Preliminary evidence that a functional polymorphism in type 1 deiodinase is associated with enhanced potentiation of the antidepressant effect of sertraline by triiodothyronine.

BACKGROUND: Triiodothyronine (T3) is used to potentiate the clinical effect of antidepressant drugs. Inter-individual differences in efficacy may be related to genetically-based variability in thyroid function. METHODS: DNA was obtained from 64 patients treated with sertraline plus T3 (SERT-T3, N=35) or plus placebo (SERT-PLB, N=29), for 8 weeks. Antidepressant efficacy was rated with the 21 item Hamilton Rating Scale for Depression (HRSD-21). Functional polymorphisms in type 1 (DIO1-C785T, DIO1-A1814G) and type 2 deiodinase (DIO2-Thr92Ala and DIO2-ORFa-Gly3Asp) were genotyped. RESULTS: DIO1-C785T was associated with efficacy of T3 but not placebo supplementation, as indicated by the interaction of treatment, DIO1-C758T genotype and time (p=0.04) and a stronger effect of SERT-T3 among DIO1-758T allele carriers (p=0.01). HRSD-21 scores of DIO1-758T allele carriers declined by 68.7+26.6% (mean+SD) over 8 weeks compared to 42.9+37.8% among non-carriers (p=0.02). DISCUSSION: DIO1 plays a key-role in T4 to T3 conversion and in clearance of the inactive metabolite, rT3. Previous data associate the DIO1-785T allele with lower DIO1 activity. This is consistent with our observation that responders to T3 supplementation had lower baseline serum T3 levels than non-responders. Depressed patients, who have a genetically determined lower T4 to T3 conversion, may be more likely to benefit from T3 supplementation.

Combined treatment with sertraline and liothyronine in major depression: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Antidepressant treatments that achieve a higher remission rate than those currently available are urgently needed. The thyroid hormone triiodothyronine may potentiate antidepressant effects. OBJECTIVE: To determine the antidepressant efficacy and safety of liothyronine sodium (triiodothyronine) when administered concurrently with the selective serotonin reuptake inhibitor sertraline hydrochloride to patients with major depressive disorder. DESIGN: Double-blind, randomized, 8-week, placebo-controlled trial. SETTING: Outpatient referral centers. PATIENTS: A total of 124 adult outpatients meeting unmodified DSM-IV criteria for major depressive disorder without psychotic features. INTERVENTIONS: Patients were randomized to receive sertraline hydrochloride (50 mg/d for 1 week; 100 mg/d thereafter) plus liothyronine sodium (20-25 microg/d for 1 week; 40-50 microg/d thereafter) or sertraline plus placebo for 8 weeks. MAIN OUTCOME MEASURES: The primary outcome measure was categorical response to treatment (> or =50% decrease in scores on the 21-item Hamilton Rating Scale for Depression from baseline to study end point). Remission rate (final Hamilton Rating Scale for Depression score, < or =6) was a secondary outcome measure. RESULTS: Intent-to-treat Hamilton Rating Scale for Depression response rates were 70% and 50% in the sertraline-liothyronine and sertraline-placebo groups, respectively (P = .02; odds ratio, 2.93; 95% confidence interval, 1.23-7.35); remission rates were 58% with sertraline-liothyronine and 38% with sertraline-placebo (P = .02; odds ratio, 2.69; 95% confidence interval, 1.16-6.49). Baseline T(3) values were lower in patients treated with sertraline-liothyronine who had remissions than in those without remissions (t(48) = 3.36; P<.002). Among patients treated with sertraline-liothyronine, remission was associated with a significant decrease in serum thyrotropin values (F(1,73) = 4.00; P<.05). There were no significant effects of liothyronine supplementation on frequency of adverse effects. CONCLUSIONS: These results demonstrate enhancement of the antidepressant effect of sertraline by concurrent treatment with liothyronine without a significant increase in adverse effects. The antidepressant effect of liothyronine may be directly linked to thyroid function.