When should prolactin levels be checked in patients with chronic anxiety?

Prolactin Testing in Patients with Chronic Anxiety

Prolactin levels should be checked in patients with chronic anxiety only when they present with specific symptoms suggestive of hyperprolactinemia, such as menstrual disturbances, galactorrhea, visual field changes, or symptoms of hypogonadism, or when they are taking medications known to elevate prolactin levels. 1

When to Check Prolactin in Anxiety Patients

Anxiety alone is not an indication for prolactin testing. The Endocrine Society recommends prolactin measurement in the following specific circumstances:

• Patients presenting with:

  • Menstrual disturbances
  • Galactorrhea
  • Visual field loss
  • Symptoms of hypogonadism (decreased libido, erectile dysfunction)
  • Infertility 1

• Medication review:

  • Patients taking antipsychotics or other medications known to cause hyperprolactinemia 1
  • Common medications that can elevate prolactin include typical and atypical antipsychotics, metoclopramide, and certain antidepressants

• Low testosterone with low/normal LH levels in male patients 1

Relationship Between Anxiety and Prolactin

While some research has suggested a potential relationship between hyperprolactinemia and psychological symptoms:

• 56.2% of hyperprolactinemic patients showed anxiety symptoms compared to 32.2% of controls in one study 2
• Patients with "functional" hyperprolactinemia (normal CT scans) showed more psychological distress than those with definite pituitary microadenomas 3

However, these findings do not support routine prolactin testing in all anxiety patients, as the relationship appears bidirectional - anxiety can cause transient prolactin elevation, and hyperprolactinemia may contribute to psychological symptoms in some patients.

Avoiding Diagnostic Pitfalls

When testing prolactin in appropriate cases, be aware of:

• Stress-induced elevation: Venipuncture stress can transiently elevate prolactin levels 4

  • Consider serial measurements under resting conditions if stress-related hyperprolactinemia is suspected
  • 20 out of 70 women with elevated prolactin in multiple random samples were found to have stress-related hyperprolactinemia 4

• Rule out other causes before specialized testing: 5

  • Pregnancy
  • Drug-induced hyperprolactinemia
  • Primary hypothyroidism
  • Renal failure

• Interpret levels appropriately: 5

  • PRL >250 ng/mL: Highly suggestive of prolactinomas
  • PRL <100 ng/mL: More common in drug-induced hyperprolactinemia, macroprolactinemia, or systemic diseases
  • Consider "hook effect" in large pituitary adenomas with normal or mildly elevated prolactin

Clinical Approach to Suspected Hyperprolactinemia

1. Evaluate for specific symptoms suggesting hyperprolactinemia
2. Review medications that could cause elevated prolactin
3. If indicated, measure serum prolactin (preferably morning fasting sample)
4. If elevated, rule out physiological causes (pregnancy, stress) and other medical conditions (hypothyroidism, renal failure)
5. Consider macroprolactin screening for unexplained elevations
6. Refer to endocrinology for prolactin levels >25 ng/mL without obvious cause

Treatment Considerations

If hyperprolactinemia is confirmed in an anxiety patient:

• Cabergoline is the preferred first-line treatment for prolactinomas 1
• Start with lower doses and titrate slowly if side effects occur
• Monitor both prolactin levels and tumor size regularly
• Consider cardiac monitoring with echocardiography for patients on higher doses 1

Remember that anxiety symptoms may improve with treatment of hyperprolactinemia in some patients, but dedicated anxiety treatment should continue as needed.