, reducing or abstaining from caffeine could be helpful for those with anxiety disorders.

Review of Efficacy A previous review found six RCTs where caffeine was administered to patients with panic disorder, generalized anxiety disorder or social phobia after a caffeine-free period (caffeine challenge). There was a consistent short-term increase in anxiety following caffeine administration compared with placebo.[15] However there was no evidence from trials evaluating caffeine reduction or abstention in patients with anxiety disorders. Since this review, another RCT has replicated the increase in anxiety from caffeine challenge in patients with panic disorder and depression with panic attacks.[49] However, there are no long-term studies of caffeine consumption or studies of caffeine reduction or abstention in patients with anxiety disorders.

Safety Issues Symptoms of caffeine withdrawal include headache, fatigue, decreased energy/activeness, decreased alertness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability and foggy/not clearheaded. These symptoms may last for 2–9 days.[50]

Conclusion There is some evidence that caffeine consumption leads to increased anxiety levels in the short-term in individuals with anxiety disorders; however, there is no evidence from controlled trials in anxiety disorders of the effect of reducing or eliminating caffeine consumption.

Foods Rich in Tryptophan

Description Some claim that eating foods rich in tryptophan, an amino acid, may be helpful for anxiety.

Therapeutic Mechanism When tryptophan is in the CNS, it gets transformed into serotonin, which aids in the treatment of anxiety. It is thought that when foods rich in tryptophan are consumed along with a high glycemic index carbohydrate, tryptophan levels are raised in the CNS because the release of insulin caused by the carbohydrate reduces competing amino acids from crossing the blood–brain barrier.

Review of Efficacy One small pilot study has evaluated deoiled pumpkin seed (a rich source of tryptophan) as a treatment for social phobia.[51] The study was a double-blind, placebo-controlled, crossover study with a wash-out period of 1 week between experimental sessions. Seven participants were randomly assigned to start with either deoiled pumpkin seed in combination with carbohydrate, or carbohydrate alone, and exposed to an anxiety-producing stimulus. The gourd seed and carbohydrate combination, but not carbohydrate alone, resulted in significant improvement on one out of two objective measures of anxiety, but the effects on a subjective measure of anxiety did not reach statistical significance.

Safety Issues No safety issues are currently known.

Conclusion One small study has indicated a potential effect of deoiled pumpkin seed on social anxiety, but the study needs to be replicated with a larger sample before firm conclusions can be made.


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