Low serum cholesterol is not associated with depression in the elderly: data from an Australian community study

The Relationships between Abnormal Serum Lipid Levels, Depression, and Suicidal Ideation According to Sex

(1) Background: Serum lipid levels affect not only nutritional status but also emotional state. The purpose of this study was to examine the effects of various socio-demographic characteristics, abnormal cholesterol levels, and BMI indicators on depressive symptoms and suicidal ideation in the Korean population. (2) Methods: A total of 23,692 people were surveyed using data from the Korea National Health and Nutrition Examination Survey (KNHNES) 2014, 2016, and 2018. Data from 11,653 patients were analyzed. Age, sex, chronic disease, smoking, alcohol consumption, total cholesterol (HDL, triglycerides), BMI, depression, and suicidal ideation were measured. (3) Results: According to sex, low HDL, high triglycerides, and suicidal ideation were significant, along with low education level, smoking, binge drinking, and high BMI. High triglyceride level was shown to significantly increase the risk of depression in males (OR = 1.535, 95% CI = 1.098–2.147). Factors affecting suicidal ideation in males were age, binge drinking, and depression, while blood lipid factors were not significant. (4) Conclusions: Of the types of serum lipid factors affecting depression and suicidal ideation, high triglycerides were found to be a risk factor for depression in men. Serum lipids can be used as biomarkers to reflect depressive symptoms in men depending on cholesterol level.

Comparison of blood lipid profile/thyroid function markers between unipolar and bipolar depressed patients and in depressed patients with anhedonia or suicidal thoughts

Background

This study aimed to investigate the differences in the serum levels of glucose, lipid, and thyroid function markers between unipolar and bipolar depressed patients, as well as the effect of anhedonia and suicidal thoughts on the levels of these biochemical parameters.

Methods

A total of 287 unmedicated depressed patients from January 2016 to December 2017 were included in this study, including 92 bipolar depressions and 195 unipolar depressions. Anhedonia was determined using the item 32 of Symptom Checklist (SCL-90). Suicide ideation was assessed by item 15 of SCL-90.

Results

The bipolar group had significantly lower lipid levels (including triglycerides, cholesterol, low-density lipoprotein cholesterol [LDL], very low-density lipoprotein cholesterol [VLDL]) and insulin resistance index but higher levels of prolactin, low triiodothyronine (T3) and free T3 (FT3) as well as higher incidence of anhedonia as compared with the unipolar group. Depressed patients with anhedonia had significantly higher LDL level than those without anhedonia. Depressed patients with suicidal thoughts had cholesterol and high-density lipoprotein cholesterol (HDL) level. The above-mentioned differences were confirmed by logistic regression analysis. Receiver operating characteristic curve (ROC) analysis showed that the area under the ROC curve (AUC) ranged from 0.546 to 0.685.

Conclusion

Triglycerides, cholesterol, LDL, VLDL T3, FT3 levels were significantly different between unipolar and bipolar depressed patients, which might have the potential to be the markers for differential diagnosis. Patients with anhedonia had lower LDL level, while patients with suicidal thoughts had higher levels of cholesterol and HDL as compared with the corresponding control groups.

The association between diet and mood: A systematic review of current literature

A number of studies have examined the association between diet and mood state, but the findings have been inconclusive. Herein, we conducted a systematic review to assess the association between different diet and mood state. PubMed, Cochrane's library, Science direct, Scopus, Google scholar and ISI web of science databases were searched for all available literature until December 2017 for studies assessing the association between diet and mood state. The Newcastle-Ottawa Scale and Jadad scale for reporting randomized clinical trials were used to assess study quality. A total of 18 studies out of 2857 met our inclusion criteria and included in our systematic review. Although there are not consistent findings between studies, it seems that DASH, vegetable-based, glycemic load-based, ketogenic and Paleo diets could improve mood more than the others. Further studies are needed to assess such relationship in a longer period to draw a firm link between diet and mood.

