For the collection of the presented reports the PubMed database was searched using key terms such as “psychiatric disease,” “schizophrenia,” and “thyroid hormones [levels],” and/or designation of each thyroid hormone specifically [total and free thyroxine (TT4 and FT4) and triiodothyronine (TT3 and FT3), and thyroid stimulating hormone (TSH)]. This evidence concerns the gene TG and schizophrenia.