Seasonal Variations

   Patients with many psychiatric conditions -- including schizophrenia, schizoaffective disorder, major depression, bipolar disorder and autism --have a seasonal birth distribution (Torrey et al, 1997; Ticher et al, 1996).

   Thyroid hormone seasonal patterns have been identified (i.e. Reed 1995; Hall 1999). As the subjects age, have a fixed thyroid hormone dosage for hypothyroidism, or spend an extended number of months in polar conditions, a reflex TSH rise occurs.

(This makes people living in such conditions even more susceptible to F-poisoning)

==================================== =========

Hall SK, Hutchesson AC, Kirk JM - "Congenital hypothyroidism, seasonality and consanguinity in the West Midlands, England" Acta Paediatr 88(2):212-5 (1999) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=10102157&form=6&db=m&Dopt=r

Reed HL - "Circannual changes in thyroid hormone physiology: the role of cold environmental temperatures"  Arctic Med Res 54 Suppl 2:9-15 (1995) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=8900825&form=6&db=m&Dopt=r

Ticher A, Ring A, Barak Y, Elizur A, Weizman A - "Circannual pattern of
autistic births: reanalysis in three ethnic groups" Hum Biol 68(4):585-92(1996) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=8754264&form=6&db=m&Dopt=r

Torrey EF, Miller J, Rawlings R, Yolken RH - "Seasonality of births in
schizophrenia and bipolar disorder: a review of the literature (review)."
Schizophr Res 28(1):1-38 (1997) http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&uid=98089531&Dopt=r