It is well known that elevated blood levels of cholesterol put you at risk for cardiovascular diseases, such as heart attack or stroke. How increased cholesterol levels relate to other diseases is less understood. Recently, several research groups reported an association between depression and altered levels of cholesterol in blood. The mechanisms involved in this relationship, however, are not understood at this time.
Evaluation of Lipid Profile
Cholesterol is a lipid molecule. As such, it is poorly soluble in water. In blood, cholesterol and other lipids are transported within particles whose surface is lined with water-soluble lipoproteins. Several types of those particles circulate in your blood. They differ in the amount of lipids inside them, which in turn affects their density. Two of those particles are especially important for evaluating your lipid profile. The low-density lipoprotein particles, or LDL, bring cholesterol from adipose tissue to cells of your body. LDL is also known as the bad cholesterol. The high-density lipoprotein particles, or HDL, bring the abundant cholesterol from cells around your body to the liver, where it is either used for the synthesis of other molecules or excreted via the gastrointestinal system in the form of bile acids. HDL is also called good cholesterol. The ratio of LDL to HDL is an important parameter used for predicting cardiovascular disease. In a healthy person, the ratio is 3.5 or less. Lipid profiles also include the assessment of triglyceride and total cholesterol levels. Their elevation is linked to cardiovascular diseases.
Altered Lipid Profiles and Depression
In the June issue 2010 of "Journal of Clinical Psychiatry," the research group of Dr. Brenda Pennix reported results from a study addressing the relationship between depression and lipid profiles. The study involved 2,400 subjects who were between ages 18 to 65. Patients with depression have significantly higher levels of triglycerides and lower levels of the good cholesterol, HDL, than the patients who remitted from depression. Further, a subgroup of patients with atypical depression had high levels of total and LDL cholesterol, the bad cholesterol. Another study by Marie-Laura Ancelin and co-workers involved 1,800 subjects. These researchers reported in the July 2010 issue of "Biological Psychiatry" that depression is associated with low HDL levels in women and high LDL levels in men. All these changes together suggest that patients with depression have disturbances in lipid profiles that classically imply higher risk for cardiovascular diseases. What role these changes play in depression needs to be addressed in future studies.
Low Levels of Cholesterol and Depression
Some subjects who attempted suicide have low levels of total cholesterol in their blood, as described by Dr. Alfonso Troisi in his report in February 2009 issue of "Neuroscience and Biobehavioral Reviews." At present, it does not appear low levels of cholesterol could be used as a marker for suicide risk. The reasons for low cholesterol levels in some of the patients remain unknown. Dr. Troisi also reports in the November issue of "Psychiatry Research" that low cholesterol levels are characteristic for a group of patients with impulsive behavior. Whether this could be related to the association with suicide is not known.
Conclusions
The relationship between lipid metabolism and mood disorders is very complex. Thus far, researchers have demonstrated the existence of the relationship between altered lipid metabolism and mental health. It remains unknown whether the metabolic changes could cause depression or vice versa.
References
- "Physiological Basis of Medical Practice"; John B West MD, PhD, DSc; 1990
- "Journal of Clinical Psychiatry"; Associations Between Serum Lipids and Major Depressive Disorder: Results from the Netherlands Study of Depression and Anxiety (NESDA); van Reedt Dortland AK, et al.; June 2010
- "Biological Psychiatry"; Gender and Genotype Modulation of the Association between Lipid Levels and Depressive Symptomatology in Community-Dwelling Elderly (the ESPRIT study); Ancelin ML; July 2010
- "Neuroscience and Biobehavioral Reviews"; Cholesterol in Coronary Heart Disease and Psychiatric Disorders: Same or Opposite Effects on Morbidity Risk?; Troisi A.; February 2009
- "Psychiatry Research"; Low Cholesterol is a Risk Factor for Attentional impulsivity in Patients with Mood Symptoms; Troisi A.; November 2010
