text: High-T3 syndrome in thyroid carcinoma may result from autonomous thyroid hormone secretion or overexpression of type 2 deiodinase in cancer cells rather than from type 2 allostasis.
  Conditions with mixed phenotypes
  Psychiatry
  Stress suppresses TSH, and alterations in thyroid hormone levels may arise  in psychiatric illness. In major depressive disorder, an NTIS-like phenotype may be observed, with reduced T3 and increased rT3. T4 may be elevated, and TSH is usually normal, although TSH's normal circadian rhythm may be disrupted. Bipolar 1 and PTSD can exemplify an anti-NTIS phenotype, with upregulation of the HPT axis and increased T3. This may also occur during acute schizophrenic episodes.
  Exercise
  After exercise, a transient increase occurs in TSH, T4, and T3, but this is thought to be due to increased blood concentration as a result of dehydration. The effects normalize after rest. After long-term heavy strain, levels of thyroid hormones decrease. This is exacerbated by other stressors such as undernutrition and lack of sleep, such as in a military training setting. During endurance exercise, before exhaustion, elevated thyroid hormone levels may happen due to increased expected energy demand (type 2 allostatic load).
  Environmental conditions
  Cold exposure and stay at high altitude may lead to type 1 or type 2 phenotype, depending on duration and other boundary conditions (which determine whether or not stress is associated with energy deprivation).