Is fatigue a common symptom of anxiety?

Fatigue as a Symptom of Anxiety

Yes, fatigue is a common symptom of anxiety, occurring as part of the emotional distress cluster that frequently accompanies anxiety disorders. 1

Relationship Between Anxiety and Fatigue

Anxiety and fatigue often co-occur as part of a symptom cluster that includes:

• Emotional distress (anxiety, depression)
• Sleep disturbance
• Pain
• Fatigue

Evidence Base

• Descriptive studies have consistently shown that fatigue seldom occurs alone but commonly clusters with sleep disturbance, emotional distress (including anxiety), and pain 1
• Research indicates a high prevalence of anxiety in patients with chronic fatigue, with one study showing 72.4% of chronic fatigue patients experiencing generalized worry 2
• Another study found that 41.9% of patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis experienced threshold levels of health anxiety 3
• Twin studies suggest that chronic fatigue and psychological distress (including anxiety) have a strong environmental association 4

Physiological Mechanisms

The relationship between anxiety and fatigue can be explained through several mechanisms:

1. Autonomic nervous system activation: Anxiety triggers a prolonged stress response with increased cortisol and adrenaline, eventually leading to adrenal fatigue
2. Sleep disruption: Anxiety commonly causes sleep disturbances, which directly contribute to daytime fatigue
3. Muscle tension: Chronic anxiety leads to persistent muscle tension, requiring increased energy expenditure
4. Cognitive load: Excessive worry and rumination consume mental energy, contributing to mental fatigue

Clinical Implications

When evaluating patients with fatigue:

• Always assess for concurrent anxiety symptoms, as they may be driving or exacerbating fatigue 1, 5
• Recognize that treating anxiety may significantly improve fatigue symptoms 2
• Consider that severe anxiety/worry is associated with greater overall fatigue scores and worse functional status 2

Treatment Considerations

When treating patients with both anxiety and fatigue:

• Cognitive-behavioral therapy has shown effectiveness for both anxiety and fatigue symptoms 2
• Medications for anxiety may help with fatigue, but be aware that some (like venlafaxine) list fatigue as a common side effect 6
• Duloxetine may cause fatigue in some patients, particularly those with chronic pain conditions 7
• Address sleep disturbances as part of the treatment plan, as they contribute to both anxiety and fatigue 1, 5

Common Pitfalls to Avoid

1. Attributing fatigue solely to physical causes without assessing for anxiety or other psychological factors
2. Treating only the fatigue without addressing underlying anxiety
3. Overlooking sleep disturbances that may be contributing to both anxiety and fatigue
4. Assuming fatigue in anxious patients is "just psychological" rather than recognizing the complex bidirectional relationship

Special Populations

• Cancer patients: Experience significantly higher levels of both fatigue and anxiety compared to non-cancer controls, with anxiety predicting fatigue intensity 8
• Postpartum women: State anxiety is a consistently strong predictor of fatigue intensity across time 9

Remember that addressing anxiety symptoms may significantly improve fatigue and overall quality of life in patients experiencing both conditions.