Serum lipid levels in depression and suicidality: The Korea National Health and Nutrition Examination Survey (KNHANES) 2014

BACKGROUND

The level of serum lipids has been reported to be associated with depression and suicidality, but the exact relationship between these factors remains controversial. The aim of this study was to investigate the association between lipid levels and depression with suicidality in large sample.

METHODS

We examined the association between serum lipid levels and the existence of mild depression measured using Patient Health Questionnaire 9 (PHQ-9) in a national sample of Korean. The data of 2055 men and 2894 women who participated in the 6th Korea National Health and Nutrition Examination Survey (KNHNES VI) were used. The serum concentration of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride, and total cholesterol were dichotomized and complex samples logistic regression was employed in the analysis.

RESULTS

There was a significant association between high level of HDL-C (≥40mg/dl) and depression in adult men, and between high level of triglyceride (≥150mg/dl) and depression in adult women. In middle-aged adults 45-64 year), increased level of depression and suicidality was related to high level of triglyceride, respectively. (depression, OR=2.20 (95% CI 1.26-3.85); suicidality, OR=3.66 (95% CI 1.41-9.51). Furthermore, we found that the increased number of abnormal lipids level was significantly associated with the increased prevalence of depression in women (OR =1.34, 95% CI =1.12-1.60) and in middle-aged adults (OR=1.43, 95% CI =1.12-1.82).

LIMITATIONS

As this study had a cross-sectional design, it was hard to investigate causation between lipid levels and depression, and the assessment of suicidality needs more validation.

CONCLUSION

Our findings support a significant association between the high level of HDL-C, triglyceride and depression in large sample data. Triglyceride was highly associated with suicidality in younger and middle-aged adults, but not in elderly adults. Further assessment could delineate relationship between serum lipid levels and depression with suicidality in other ethnic groups.

Dyslipidemia as a Potential Moderator of the Association between Hearing Loss and Depressive Symptoms

OBJECTIVES

Knowledge about moderation of the association between hearing loss and depression is scant. We investigated dyslipidemia as a potential moderator of the association between hearing/hearing loss and depressive symptoms.

DESIGN

Cross-sectional study.

SETTING

General population-based cohort in France (SU.VI.MAX 2; 2007-2009).

PARTICIPANTS

N= 4,307 adults (mean age = 61.5 ± 6.1 y; 59.6% women).

MEASUREMENTS

A score ≥ 16 on the Center for Epidemiologic Studies Depression Scale defined presence of depressive symptoms. Mean hearing level for each ear was defined as the pure-tone average of the following thresholds: 0.5, 1.0, 2.0 and 4.0 kHz; the value for the better hearing ear was retained for analysis. Hearing loss was defined as inability to hear at thresholds ≥ 25 dB in both ears. A subjective measure of perceived hearing loss was also used. Serum triglyceride, total-, LDL- and HDL-cholesterol concentrations were assessed in fasting blood samples and established cutoffs were used in multivariable logistic regression models. The interaction between hearing/hearing loss (independent variables) and each of the four lipid parameters was tested.

RESULTS

Even though the interaction tests regarding LDL-, HDL- cholesterol, and triglyceride status were statistically significant, the subgroup analyses revealed few significant and somewhat unexpected findings. In fact, among individuals with low LDL-cholesterol, unlike their counterparts with high LDL-cholesterol, there was an inverse association between hearing level in the better hearing ear and depressive symptoms (OR= 0.94; 95% CI: 0.89-0.99). Regarding the subjective measure of hearing, a few of the dyslipidemia-moderated associations were statistically significant, albeit not all in the predicted direction.

CONCLUSIONS

The findings provide some support for moderation of the association between hearing/hearing loss and depressive symptoms by dyslipidemia, with important lipid-specific and hearing measure-specific differences. The results could serve as impetus for future investigations in order to identify and target population subgroups with increased vulnerability to depression in the context of both sensory disability and aging.

