Gender differences in thyroid system function: relevance to bipolar disorder and its treatment.
OBJECTIVE
Thyroid hormones play a critical role in the functioning of the adult brain, and thyroid diseases impair both mood and cognition. This paper reviews gender differences in thyroid system function that are relevant to the diagnosis and treatment of bipolar disorder.


METHODS
The study comprised a comprehensive literature review of gender differences in thyroid disease that are pertinent to mood disorders.


RESULTS
The prevalence of thyroid disease was found to be much higher in females than males, and to increase with age. The most commonly detected abnormality was subclinical hypothyroidism, which was found to occur in up to 20% of postmenopausal women. Females also had higher rates of thyroid autoimmunity. Individuals at risk for thyroid disease, such as adult females, may have had less ability to compensate for additional challenges to thyroid metabolism, including lithium treatment. Thyroid abnormalities were associated with a poorer response to standard treatments for mood disorders. Females with treatment-resistant mood disorders may have responded better than males to adjunctive therapy with thyroid hormones.


CONCLUSIONS
Disturbances of thyroid system function, which occur commonly in females, may complicate the diagnosis and treatment of mood disorders. In particular, this is clinically relevant during lithium treatment because lithium may impair vital thyroid metabolic pathways secondary to its anti-thyroid activity.
Department of Psychiatry and Psychotherapy, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Michael
M
Bauer
Tasha
T
Glenn
Maximilian
M
Pilhatsch
Andrea
A
Pfennig
Peter C
PC
Whybrow
D001714:Bipolar Disorder / Q000175:diagnosis* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D012727:Sex Characteristics; D013961:Thyroid Gland / Q000502:physiology*
bipolar disorder; depression; gender differences; thyroid hormone; thyroid system