Checking TSH in Binge Eating Disorder
While the 2023 APA guidelines for eating disorders do not specifically mandate TSH testing for binge eating disorder, checking TSH is clinically important to rule out thyroid dysfunction as a medical mimicker or contributor to disordered eating behaviors, and to identify potential thyroid hormone misuse for weight manipulation.
Why TSH Testing Matters
Differential Diagnosis and Medical Screening
The 2023 APA guidelines recommend that initial evaluation of patients with eating disorders include a comprehensive review of systems and identification of co-occurring health conditions 1. However, the specific laboratory recommendations focus on CBC and comprehensive metabolic panel (electrolytes, liver enzymes, renal function) 1, without explicitly mentioning thyroid function tests.
The clinical rationale for TSH testing in binge eating disorder includes:
Thyroid dysfunction can mimic or exacerbate eating disorder symptoms: Hypothyroidism causes weight gain, fatigue, and mood changes that may contribute to binge eating behaviors. Hyperthyroidism can cause increased appetite and metabolic changes.
Higher prevalence of thyroid disease in eating disorders: Research shows that female patients with eating disorders and depression have a 53% incidence of thyroid disease compared to 17% in those with depression alone 2. This is substantially higher than the general population prevalence of 10.5% 2.
Detection of Thyroid Hormone Misuse
A critical but often overlooked reason for TSH testing is to identify thyroid hormone misuse for weight control. Recent data shows that 10.6% of individuals with eating disorders are taking thyroid hormone replacement 3—a frequency significantly greater than expected from epidemiologic studies of thyroid disease prevalence.
Those taking thyroid hormones show:
- Greater frequency of low serum TSH 3
- Abnormal free thyroxine levels 3
- Suggesting excessive hormone doses used for weight manipulation 3
The 2023 APA guidelines specifically note that evaluation should assess "use of medication to manipulate weight" 1, and thyroid hormone is a common agent for this purpose.
Metabolic Health Monitoring
While binge eating disorder patients typically have normal baseline thyroid function, they warrant monitoring because:
- Women with BED show larger increases in TSH over time compared to other eating disorders 4
- Chaotic eating patterns can affect thyroid hormone levels 5, 6
- Treatment non-responders show more unfavorable metabolic responses at follow-up 4
Clinical Algorithm
At initial evaluation:
- Order TSH (with reflex to free T4 if abnormal)
- Specifically ask about thyroid medication use, including over-the-counter supplements
- If patient is on thyroid hormone, determine indication and prescriber
- Review for symptoms of hypo/hyperthyroidism that overlap with eating disorder presentation
If TSH is abnormal or patient is on thyroid hormone:
- Low TSH: Consider hyperthyroidism, excessive thyroid hormone replacement, or intentional misuse
- High TSH: Consider hypothyroidism as contributor to weight concerns and eating behaviors
- On thyroid hormone without clear indication: This represents a treatment intervention opportunity 3
Key Pitfalls to Avoid
- Don't assume normal thyroid function without testing: The prevalence of thyroid disease is doubled in eating disorder populations 2
- Don't overlook thyroid hormone as a weight manipulation tool: Direct questioning about all medications used for weight control is essential
- Don't dismiss borderline abnormal results: Even subclinical thyroid dysfunction may contribute to eating disorder psychopathology and metabolic complications
The absence of explicit TSH testing in the APA laboratory recommendations likely reflects that binge eating disorder patients are generally less medically compromised than those with restrictive eating disorders. However, the comprehensive review of systems and co-occurring conditions mandate 1 provides the framework for including thyroid assessment as part of thorough medical evaluation.