Low cholesterol is associated with depression among US household population

OBJECTIVE

Serum cholesterol was reported to be associated with depressed mood, but the studies conducted among household population are rare.

METHODS

We used the data of 4115 men and 4275 women aged 18 or older, who completed a depression screening interview and had blood collected as a part of the National Health and Nutrition Examination Survey, 2005-2008. The serum concentrations of total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were gender-specifically categorized into lower, intermediate, and upper quartiles. Depression was measured using the Patient Health Questionnaire, a 9-item screening instrument asking about the frequency of depression symptoms over the past 2 weeks.

RESULTS

After adjustment for socio-demographics and behavioral risks, a U-shaped association was detected between severe depression and LDL-C among men. The odds ratios (ORs) of severe depression were 5.13 (95% CI=1.74-15.09), 1 (reference) and 2.28 (1.07-4.86) respectively for the men with lower (<169 mg/dL), intermediate (169-221 mg/dL), and upper quartile (≥ 222 mg/dL) LDL-C. Among women, lower HDL-C was significantly associated with an elevated odds of severe depression [OR=2.96 (1.59-5.52)] compared with upper quartile of HDL-C, the association diminished after adjustment for covariates [OR=1.24 (0.66-2.32)]. No clear pattern of association between cholesterol and moderate depression was observed from either men or women.

LIMITATION

The inherent limitation of cross-sectional design prevented the authors from investigating causality.

CONCLUSIONS

A U-shaped association was identified between LDL-C and severe depression among men. Further studies are necessary to explore the biological mechanism and identify the clinical implication among populations vulnerable to psychiatric disorders.

Ghrelin, paraoxonase and arylesterase levels in depressive patients before and after citalopram treatment

OBJECTIVES

The purpose of this study was to examine alterations in lipid profiles and in the serum concentrations of acylated and desacylated ghrelin, paraoxonase and arylesterase in psychiatric patients before and after treatment with 40 mg citalopram daily for 3 months.

DESIGN AND METHODS

Samples were collected from 22 healthy controls and 24 psychiatric patients before and after citalopram treatment. Blood levels of acylated and desacylated ghrelin were measured by radioimmunoassay. Paraoxonase and arylesterase activities were determined spectrophotometrically. Lipid parameters were measured on the OLYMPUS-AU400.

RESULTS

It was found that the levels of acylated, desacylated ghrelin, paraoxonase arylesterase, total cholesterol and triglyceride were lower in depressive patients before citalopram treatment than in the control group. Those parameters were not restored after citalopram treatment except for the arylesterase level.

CONCLUSION

Decreased PON1 and ghrelin levels as well as fluctuations in lipid profiles may be involved in the etiology of depressive disorders.

ApoE4 allele is associated with late-life depression: a population-based study

OBJECTIVE

This study aimed to clarify the relationship between the epsilon4 allele and late-life depression, taking into account lipid profile, vascular diseases, and sociodemographics.

METHODS

Using a multilevel stratified random sampling strategy, a total of 500 subjects aged 65 to 74 years were recruited for this cross-sectional study from the official household records of an entire county in southern Taiwan. Depressive symptoms were assessed by the Taiwanese Depression Questionnaire (TDQ). Cognitive function was assessed by the Short Portable Mental Status Questionnaire. Blood samples were collected for the determination of the apolipoprotein E (ApoE) polymorphism and the lipid profile.

RESULTS

A total of 283 subjects (58.7% male, with a mean age of 69.2 +/- 2.7 years) completed all questionnaires and collection of blood samples. Using the chi(2) test, the overall difference for frequency of the presence of the epsilon4 allele was significant among the severe group (TDQ score >18), moderate group (TDQ score 9-18), and mild group (TDQ score <9). The proportion of history of heart disease was significantly higher in the severe group than in the mild or moderate group. Kruskal-Wallis statistics revealed that the mean total and low-density lipoprotein cholesterol levels were significantly higher in the severe group than in the moderate or mild group. With our two-level four-class latent class regression model, the presence of the epsilon4 allele was significantly associated with the severely depressed group as compared to the nondepressed group, adjusting for vascular diseases and lipid profile.

