Association between thyroid hormone T3 and aggression in drug-naïve schizophrenia: a directed acyclic graph analysis

Area of Science:

• Neuroendocrinology
• Psychiatry
• Causal Inference

Background:

• Aggression is a significant clinical challenge in schizophrenia, with its biological underpinnings not fully understood.
• Investigating the role of thyroid hormones in aggression is crucial for understanding schizophrenia pathophysiology.

Purpose of the Study:

• To examine the relationship between thyroid hormones, psychiatric symptoms, and aggression in drug-naïve schizophrenia (DNS) patients.
• To utilize causal inference methods to elucidate these complex associations.

Main Methods:

• A case-control study involving 161 DNS patients and 63 healthy controls.
• Assessment of aggression using the Modified Overt Aggression Scale (MOAS) and psychiatric symptoms via the Positive and Negative Syndrome Scale (PANSS).
• Measurement of serum thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4), followed by causal inference analyses (DAG modeling, regression, mediation).

Main Results:

• Drug-naïve schizophrenia patients displayed significantly lower TSH levels compared to controls.
• Higher T3 levels and more severe positive symptoms were observed in the high-aggression group within the schizophrenia cohort.
• Causal analysis revealed a direct association between T3 levels and aggression severity, independent of other thyroid hormones and psychiatric symptoms.

Conclusions:

• Elevated triiodothyronine (T3) levels are directly associated with increased aggression severity in schizophrenia patients.
• Thyroid hormone dysregulation, particularly T3, may play a direct role in the manifestation of aggression in schizophrenia.