Efficacy and safety of supraphysiologic doses of levothyroxine for patients with bipolar depression in adults: A systematic review

Hypokalemic Hypophosphatemic Thyrotoxic Periodic Paralysis Associated with Bipolar Disorder Therapy

Hypokalemic thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism. TPP occurs due to the intracellular shift of potassium in the setting of elevated thyroid hormone. As potassium begins to be replenished, there is a risk of inducing hyperkalemia due to the extracellular shift of potassium. Therefore, it is recommended to replete potassium conservatively. There have been a number of studies reviewing the possible benefits of elevated thyroid hormone in treating bipolar disorder. In this case report, a 37-year-old man with a past medical history of hypothyroidism and bipolar disorder presented with bilateral lower extremity paralysis. Liothyronine was added to his stable hypothyroid regimen for bipolar management. His initial labs on presentation were notable for severe hypokalemia, hypophosphatemia, and an undetectable thyroid-stimulating hormone (TSH). He was diagnosed with TPP, and his electrolytes were corrected with minimal repletion within 24 hours. More research is still required before concluding the role of thyroid hormone in mood disorders. This case report demonstrates a serious complication of supplemental thyroid hormone use. It is crucial to monitor thyroid function tests closely in order to avoid iatrogenic hyperthyroidism.

Clinical symptoms, thyroid dysfunction, and metabolic disturbances in first-episode drug-naïve major depressive disorder patients with suicide attempts: A network perspective

BACKGROUNDS

Co-occurrence of thyroid dysfunction, metabolic disturbances, and worsening clinical symptoms in major depressive disorder (MDD) patients with suicidal attempts (SA) are common. However, their relationship in SA patients remains unexplored. We aimed to (1) determine the independent association of thyroid dysfunction, clinical symptoms, and metabolic disturbances with SA; and (2) identify their interactions in SA patients via the network approach.

METHODS

1718 FEDN MDD patients were recruited. Depressive, anxiety, and psychotic symptoms were assessed by the Hamilton Rating Scale for Depression (HAMD), the Hamilton Rating Scale for Anxiety (HAMA), and the Positive and Negative Syndrome Subscale positive subscale, respectively. The serum levels of thyroid hormones and other metabolic parameters were assessed. Logistic regression model was applied to determine the correlates of SA. Network analysis was applied to determine the interaction between thyroid dysfunction, clinical symptoms, and metabolic disturbances.

RESULTS

SA patients had significant worse metabolic disturbances, thyroid dysfunction, and clinical symptoms than non-SA patients. Thyroid peroxidases antibody, thyroid stimulating hormone (TSH), HAMD scores, HAMA scores, and systolic blood pressure was independently associated with SA. Network analysis suggested that TSH was the hub of the network, exhibiting substantial associations with metabolic disturbances, anxiety, and psychotic symptoms in SA patients.

CONCLUSIONS

Our work highlights the predominant role of serum TSH levels in the pathophysiology of SA. Regular thyroid function tests might help early detect SA. Targeting increased TSH levels may help reduce metabolic disturbances and clinical symptoms in SA patients.

Thyroid Hormone Augmentation for Bipolar Disorder: A Systematic Review

Thyroid hormone (TH) augmentation, although commonly used for major depression, is sparingly used for bipolar disorder (BD) after the failure of mood-stabilizing agents. While the exact mechanisms of thyroid hormone action in BD remains unclear, central thyroid hormone deficit has been postulated as a mechanism for rapid cycling. This systematic review-conducted in accordance with the PRISMA guidelines-of eight studies synthesizes the evidence for TH augmentation in BD. A systematic search of the Ovid MEDLINE, Embase, PsycINFO, and Cochrane databases was conducted for randomized controlled trials (RCT), open-label trials, and observational studies of levothyroxine (LT4) and triiodothyronine (T3) for BD. Open-label studies of high dose LT4 augmentation for bipolar depression and rapid cycling showed improvement in depression outcomes and reduction in recurrence, respectively. However, an RCT of high-dose LT4 did not show benefit in contrast to placebo. An RCT comparing LT4, T3, and placebo showed benefit only in rapid-cycling bipolar women. A meta-analysis could not be completed due to significant differences in study designs, interventions, and outcomes. Our systematic review shows mixed evidence and a lack of high-quality studies. The initial promise of supratherapeutic LT4 augmentation from open-label trials has not been consistently replicated in RCTs. Limited data are available for T3. The studies did not report significant thyrotoxicosis, and TH augmentation were well tolerated. Therefore, TH augmentation, especially with supratherapeutic doses, should be reserved for highly treatment-resistant bipolar depression and rapid-cycling BD.