ارتباط بین غلظت لیپیدهای سرم و پریشانی روانی

This study examines the correlations between serum lipid levels and psychological distress. There were 4444 consecutive attendees of general health clinics who participated in the study. Psychological symptoms were measured by the Taiwanese version of the Symptoms Check List 90, revised (T-SCL-90-R). Levels of fasting serum lipids, including total cholesterol, total triglycerides and high-density lipoprotein cholesterol (HDL-C), were determined. Multiple linear regression analyses, with adjustment for confounders, revealed that the concentration of HDL-C had significant inverse associations with scores of depression, somatization and phobic anxiety. Women with an HDL-C level lower than 35 mg/dl scored significantly higher on depression, interpersonal sensitivity, phobia, anxiety, somatization and aggressive hostility, while subjects with a total cholesterol concentration lower than 160 mg/dl scored significantly higher on anxiety, aggressive hostility, phobia, and psychoticism. This study provides, for the first time, comprehensive data derived from the Taiwanese population on the link between lipids and psychological symptoms, revealing a reverse correlation between depression and serum concentrations of HDL-C.

The serum levels of lipids, including triglycerides, total cholesterol and high-density lipoprotein cholesterol (HDL-C), have been reported to be significantly associated with a number of psychopathological conditions such as schizophrenia, depression, aggressive hostility, and suicide (Lindberg et al., 1992, Engelberg, 1992, Weidner et al., 1992, Morgan et al., 1993, Golier et al., 1995, Boston et al., 1996, Maes et al., 1997 and Steegmans et al., 2000). 1.1. Lipids and schizophrenia The association between serum lipid levels and schizophrenia has been investigated (Modai et al., 1994, Boston et al., 1996 and Walker et al., 1999). The increased rate of breakdown of phospholipids and the reduced rate of incorporation of highly unsaturated fatty acids (HUFAs) into phospholipids are two abnormalities related to phospholipid metabolism in schizophrenia (Horrobin, 1998 and Horrobin, 1999). Phospholipase A2 (PLA2) and fatty acid coenzyme A ligase-4 (FACLs-4) are two key enzymes involved in signal transduction processes following the activation of various receptors, including D2 and 5-HT2, which are involved in the pathophysiology and medical treatment of schizophrenia. Recent additional evidence showing that defective PLA2 and FACLs-4 result in the failure of the incorporation of HUFAs into cell signaling compartments and increased oxidation of HUFAs may explain the association between serum lipid levels and schizophrenia (Horrobin, 1998 and Horrobin, 1999). 1.2. Lipids and suicide and aggression A reduction in high serum cholesterol levels in middle-aged subjects by diet, drugs, or both, was associated with a decrease in the number of deaths from coronary heart disease (CHD), but with an increase in mortality due to suicide or violence (Lindberg et al., 1992). Some later studies showed a significant association between low serum cholesterol and suicide (Modai et al., 1994, Takei et al., 1994, Golier et al., 1995 and Gallerani et al., 1995), but others found that parasuicide patients had higher mean cholesterol levels than controls (Ryan and Murray, 1995). Boston et al. (1996) considered that differences in the subjects’ sociodemographic characteristics and cholesterol levels might explain the contradictory results. Neaton et al. (1992), in a larger sample study, reported that suicide risk increased with serum cholesterol levels lower than 160 mg/dl (4.14 mmol/l). Early studies showed an association between low cholesterol levels and the expression of aggressive and antisocial behavior in criminal populations (Virkkunen, 1979 and Virkkunen, 1983). Among homicidal offenders, lower cholesterol levels were found in those who were violent only when intoxicated by alcohol (Virkkunen, 1983). Hillbrand and colleagues found that hospitalized male forensic patients with low cholesterol levels (<5.2 mmol/l) engaged in more frequent aggression (Hillbrand and Foster, 1993 and Hillbrand et al., 1995). Fowkes et al. (1992) found no significant association between serum cholesterol levels and aggressive traits (hostile acts and domineering attitude) in men; however, these traits were associated with elevated triglyceride levels. 1.3. Lipids and depression The relationship between serum lipids and depression has been comprehensively studied. Morgan et al. (1993) reported a significantly negative association between plasma cholesterol and the depression symptom score. This association remained significant after adjustment for various confounding factors. Their data also showed that there was a three-fold higher incidence of common, categorically defined depression in the group with low plasma cholesterol compared to those with higher concentrations. Steegmans et al. (2000) found that middle-aged men with chronically low serum cholesterol levels had a consistently higher risk of having depressive symptoms. This trend remained significant after adjusting for age, energy intake, alcohol use, and the presence of chronic disease. Maes et al. (1997), in a case-controlled study, showed that total serum cholesterol and HDL-C levels, as well as the ratio of HDL-C to total cholesterol, were significantly lower in subjects with major depression compared with normal control subjects. Recently, two prospective studies showed that cholesterol-lowering dietary treatment did not impair cognitive function and psychological well-being (Muldoon et al., 2000 and Wardle et al., 2000). However, the reductions in cholesterol levels in these two studies were not as low as the level that increased the risk of having depression or suicide in the previous studies (<160 mg/dl or 4.14 mmol/l) (Engelberg, 1992 and Neaton et al., 1992). Low cholesterol levels have been widely considered to increase the risk of depression because of neuronal dysfunction resulting from changes in the microviscosity of cell membranes or signal transduction dysfunction (Golier et al., 1995 and Maes et al., 1994). Most of the previous clinical and epidemiological studies focused on single discrete psychiatric problems such as schizophrenia, depression, suicide, and antisocial personality disorder (Boston et al., 1996). There have been few studies investigating the relationship between serum lipids and various psychiatric disorders (Weidner et al., 1992). It is possible that low cholesterol levels could also be associated with various psychological symptoms apart from depression. In this study, we sought to examine the correlations between the levels of serum lipids, including cholesterol, triglycerides and HDL-C, and a number of psychological symptoms and levels of distress in a large sample of general health clinic attendees.