Lowered Cholesterol levels have been associated with patients who have committed violent acts of suicide

Laura A. Urbin

East Tennessee State University

For presentation at

Research in Allied Health/ ALHE 4060

July 17, 2006

Lowered cholesterol levels have been associated with patients who have committed violent acts of suicide. Laura A. Urbin. Research in Allied Health Presentation at East Tennessee State University, Johnson City, Tn.

Abstract

            Suicide is a topic that has been studied over the years for many different reasons.  Most people feel that suicide is generally caused by a depressive disorder.  After much research being conducted it has been found that there are associations between suicide and other variables in a person’s life.  In this study I was able to find the association between violent acts of parasuicide and low levels of cholesterol in the patient.  Parasuicide is defined as an “act of a non-fatal outcome in which an individual deliberately initiates a non-habitual behavior that, without interventions from others, will cause self-harm…and which is aimed at realizing changes that the persons desire via the actual or expected physical consequences.”(Gallerani, 2005).  After studying the association between low levels of cholesterol and violent acts of parasuicide I came upon another variable that makes this association strong, that variable is the level of serotonin in the brain.  As cholesterol levels are lowered in a person’s body the level of serotonin in their brain is also lowered.  Serotonin, as defined by Engelberg (1992) is a chemical occurring naturally in the brain that suppresses harmful impulses such as suicidal or aggressive behavior.  So one can see why the lowering of cholesterol, leading to the depletion of serotonin levels, would become associated with violent acts of suicide as a result of impulsive behaviors no longer being subdued.    

Introduction

            Suicide is a topic that has been researched by many different fields in the medical world.  Many researchers want to know what variables can lead to suicide and why people commit suicide.  I did my research in order to prove an association between a patient having low levels of cholesterol and committing a violent act of suicide.  This research is important because it makes patients aware of possible outcomes from decisions that they make in regards to their health.  Most people are not aware of the fact that by lowering their levels of cholesterol they become at higher risk for committing a violent, aggressive act of suicide.  Acts of suicide can be placed into two categories which are violent acts, consisting of suffocation, shooting, drowning, cutting etc., and non-violent or low violent acts, consisting of ingestion of drugs, alcohol, petroleum derivatives, chemicals, etc. with the intent of dying.  In studies done regarding suicide it has been found that people who commit violent acts have a significantly lower level of cholesterol than those who commit non-violent acts or no suicide at all.  In doing my research and this study I hope to allow readers to obtain knowledge of the association between cholesterol levels and suicide attempts.

Problem Statement

            In my study I want to prove that there is an association between violent acts of suicide and low levels of cholesterol.  I looked at the main variable being the lowered level of cholesterol but I also came upon another variable in this study which is the level of serotonin in the brains of patients who have committed violent acts of suicide.  The issue that is studied in this research is that of why people commit violent acts of suicide and the situations that can lead to it.  I feel that suicide is a topic that should be heavily researched.  Every person at some point in there life has or will come in contact with a person who has committed an act of suicide or knows a person who has committed an act of suicide.  In the past I had thought that the people who commit suicide do it because they are severely depressed, but now I have found that this is not always the case.  I am not ruling out the fact that suicide is related to depression but I want to make people aware of the fact that by lowering their cholesterol the serotonin levels in their brain become depleted and in turn leads to more impulsive-aggressive behavior such as violent acts of suicide.   If people are given the opportunity to learn about causes of suicide then they will be able to take preventative actions to give a better chance of not committing the act themselves or helping someone else to not commit the act.

