High-density lipoprotein (HDL) in older patients with schizophrenia: implications for clinical and cognitive outcomes.

BACKGROUND: This study investigated the role of high-density lipoprotein (HDL) in older patients with schizophrenia (SCZ), examining its associations with clinical symptoms, cognitive function, and other conventional lipid parameters (triglycerides, total cholesterol), as well as its longitudinal changes during a 6-month follow-up period under routine clinical care. METHODS: A total of 77 participants (30 healthy controls [HC] and 47 SCZ patients) were stratified into high- and low-HDL subgroups based on a cutoff of 0.91 mmol/L. Baseline comparisons revealed significantly lower HDL levels in the SCZ group compared to HC. The SCZ group, as expected, exhibited significant psychopathology (assessed by PANSS) and impaired cognitive performance across multiple RBANS domains. RESULTS: HDL subgroup analysis demonstrated that among SCZ patients, the high-HDL subgroup exhibited higher PANSS scores and worse performance in specific delayed memory domains compared to the low-HDL subgroup. In SCZ patients, correlation analysis showed a positive association between HDL and PANSS scores (r = 0.28, p < 0.05) and a negative correlation with performance in one delayed memory task (Figure Recall: r = -0.30, p = 0.04). Longitudinal follow-up after 6 months in the SCZ group revealed a reduction in HDL levels (though not statistically significant), along with decreased PANSS scores and improved RBANS total scores. CONCLUSION: These findings reveal a complex relationship between HDL and SCZ. While SCZ patients have lower HDL than healthy controls, within the patient group, higher HDL levels were paradoxically associated with greater symptom severity and poorer memory performance. This suggests that in older patients with chronic SCZ, the functional quality of HDL may be more critical than its absolute concentration.