CONCLUSION

The ApoE epsilon4 allele may be correlated with severe depression in the elderly through ways other than the "vascular depression" hypothesis.

Serum lipid levels in seasonal affective disorder

Previous research has assessed the relationship between blood lipid levels and depression with contradictory results. Several studies have linked low cholesterol levels with impulsive, aggressive and suicidal behaviours. The aim of this pilot study was to examine serum lipids in a sample of patients suffering from seasonal affective disorder (SAD). We conducted a retrospective analysis of data on total serum cholesterol and serum triglycerides in 39 SAD patients and 40 non-seasonally depressed or schizophrenic control subjects. Study subjects had to be free of psychotropic drugs for at least 2 weeks. Analysis of covariance (ANCOVA) was performed to assess group differences. After adjustment for significant covariates SAD patients had significantly lower total cholesterol levels (5.21 +/- 1.14 mmol/l) than control subjects (5.94 +/- 1.11 mmol/l; p = 0.013). Moreover, hypercholesterolemia (total cholesterol > 5.20 mmol/l) was significantly less frequent in the SAD group (46.2%) than in the control group (75.0%; p = 0.012). Total serum triglycerides did not differ significantly between SAD patients (1.54 +/- 1.07 mmol/l) and controls (1.56 +/- 0.96 mmol/l; p = 0.126). The results of this study support the idea that low cholesterol levels may be of pathogenetic importance in SAD. Further study in larger clinical samples is warranted to clarify our findings.

Cerebrovascular risk factors, vascular disease, and neuropsychological outcomes in adults with major depression

OBJECTIVE

To investigate the relationship of cerebrovascular risk factors (CVRFs), endothelial function, carotid artery intima medial thickness (IMT), and neuropsychological performance in a sample of 198 middle-aged and older individuals with major depressive disorder (MDD). Neuropsychological deficits are common among adults with MDD, particularly among those with CVRFs and potentially persons with subclinical vascular disease.

METHODS

CVRFs were indexed by the Framingham Stroke Risk Profile (FSRP) and serum cholesterol levels obtained by medical history and physical examination. Patients completed a neuropsychological test battery including measures of executive functioning, working memory, and verbal recall. Vascular function was indexed by carotid artery IMT and brachial artery flow mediated dilation (FMD). Hierarchical multiple regression analyses were used to investigate the association between CVRFs, vascular disease, and neurocognitive performance.

RESULTS

Greater FSRP scores were associated with poorer executive functioning (b = -0.86; p = .041) and working memory (b = -0.90; p = .024). Lower high-density lipoprotein levels also were associated with poorer executive functioning (b = 1.03; p = .035). Higher IMT (b = -0.83; p = .028) and lower FMD (b = 1.29; p = .032) were associated with poorer executive functioning after controlling for CVRFs. Lower FMD was also associated with poorer working memory (b = 1.58; p = .015).

CONCLUSIONS

Greater CVRFs were associated with poorer neuropsychological performance. Vascular dysfunction also was associated with neuropsychological decrements independent of traditional CVRFs.

Relationship between major depression and high serum cholesterol in Japanese men

Although it has been argued that those with lower levels of serum cholesterol are likely to be depressive, the findings are inconsistent. The present study attempted to clarify the relationship between major depression and serum total cholesterol in a working population. Subjects were 987 Japanese men working at an institute, aged 20 to 64 years. In addition to blood examinations and physical measurements, clinical structured interviews of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) were used to detect major depression. The prevalence of major depression was higher in the hypercholesterolemics (serum total cholesterol levels > or = 5.69 mmol/liter) than in the normocholesterolemics (3.10-5.69 mmol/liter) (6.1% vs 1.8%, p < 0.05). Notably, there was no case with major depression among the hypocholesterolemics (< 3.10 mmol/liter). Through a multiple regression analysis, serum total cholesterol levels were positively predicted by the following four variables: major depression, age, body mass index, and skipping breakfast (all p < 0.01). Concerning those diagnosed with major depression, serum total cholesterol levels remained higher in the following year (p < 0.05), comparing to those without such diagnosis. Therefore, depression is associated with higher serum cholesterol levels in a population of Japanese male workers. The irregularity of eating behavior may be one of the factors mediating high serum cholesterol levels and major depression.

