Send to

Choose Destination
Thyroid. 2007 Mar;17(3):249-58.

Health status, psychological symptoms, mood, and cognition in L-thyroxine-treated hypothyroid subjects.

Author information

Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon, USA.



Many hypothyroid subjects receiving L-thyroxine (L-T4) complain of psychological symptoms or cognitive dysfunction. However, there is limited validated information on these self-reports.


Cross-sectional comparison of 20 euthyroid and 34 treated hypothyroid subjects, aged 20-45 years, with normal thyroid-stimulating hormone (TSH) levels. Subjects underwent the following validated measures: Short Form 36 (SF-36); Symptom Checklist 90-Revised (SCL-90-R); Profile of Mood States (POMS); and tests of declarative memory (Paragraph Recall, Complex Figure), working memory (N-Back, Subject Ordered Pointing, Digit Span Backwards), and motor learning (Pursuit Rotor).


L-T4-treated subjects had higher mean TSH and free T4 levels, but free triiodothyronine (T3) levels were comparable to controls. L-T4-treated subjects had decrements on SF-36 and SCL-90-R summary scales and subscales. These subjects performed slightly worse on N-Back and Pursuit Rotor tests. Neither TSH nor thyroid hormone levels were associated with performance on psychological or cognitive measures.


This group of L-T4-treated subjects had decrements in health status, psychological function, working memory, and motor learning compared to euthyroid controls. Higher mean TSH levels suggest this may be related to suboptimal treatment, although there were no correlations between TSH levels and outcomes. These findings are limited by potential selection bias, and randomized studies targeting different TSH levels and memory subdomains would clarify these issues.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center