Cholesterol, depression and suicide

Pathophysiological mechanisms of post-myocardial infarction depression: a narrative review

Myocardial infarction (MI) can have significant physical and mental consequences. Depression is a prevalent psychiatric condition after MI which can reduce the quality of life and increase the mortality rates of patients. However, the connection between MI and depression has remained under-appreciated. This review examines the potential connection between depression and MI by overviewing the possible pathophysiologic mechanisms including dysregulation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system, coagulation system dysfunction, inflammation, environmental factors, as well as, genetic factors. Furthermore, depression can be an adverse event of medications used for MI treatment including beta-blockers, statins, or anti-platelet agents. The need for early detection and management of depression in patients with MI is, therefore, crucial for improving their overall prognosis. Adherence to treatments and regular follow-up visits can ensure the best response to treatment.

Deficiency or activation of peroxisome proliferator-activated receptor α reduces the tissue concentrations of endogenously synthesized docosahexaenoic acid in C57BL/6J mice

BACKGROUND/OBJECTIVES

Docosahexaenoic acid (DHA), an n-3 long chain polyunsaturated fatty acid (LCPUFA), is acquired by dietary intake or the in vivo conversion of α-linolenic acid. Many enzymes participating in LCPUFA synthesis are regulated by peroxisome proliferator-activated receptor alpha (PPARα). Therefore, it was hypothesized that the tissue accretion of endogenously synthesized DHA could be modified by PPARα.

MATERIALS/METHODS

The tissue DHA concentrations and mRNA levels of genes participating in DHA biosynthesis were compared among PPARα homozygous (KO), heterozygous (HZ), and wild type (WT) mice (Exp I), and between WT mice treated with clofibrate (PPARα agonist) or those not treated (Exp II). In ExpII, the expression levels of the proteins associated with DHA function in the brain cortex and retina were also measured. An n3-PUFA depleted/replenished regimen was applied to mitigate the confounding effects of maternal DHA.

RESULTS

PPARα ablation reduced the hepatic Acox, Fads1, and Fads2 mRNA levels, as well as the DHA concentration in the liver, but not in the brain cortex. In contrast, PPARα activation increased hepatic Acox, Fads1, Fads2 and Elovl5 mRNA levels, but reduced the DHA concentrations in the liver, retina, and phospholipid of brain cortex, and decreased mRNA and protein levels of the brain-derived neurotrophic factor in brain cortex.

CONCLUSIONS

LCPUFA enzyme expression was altered by PPARα. Either PPARα deficiency or activation-decreased tissue DHA concentration is a stimulus for further studies to determine the functional significance.

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.

Low HDL cholesterol is associated with suicide attempt among young healthy women: the Third National Health and Nutrition Examination Survey

BACKGROUND

Serum cholesterol is reported to be associated with suicidality, but studies conducted among general healthy population are rare. We examined the association between serum cholesterol and suicidality in a national sample of the general population of US.

METHODS

We used the data of 3237 adults aged 17 to 39 years, who completed a mental disorder diagnostic interview and had blood specimens collected after a 12-h fast, as a part of the Third National Health and Nutrition Examination Survey, 1988-1994. The serum concentrations of total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were dichotomized according to the recommended levels of the National Cholesterol Education Program. A polytomous logistic regression was employed to control for covariates.

RESULTS

Independent of socio-demographic variables, health risks and nutrition status, and a history of medical and psychiatric illness (including depression), a significant association between low HDL-C (< or = 40 mg/dl) and increased prevalence of suicide attempts was observed in women (OR=2.93, 95% CI=1.07-8.00). No significant evidence was found to support an association between cholesterol and suicide ideation in women. Serum cholesterol was unrelated with either suicide ideation or attempts in men.

LIMITATION

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

CONCLUSIONS

Low HDL-C is significantly associated with suicide attempts in women. Further studies are necessary to explore the clinical application of serum cholesterol as an indicator for suicide attempts among high risk population.

The UCSD Statin Study: a randomized controlled trial assessing the impact of statins on selected noncardiac outcomes

There has been persistent controversy regarding possible favorable or adverse effects of statins or of cholesterol reduction on cognition, mood and behavior (including aggressive or violent behavior), muscle function, and quality of life. The UCSD Statin Study seeks to ascertain the beneficial or adverse effects of statin cholesterol-lowering drugs on a set of noncardiac endpoints, including cognition, behavior, and serotonin biochemistry. The study will enroll 1000 subjects (minimum 20% female) of mixed ethnicity from San Diego. Subjects must be age 20 and older, postmenopausal if female, without known cardiovascular disease or diabetes, and with LDL-cholesterol between 115 and 190 mg/dl. Subjects will be randomized to a double-blind, placebo-controlled trial with assignment 1/3, 1/3, 1/3 to placebo, simvastatin 20 mg, or pravastatin 40 mg (equipotent LDL-cholesterol-lowering doses for drug arms with simvastatin and pravastatin chosen to represent the extremes of the lipophilicity spectrum) for 6 months of treatment followed by 2 months postcessation follow-up. Primary outcomes are cognition (cognitive battery), irritability/aggression (behavior measure), and serotonin (gauged by whole blood serotonin), assessed as the difference between baseline and 6 months, judging combined statin groups vs. placebo. Secondary outcomes include mood (CES-D and Wakefield depression inventory), quality of life (SF-12V), sleep (Leeds sleep scale, modified), and secondary aggression measures (Conflict Tactics Scale; Overt Aggression Scale, Modified). Cardiovascular reactivity will be examined in a 10% subset. As additional secondary endpoints, primary and selected secondary outcomes will be assessed by statin assignment (lipophilic simvastatin vs. hydrophilic pravastatin). "Reversibility" of changes, if any, at 2 months postcessation will be determined. If effects (favorable or unfavorable) are identified, we will seek to ascertain whether there are baseline variables that predict who will be most susceptible to these favorable or adverse noncardiac effects (i.e., effect modification).