Vascular disease/risk and late-life depression in a Korean community population

BACKGROUND

Associations between vascular risk factors and late-life depression are controversial.

AIMS

To investigate the association between measures of vascular disease/risk and depression and confounding and effect modification by APOE genotype and cognitive function.

METHOD

In a Korean community population aged 65+ (n=732), diagnosis of depression (Geriatric Mental State Schedule) and information on vascular status, disability, APOE genotype and cognitive function were obtained.

RESULTS

Previous stroke and lower high-density lipoprotein cholesterol level (but neither hypertension nor diabetes) were significantly associated with depression (independently of disability and cognitive function). These associations were stronger in participants with borderline cognitive impairment, although not to a significant extent.

CONCLUSIONS

Except for previous stroke and an atherogenic lipid profile, associations between depression and other common risk factors for cerebrovascular disease were not evident.

Lipid and lipoprotein levels in depressive disorders with melancholic feature or atypical feature and dysthymia

The purpose of the present study was to explore the relationship between serum lipid and lipoprotein levels and clinical subtypes in patients with depressive disorders. A total of 207 patients who were admitted for general health screening were assessed by using the semistructured clinical interview for Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) criteria for the possibility of having depressive disorders. Blood and physical examinations were done to rule out systemic diseases. A total of 142 patients without systemic diseases was recruited for further analysis, including dysthymia (n = 35), major depressive disorder with melancholic feature (n = 22), major depressive disorder with atypical feature (n = 46) and normal controls (n = 39). Analysis of covariance after age adjustment reveals significant differences in patients with melancholic feature and patients with atypical feature in serum concentrations of triglyceride (TG) and very-low-density-lipoprotein cholesterol (VLDL) in men, and high-density-lipoprotein cholesterol (HDL) in women. This suggests that the TG, VLDL and HDL levels might be used as biological markers to differentiate between major depressive patients with melancholic feature or atypical feature.

Cholesterol in mood and anxiety disorders: review of the literature and new hypotheses

Cholesterol plays an integral role in the structure and function of the cell membrane and may also affect neurotransmission in the central nervous system. Previous work has identified abnormalities in serum cholesterol levels in patients with mood and anxiety disorders as well as in suicidal patients. However, the biological significance of these abnormalities remains to be clarified. An understanding of how serum cholesterol relates to the pathophysiology of mood disorders may generate biological markers that predict treatment response as well as targets for novel therapeutic strategies. In this article, we review the literature studying the significance of cholesterol in mood and anxiety disorders, with an emphasis on new studies focusing on the adverse impact of hypercholesterolemia on the treatment of major depressive disorder (MDD). We then propose possible mechanisms that would account for the relationship between elevated cholesterol and treatment non-response in MDD.

Correlation between serum lipid, lipoprotein concentrations and anxious state, depressive state or major depressive disorder

The purpose of this study was to investigate the correlation between serum lipid, lipoprotein concentrations and anxious state, depressive state or major depressive disorder. A total of 207 patients admitted for general health screening were recruited during a 1-year period. Using the Chinese Health Questionnaire, the Taiwanese Depression Questionnaire and the semi-structured clinical interview for DSM-IV, one psychiatrist screened all participants for the presence of anxiety or depressive disorders. Blood samples for serum lipid and lipoprotein concentrations and physical examination records were collected simultaneously. For patients who did not have systemic diseases (n=162), we found that high-density lipoprotein (HDL) cholesterol and the ratio of total cholesterol (TC)/HDL differed significantly among anxious state, depressive state and normal groups in men after age adjustment. On the other hand, the ratios of TC/HDL and low-density lipoprotein (LDL)/HDL showed significant differences between patients with major depressive disorder and normal controls in women. This study suggested that the level of HDL cholesterol and the ratios of TC/HDL and LDL/HDL (atherogenic index) might be another markers of the possible association between serum lipids and anxiety or depression.

