Are bipolar disorder, major depression, and suicidality linked with Toxoplasma gondii? A seromolecular case-control study

ObjectiveThe existence of predisposing effects of latent Toxoplasma gondii (T. gondii) infection in bipolar disorder (BD), major depression (MD), and even suicide attempt (SA) has long been debatable. This conjecture remains unclear because there is a lack of evidence regarding how T. gondii manipulates the brain and behavior.MethodsWe investigated the influence of T. gondii infection on BD and MD patients with or without SA compared to age-, sex-, and province-matched healthy controls (HCs) concurrently with serology and molecular-based evaluations. We prospectively assessed 147 volunteers with BD, 161 with MD, and 310 HCs.ResultsT. gondii seropositivity rates were 57.1% for BD, 29.2% for MD, 64.8% for SA, and 21.3% for HC. Binary logistic regression analyses revealed that T. gondii positive Immunoglobulin G (IgG) status may be a prominent tendentious agent for BD (OR = 3.52; 95% CI [2.19-5.80]; p < 0.001) and SA (OR = 17.17; 95% CI [8.12-36.28]; p < 0.001), but not for MD (OR = 1.21; 95% CI [0.74-1.99]; p = 0.45). Nevertheless, the T. gondii DNA ratios determined by polymerase chain reaction (PCR) were linked to BD and MD.ConclusionOur findings strongly support the burgeoning interest in the possibility that latent T. gondii infection may be relevant to the etiology of BD and SA, although this connection remains ambiguous.

Automated summary

This study suggests that latent Toxoplasma gondii infection may be associated with bipolar disorder and suicide attempt, but not strongly linked to major depression. However, the level of Toxoplasma gondii DNA may be related to both bipolar disorder and major depression.