Lipid profiles in schizophrenia associated with clinical traits: a five year follow-up study

Background: Alterations in serum and membrane lipids may be involved in schizophrenia pathophysiology. It is not known whether lipid profiles are associated with disease severity or current symptom level. Methods: Clinical and lipid data were gathered from 55 patients with schizophrenia admitted to psychiatric emergency wards in an acute stage of the disease (T-1). The patients were re-examined after 5 years at a stable phase (T-2). The clinical assessments included Positive and Negative Syndrome Scale (PANSS total, positive, negative) and Global Assessment of Functioning (GAF S, symptom and F, function). Serum lipids (cholesterol and triglyceride) and membrane polyunsaturated fatty acids (PUFA, LCPUFA) were measured. Healthy controls were recruited among hospital workers. Results: Serum triglyceride was significantly higher in patients with schizophrenia compared to healthy controls both at T-1 and T-2 (p < 0.001), while serum cholesterol did not differ significantly. The levels of serum lipids in patients remained stable over time. At T-1, serum lipids and symptoms were not significantly correlated. At T-2, higher serum lipids were associated with more severe symptoms and poorer functioning. Higher serum lipid levels at T-1 were associated with more severe symptoms and poorer functioning at T-2; cholesterol with GAF-S (p < 0.05), triglyceride with PANSS total (p < 0.05), GAF-S (p < 0.01) and GAF-F (p < 0.01). Membrane lipids were significantly lower in the patient group compared to healthy controls at T-1 (PUFA p < 0.001, LCPUFA p < 0.001), but not at T-2. Membrane lipids were not significantly correlated with symptoms at T-1, but significantly associated with negative symptoms and functioning at T-2 as previously reported. Conclusions: The present findings suggest different roles of membrane and serum lipids in schizophrenia pathophysiology. To further elucidate the relation of lipid biology to disease traits, replication in independent studies of longitudinal samples are warranted.