Elevated cholesterol levels associated with nonresponse to fluoxetine treatment in major depressive disorder

Previous studies have suggested that patients with major depressive disorder may have lower cholesterol levels compared to healthy controls. The purpose of this study was to examine the relationship between pretreatment serum cholesterol levels and clinical response to treatment with fluoxetine among outpatients with major depression. Three hundred and twenty-two depressed outpatients meeting DSM-III-R criteria for major depressive disorder were enrolled in an 8-week, fixed-dose, open trial of fluoxetine 20 mg/day. Nonfasting serum cholesterol levels were obtained for all patients before starting fluoxetine. All patients were drug free for a minimum of 2 weeks prior to the onset of the study. Clinical response was defined as a 50% or greater decrease in the 17-item Hamilton Rating Scale for Depression (HAM-D-17) score at endpoint compared to baseline. Cholesterol levels were classified as either elevated (defined as a level equal to or greater than 200 mg/dL) or nonelevated (defined as a level less than 200 mg/dL). Among the 322 outpatients, 51.6% were classified as having elevated and 48.4% as having nonelevated cholesterol levels at baseline (mean cholesterol level 238.6 +/- 33.4 mg/dL vs. 170.4 +/- 22.2 mg/dL, respectively). Depressed patients with elevated cholesterol levels did not significantly differ in gender ratio but were significantly older than depressed patients with nonelevated cholesterol levels (P <.0001). After adjusting for age, gender, and Body Mass Index (BMI), depressed patients with elevated cholesterol levels were significantly more likely to be nonresponders to fluoxetine treatment than were depressed patients with nonelevated cholesterol levels (P < 0.05). Elevated serum cholesterol levels appear to be associated with poorer response to fluoxetine treatment. Further studies are needed to confirm our findings.

Correlation between serum lipid concentrations and psychological distress

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.

Lowered omega3 polyunsaturated fatty acids in serum phospholipids and cholesteryl esters of depressed patients

Depression is associated with a lowered degree of esterification of serum cholesterol, an increased C20:4omega6/C20:5omega3 ratio and decreases in omega3 fractions in fatty acids (FAs) or in the red blood cell membrane. The aims of the present study were to examine: (i) serum phospholipid and cholesteryl ester compositions of individual saturated fatty acids (SFAs), monounsaturated FAs (MUFAs) and polyunsaturated FAs (PUFAs) in major depressed patients vs. healthy volunteers; (ii) the relationships between the above FAs and lowered serum zinc (Zn), a marker of the inflammatory response in depression; and (iii) the effects of subchronic treatment with antidepressants on FAs in depression. The composition of the FAs was determined by means of thin layer chromatography in conjunction with gas chromatography. Lipid concentrations were assayed by enzymatic colorimetric methods. The oxidative potential index (OPI) of FAs was computed in 34 major depressed inpatients and 14 normal volunteers. Major depression was associated with: increased MUFA and C22:5omega3 proportions and increased C20:4omega6/C20:5omega3 and C22:5omega6/C22:6omega3 ratios; lower C22:4omega6, C20:5omega3 and C22:5omega3 fractions in phospholipids; lower C18:3omega3, C20:5omega3 and total (sigma)omega3 FAs, and higher C20:4omega6/C20:5omega3 and sigmaomega6/sigmaomega3 ratios in cholesteryl esters; lower serum concentrations of phospholipids and cholesteryl esters; and a decreased OPI. In depression, there were significant and positive correlations between serum Zn and C20:5omega3 and C22:6omega3 fractions in phospholipids; and significant inverse correlations between serum Zn and the sigmaomega6/sigmaomega3, C20:4omega6/C20:5omega3, and C22:5omega6/C22:6omega3 ratios in phospholipids. There was no significant effect of antidepressive treatment on any of the FAs. The results show that, in major depression, there is a deficiency of omega3 PUFAs and a compensatory increase in MUFAs and C22:5omega6 in phospholipids. The results suggest that: (i) there is an abnormal metabolism of omega3 PUFAs in depression; (ii) the FA alterations in depression are related to the inflammatory response in that illness; and (iii) the disorders may persist despite successful antidepressant treatment.