Review of Literature

Studies have shown that people who have committed violent acts of suicide have lower cholesterol levels than those who have committed non-violent acts of suicide, or no suicide at all.  Violent acts of suicide can be classified as those involving “deliberate self harm by hanging, suffocating, drowning, firearm shooting, use of explosives, fire and flames, cutting, jumping from a high place, or throwing oneself under a moving vehicle” as noted by Massimo Gallerani (1995).  Gallerani (1995) stated that after testing patients who had committed acts of parasuicide the results showed that those who had committed violent acts had a lower level of cholesterol than those who had not.  Gallerani (1995) defined parasuicide as “an act of a non-fatal outcome in which an individual deliberately initiates a non-habitual behavior that, without interventions from others, will cause self-harm…and which is aimed at realizing changes that the persons desire via the actual or expected physical consequences.” Lindberg (1992) also agrees with the association of lowered levels of cholesterol and violent acts, such as suicide, by stating that “lower serum cholesterol concentrations have been reported in criminals, people with violent or aggressive conduct disorders, and people with low self control.” Researchers in other studies have also found that “low serum total cholesterol was associated with low mood, and, subsequently, with depression leading to serious consequences.” (Low cholesterol levels and risk of suicide, 2002).  These studies also gave proof that “cholesterol concentrations were found to be lower in the parasuicide subjects than in the control group, even when differences were evaluated by dividing samples into subgroups by sex and by parasuicide method.” (Low cholesterol levels and risk, of suicide, 2002).   

 Wardle (1995) stated that “the idea that emotional factors might be linked to lipids is not new, but up until the 1980’s it was assumed that there would be a positive relationship between depression and cholesterol.”  This has been found to be the opposite.  A negative relationship has been found between depression and cholesterol levels.  Wardle (1995) also speaks of trials that have been done that “suggested that lowering cholesterol increased non-illness mortality” and that “ this was followed by a number of reports indicating that suicide levels were higher in low cholesterol groups and that depression was related to low cholesterol.” 

Gallerani (1995) also stated that “low serum cholesterol concentration may lead to a rise in suicide risk because serotonin in the brain is decreased.”  So, does lowering cholesterol lead to a decrease in serotonin levels and ultimately contribute to violent, aggressive acts of suicide?  Hyman Engelberg (1992) stated that “lower blood cholesterol concentration may decrease the amount of cholesterol in the cells membrane” and that “lower cell membrane cholesterol decreases the number of receptors in the brain for serotonin.”  Engelberg (1992) goes further to say that “fewer serotonin receptors decreases the amount of serotonin in the brain and may increase the likelihood of violent behavior.”  Serotonin, as defined by Engelberg (1992) is a chemical occurring naturally in the brain that suppresses harmful impulses such as suicidal or aggressive behavior.  Therefore we can see from these studies why if cholesterol levels are lowered, leading to decreased serotonin levels, we find people committing violent acts of suicide instead of non-violent ones.  As we decrease serotonin through cholesterol being lowered we find more impulsivity not being subdued.  Murad Atmaca (2004) agrees with this concept stating that “diminished serotonin activity has been discussed as the reason for many behavioral abnormalities such as suicide attempts, appetite changes, aggression, and sleep disturbance.”  Atmaca (2004) also stated that serum lipid concentrations play an important role in serotonin regulation and other psychological functions and it can play a role in effecting brain functioning and possible impulsive-aggressive behavior.

In this research I found out that cholesterol is “a major component of brain-cell membranes” and that “alterations in dietary cholesterol affect the fluidity and viscosity of the membranes which house receptors for serotonin.” (The cholesterol conundrum, 1995).  Wardle (1995)  states that “dietary fat intake has been shown to influence brain uptake of fatty acids, the phospholipids composition of neuronal cell membrane, and neuronal mitochondrial MAO activity.”  These findings go along with the information that has been provided regarding the association between lowered cholesterol and serotonin levels. 

We also find from the research that “a reduction of total cholesterol might alter the metabolism of serotonin, inducing depression or poor control of aggression, thus leading to an increased risk of suicide”(Low cholesterol levels and risk of suicide, 2002) which may “suggest a link between low or lowered fats or cholesterol levels and low or lowered serotonin activity.” (Low cholesterol levels and risk of suicide, 2002).  Dr. Jay Kaplan also followed along the lines of the serotonin depletion being associated with lowered cholesterol levels and suicide and stated that “people in cholesterol-lowering trials might have been experiencing impulsivity, which led to the higher rates of suicide and accidents.” (The cholesterol conundrum, 1995).

