The Importance of Cholesterol in Psychopathology: A Review of Recent Contributions

Abstract

Aim:

The aim of this study was to describe systematically recent studies that show the importance of cholesterol in psychopathology.

Methods:

This study was a review. The following databases were searched for relevant published articles on human studies: MEDLINE, Web of Science, EBSCOhost Academic Search Complete, and Psychology and Behavioral Sciences Collection (papers from January 2012 to March 2016).

Results:

Eighteen recent papers were selected, and thematic dimensions showing correlations between cholesterol and behavioral and psychopathological variables were depression, suicide, personality, and aggression.

Conclusion:

This paper demonstrates that recent research corroborates the idea that cholesterol plays an important role in governing behavior and psychopathology in humans. Deepening the studies in this field could be a promising avenue for future research, with implications for treating people with behavior or mental health problems.

INTRODUCTION

Necessary for the healthy functioning of cells, cholesterol is a soft, fat-like, waxy substance that is moved around in the bloodstream by lipoproteins. Elevated levels of low-density lipoprotein (LDL or “bad” cholesterol) in the blood contribute to the formation of plaque in the arteries, which make them less flexible and increase the risk of blood clots. In contrast, high-density lipoprotein (“good” cholesterol) carries cholesterol away from arteries back to the liver where it is processed out of the body. Finally, triglycerides, a form of fat made by the body, are typically considered the third component of lipoprotein profiles; as with LDL, elevated levels of triglycerides contribute to the development of atherosclerosis.[1]

Abnormal or pathological serum lipid levels have been identified as important risk factors for coronary heart disease.[2,3] Substantial individual variations in lipid levels suggest that psychological factors might affect these levels. Therefore, a considerable amount of effort has been devoted to understanding the factors, from the cellular to the psychological, that contribute to high (and low) levels of cholesterol. Interest in the interface between psychological variables and cholesterol levels has focused mainly on the context of mood and anxiety disorders[4] and suicide.[5]

A body of research spanning several decades has identified a significant association between cholesterol levels and serious behavioral problems, wherein individuals with lower overall levels of cholesterol display significantly higher levels of antisocial and violent criminal behavior than their counterparts.[6] Along the same lines, several studies have shown that individuals with lower levels of cholesterol are more likely to score higher on measures of aggression and anger[7] and have a higher risk of displaying impulsive and violent suicidal behaviors[8] to name just a few.

Although there is strong evidence that cholesterol is involved in the occurrence of psychological symptoms, it must be remembered that cholesterol itself does not directly cause behaviors but may induce chemical changes, affecting the likelihood of certain behavioral outcomes as a result of modulation of particular neural pathways. Furthermore, cholesterol is only one of a myriad of influences on human behavior such as cognition and environmental circumstances.

Scientists are limited in that they cannot perform experimental procedures in humans. As such, we should remember that correlation does not necessarily indicate causation, and in many studies, such assumptions have been made. Before experiments can be done to investigate these correlations, we need to be sure that the types of behavioral variables we are looking into are cholesterol-dependent and eliminate other factors that could confound the results. Therefore, the purpose of this review is to describe systematically recent studies that show the importance of cholesterol in human behavior and psychopathology.

METHODS

Search strategies

I searched MEDLINE, Web of Science, EBSCOhost Academic Search Complete, and Psychology and Behavioral Sciences Collection (from January 2010 to March 2016). As a search criterion, I used the following: cholesterol, serum lipids, behavior, mental health, psychopathology, aggression, suicide, and depression. No language restriction was applied.

Selection criteria

I limited my search to full text, published articles, and human studies from the past 6 years. Abstracts, case reports, and editorials were excluded. I also retrieved relevant references of included studies for my search. All studies that investigated the association between cholesterol levels and human behavior and psychopathology were considered.

Qualitative data synthesis

The primary analysis was conducted by organizing obtained research by thematic dimension: authorship, country, number of human participants, short description of methods, and main results.

RESULTS

Table 1 illustrates the systematic review process of identifying and describing relevant studies that demonstrate associations between cholesterol and behavioral and psychopathological variables. This section reports on 18 recent papers, and thematic dimensions showing correlations between these variables were depression, suicide, personality, and aggression.

Table 1.

List of 18 references from 2012 to 2016 associating cholesterol levels with behavioral and psychopathological variables

DISCUSSION

Cholesterol has long been associated with various behaviors and mental health problems. This review highlights the latest key issues in lipidology and behavior and then provides a brief summary of the research into various associations between cholesterol and personality and psychopathology. Some evidence in support of the assumption is found for the following indicators: Depression, suicide, personality, and aggression; however, some critical issues regarding cholesterol-behavior/psychopathology relationships are also raised. Lipoproteins do not directly change behavior; they influence the expression of behavior within appropriate environmental/social contexts. When studying human behaviors, identifying which environmental/social contexts might be important remains a significant challenge to researchers trying to identify cholesterol-behavior/psychopathology relationships.

Research questions concerning the activational effects of cholesterol can now be more easily addressed because it is simple and relatively cheap to measure levels of circulating cholesterol and compare levels of observed behaviors and/or psychopathology. Bioavailable cholesterol can be measured in blood, and such testing can be conducted outside of a laboratory setting in various groups (e.g., patients, athletes) with basic training and equipment.

As it was observed from this review, different research paradigms can be adopted. The most commonly used was correlational – associating the level of cholesterol with a certain behavioral characteristic. More experimental designs should also be adopted, whereby cholesterol levels can be (a) compared between different groups, (b) compared within the same individuals in different situations, or (c) directly manipulated via cholesterol therapy.

This paper demonstrates that recent research corroborates the idea that cholesterol plays an important role in governing behavior and psychopathology in humans. Hence, can variations in circulating cholesterol activate changes in aspects of behavior and mental health? This is a pertinent question in light of the likelihood in the future of a substantial uptake of cholesterol.

CONCLUSION

Deepening the studies in this field could be a promising avenue for future research, with implications for treating people with behavior or mental health problems. It is clear that an enormous amount of work remains to completely understand the relationships between cholesterol and human behavior. Traditional research questions have focused on the role of cholesterol in behaviors, but it is becoming increasingly aware that this is not a simple linear relationship; the social context and intrapsychic factors might also play a significant role in determining cholesterol levels. This “chicken and egg” problem remains a key issue, and there are many questions that remain to be addressed and many variables that need to be considered. We are currently in an exciting period where cholesterol analyses are becoming cheaper and easier to conduct so that more endocrinology and behavioral scientists can begin to get involved in attempting to address these important questions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.