Assessing the observed relationship between low cholesterol and violence-related mortality. Implications for suicide risk

Health advocacy groups advise all Americans to restrict their dietary intake of saturated fat and cholesterol as an efficacious and safe way to lower plasma cholesterol concentrations and thus reduce the risk of coronary heart disease and other atherosclerotic disorders. However, accumulating evidence suggests that naturally low or clinically reduced cholesterol is associated with increased nonillness mortality (principally suicide and accidents). Other evidence suggests that such increases in suicide and traumatic death may be mediated by the adverse changes in behavior and mood that sometimes accompany low or reduced cholesterol. These observations provided the rationale for an ongoing series of studies in monkeys designed to explore the hypothesis that alterations in dietary or plasma cholesterol influence behavior and that such effects are potentiated by lipid-induced changes in brain chemistry. In fact, the investigations in monkeys reveal that reductions in plasma cholesterol increase the tendency to engage in impulsive or violent behavior through a mechanism involving central serotonergic activity. It is speculated that the cholesterol-serotonin-behavior association represents a mechanism evolved to increase hunting or competitive foraging behavior in the face of nutritional threats signaled by a decline in total serum cholesterol (TC). The epidemiological and experimental data could be interpreted as having two implications for public health: (1) low-cholesterol may be a marker for risk of suicide or traumatic death and (2) cholesterol lowering may have adverse effects for some individuals under some circumstances.

Lower serum high-density lipoprotein cholesterol (HDL-C) in major depression and in depressed men with serious suicidal attempts: relationship with immune-inflammatory markers

Recently, there have been some reports that changes in serum lipid composition may be related to suicide, major depression and immune-inflammatory responses. Findings from our laboratory suggest that major depression is accompanied by reduced formation of cholesteryl esters and perhaps by impairment of reverse cholesterol transport. The latter is reportedly accompanied by lower serum high-density lipoprotein cholesterol (HDL-C). The aim of this study was to examine whether (i) major depression is accompanied by lower serum HDL-C or by abnormal levels of serum total cholesterol, triglycerides, low-density lipoprotein-C (LDL-C) or vitamin E, (ii) suicidal attempts are related to lower serum HDL-C and (iii) there are significant associations between serum HDL-C and immune/inflammatory markers. A total of 36 subjects with major depression, of whom 28 patients showed treatment resistance, as well as 28 normal control subjects, had blood sampled for the assay of the above lipids, serum zinc (Zn), albumin (Alb) and flow cytometric determination of the T-helper/T-suppressor (CD4+/CD8+) T-cell ratio. In total, 28 depressed subjects had repeated measures of these variables both before and after treatment with antidepressants. Serum HDL-C and total cholesterol, as well as the HDL-C/cholesterol ratio, were significantly lower in subjects with major depression than in normal controls. Serum HDL-C levels were significantly lower in depressed men who had at some time made serious suicidal attempts than in those without such suicidal behaviour. Treatment with antidepressants for 5 weeks did not significantly alter either serum HDL-C or other lipid variables. Serum HDL-C levels were significantly and negatively correlated with the (CD4+/CD8+) T-cell ratio, and positively correlated with serum Alb and Zn. These results suggest that (i) lower serum HDL-C levels are a marker for major depression and suicidal behaviour in depressed men, (ii) lower serum HDL-C levels are probably induced by the immune/inflammatory response in depression and (iii) there is impairment of reverse cholesterol transport from the body tissues to the liver.