Some further studies have been done involving behaviors of primates that have been placed on a cholesterol lowering diet.  Lindberg (1992) stated that “a recent study showed changing behavior in monkeys who were fed with a diet low in saturated fat and cholesterol.” Muldoon (2001) concurs that “studies in primates have found that consumption of low fat and low cholesterol diets potentiates aggressive behavior and decreases social affiliation.”  This contributes to the association between lowered cholesterol levels and violent acts of suicide.  Most people who commit suicide begin to withdraw their self from society and from people around them and at the same time begin to show more impulsive, aggressive behavior. Kaplan also measured serotonin levels in monkeys who had been placed on a low cholesterol diet. He found that the “low-cholesterol aggressive monkeys had less serotonin than the high cholesterol monkeys.” (The cholesterol conundrum, 1995). “Nonhuman primates and other animals with naturally low or experimentally lowered serotonin measures are more aggressive” says Golomb (1998) and by “increasing low serotonin or restoring lowered serotonin to high values returns violent animals to a less aggressive disposition. Similarly, in humans, low serotonin is linked to increased impulsive violence…and to violent and repeated suicide attempts.”(Golomb, 1998)

            The research indicates that these impulsive-aggressive behaviors, such as the violent acts of suicide, are related to the lowered cholesterol levels.  Wardle (1995) says that “the neurobiology of aggression and depression, and perhaps of other negative affective states, points to an important role for serotonin” and that “there is enough evidence for dietary constituents affecting neurotransmitters, mood or behavior to suggest that dietary cholesterol-lowering could affect brain neurotransmitter systems more directly.”  Garland (2000) concurs that “it appears reasonable to hypothesis that low cholesterol as a trait, or as the desired result of cholesterol-lowering treatment, may in some way influence CNS function or act as a peripheral marker for factors governing predisposition to death by trauma and suicide.”  Garland (2000) goes further to state that “this hypothesis provides a model to address not only the phenomenon of excess suicides in those with low cholesterol, but also increased mortality from accidents and trauma.  Hyposerotonergic function is not just linked to depression, parasuicide and completed suicide, but it is also linked to aggression and impulsivity, which are crucial antecedents to accidents, trauma, parasuicide and suicide.”  Golomb (1998) states that “it is postulated that lowered cholesterol levels may lead to lowered brain serotonin activity; this may in turn lead to increased violence.” 

As research shows, we find that the lowered levels of cholesterol in people who have committed violent suicide attempts is not from cholesterol lowering drugs, but from a natural source.  This may come from a person changing dietary habits because of depression, which in turn depletes their cholesterol concentration leading to lower serotonin levels and ultimately to acts of aggressive suicide.  Muldoon (2001) stated that “a recent case- control study found that neither fatal nor non-fatal injuries were related to use of cholesterol lowering drugs.”  Although the association between lowering cholesterol levels and violent acts of suicide has been proven we do need to understand that this is not an association based on a person using cholesterol lowering drugs.  In the study done by Muldoon (2001) it was proven that these acts are not directly correlated to cholesterol lowering drugs but that these results “do not exclude the possibility of cholesterol reduction having adverse effects on psychological wellbeing or quality of life.” In the study of patients who had committed acts of suicide Gallerani (1995) included subjects whom had not used cholesterol lowering drugs before blood sampling.  In this way Gallerani (1995) was able to obtain results that showed people who had committed violent acts of suicide did have lower levels of cholesterol not based on any cholesterol lowering drug treatments.

Method

            I found the participants for my study through three hospitals in the tri-cites area in Tennessee, which were Holston Valley Medical Center, Bristol Regional Medical Center, and Johnson City Medical Center.  These patients ranged in age from 18 -75.  The criteria that had to be met for a participant to be entered into the study were that they had committed an act of suicide and had been admitted into the hospital.  For my experiment I replicated parts of previous experiments that were found in my review of literature.  After blood tests were drawn within 24 hours of the attempted suicide I obtained consent from the patients allowing me to place them into the study.  I used 331 patients who had committed acts of suicide between January 1, 2000 and February 15, 2002 and 331 patients as a control group out of 3000 patients who were admitted to the hospital during the dates mentioned above for other illnesses and had no history of suicide. All of these patients were chosen using the table of random digits, assigning each patient a number and using the table to decide which ones to include in the study.  I was aware of several variables that could possibly confound my study such as cholesterol lowering drugs, alcoholism, drug addiction, dietary intake, cancer, etc., and did not include the results from patients who had a further situation that could cause confounding of the results. The study was approved by the ETSU IRB after being presented with my method and Scales of Measurement. The ETSU IRB decided that I did not unnecessarily expose the patients in my study to any risk, that I discussed benefits and risks to patients in my study, although no physical, social, psychological, legal, or economical risks were found, that I provided them with the criteria that I used to choose my patients for the study and that I was not using vulnerable populations, that I would obtain informed consent from every patient included in my study, and that I would provide privacy to all patients involved in the study.  I followed all HIPAA guidelines in my study, keeping all participant information confidential.  All of the participants signed a consent form allowing the use of their blood samples for research purposes. My study was non-experimental and used ratio data meaning that the levels of cholesterol had equal intervals between them and that I was able to put the data on a scale containing a zero point.  My data used in the study are parametric because they are representative of the entire population and because I was able to match patients in each group according to similar patients in other groups. I matched the people who had attempted suicide with those in the control group on the basis of age, sex, diabetes, arterial hypertension, misuse of drugs, alcoholism, etc.(Gallerani 1995 p.1632)  I wanted to be able to show a relationship between two variables, level of suicide and level of cholesterol, by doing this study. So, once I was able to obtain my inferential and descriptive statistics and show how these variables were associated I was then able to run tests for significance in the results.  For my descriptive statistics I was able to compare the mean level of cholesterol between the groups in order to give proof of this relationship.  For my inferential statistics I used the single sample t test to compare the mean of each group to the rough population mean in order to see if the results were significant.  Also for my inferential statistics I used analysis of variance, or ANOVA, which helped me to compare the mean scores of all three groups at one time. The ANOVA test showed me that there was a significant difference between the mean scores of each group.  The blood samples that were taken from the patients were drawn at 7:00 am after having fasted over night.  After collecting my blood samples I went further to place the experimental group, those who had committed parasuicide, into two separate groups, violent and non-violent/low violence, in order to be able to compare those results as well.  The classification of suicide was based on the 25 categories that are mentioned in the International Classification of Diseases.  After completing my tests on the patients I was able to find that the violent suicide attempters had a significantly lower level of cholesterol (p<0.05 for violent versus non-violent suicide attempters and p<0.001 for violent suicide attempters versus the control group) (Atmaca 2004 p.24) than those patients contained in the other two groups.  I was able to conclude that violent suicide attempters do have lower cholesterol levels than those who have committed non-violent suicide attempts or no suicide at all.

Discussion

            After completing my study and research I have been able to prove my hypothesis that there is an association between lowered levels of cholesterol and violent or impulsive-aggressive acts of suicide.  When I first began my research I thought this association was merely caused by lowered cholesterol levels leading directly to acts of violent suicide, but after finishing my research and study I found that the depletion of serotonin levels in the brain caused by the lowered cholesterol levels also plays a major part in causing people to commit acts of violent suicide.  I feel that there is enough evidence to show that there is a valid association between cholesterol and suicide, with the serotonin being another independent variable in the study. 

Conclusion

            I had wanted to prove my hypothesis, the association between lowered levels of cholesterol and violent attempts of suicide, in this paper because I find suicide to be a much more complex issue than most people think.  By doing my research I was able to conclude that suicide is not directly related to the use of cholesterol lowering drugs, but actually to the level of cholesterol itself.  I do not think that patients should be fearful of using cholesterol lowering measurements to improve their health but that they should be made aware of the possible effects of lowering their cholesterol, which includes the benefits and the risks.   I would like to do further studies into the area of possibly including serotonin level enhancers for patients who are involved in cholesterol lowering measures.  I feel that this study, and others like it, is very important as more and more health improving measures are being used in the medical world.

Bibliography

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