The Enneagram and Brain Chemistry

by Eric S. Schulze, MD, Ph.D., and Tina Thomas, RN, DCSW

The Enneagram has proven to be a very precise and predictable grid for the description of human personality. We believe that not only is the Enneagram a powerful descriptive tool, but also that it belies a biological truth that has yet to be discovered. In this article we will outline our theory on the biological basis of personality based on the Enneagram. We believe that this theory is an important step towards identifying the chemical and genetic "elements" that form the basis of personality.

We propose that the Enneagram (that is, the 9 basic types with wings, the Triads, the Hornevian groups, and the Harmonic groups) is explained by genetically determined high, medium or low levels of three dominant amine central nervous system neurotransmitters. Neurotransmitters are chemicals that modulate brain activity in predictable patterns. These three are Dopamine, Serotonin, and Norepinepherine.

Dopamine can be considered a basic modulator of physical endurance or drive. Serotonin can be considered a basic modulator of psychological well being. Norepinepherine can be considered a basic modulator of focused thinking and mental drive.

We hereby propose a theory of personality whereby high, medium, and low activity of each of these three neurotransmitters systems are distributed in an enneagrammitically logical way. We propose that the basic triad groups (Head, Gut and Heart) correspond to the level of activity of the Norepinepherine system. The thinking triad types (5, 6, and 7) appear to have high levels of norepinephrine activity and are generally mentally active. The instinctual triad types (8, 9, and 1) appear to have relatively low norepinephrine activity, and the heart triad types (2, 3, and 4) appear to have medium levels of activity of the norepinephrine system. We believe that the activity of Dopamine corresponds to the Hornevian Triads (Assertive, Passive, and Compliant). The assertive group (3, 7, & 8) has high levels of dopamine activity and have a lot of energy and drive. The passive group (4, 5, & 9) has low levels while the compliant group (1, 2 & 6) has medium levels. Finally, thanks to work of Riso and Hudson who identified the Harmonics, a third way of categorizing the Enneagram, the levels of Serotonin correspond to the Harmonic System (Positive Outlook, Reactive, and Competency groups). The positive outlook group (7, 9, & 2) has high levels of Serotonin and generally has an upbeat outlook on life, the reactive group (4, 6, & 8) has the lowest levels, and the competency group (1, 3, & 5) has intermediate levels.

Ordering each of the basic nine personality types in combinations of high, medium, and low neurotransmitters yields the following results:

You can see by the above tables that there is a certain symmetry to the assignments, and we believe that this has predictive value. We believe that the Enneagram is therefore as important and predictive for psychology and psychiatry as the periodic table of the elements is to chemistry and physics. The above table could explain why certain psychoactive medications such as Prozac (a SSRI, selective serotonin reuptake inhibitor) work on some people, cause unwanted side effects on others, and have no effect on others. We are currently studying whether certain medications, and even foods and activities can be helpful based on the above types and their neurochemistry.

In addition, we believe that "winging out" and disintegrating are a result of changes in the usual balance in the relative relationships of these neurotransmitters. Integration then, may also be a result of manipulating the same chemicals in such a way as to create a more balanced neurochemistry. We believe that medication, food, music and exercise influence the relative activity of these neurotransmitter systems, and that by rational manipulation of these effectors we can help people towards balance and integration.

This is a rough draft of our theory on the biological basis of personality that raises more questions than it answers. There have, however, been tantalizing recent reports in the scientific literature correlating certain personality traits with the activity of these three neurotransmitters. We are about to begin our own research project utilizing functional MRI to look for correlation between Enneagram defined personality traits and the activity of these three neurotransmitters.

We are quite cognizant of the debate on the relative contributions of nature versus nurture towards the development of personality. We have become convinced that nature determines type, but nurture determines health within the type, and interestingly also determines variant (Social, Sexual, and Self-preservation). We have formed a theory on the environmental basis of variant, and are developing a testing instrument to test our hypothesis.

Our theory is that variant is determined in the first 18-24 months, and relates to the organization of the family unit and its health. Specifically we believe that social variant types were raised in households with multiple "care-givers" such as is seen in multigenerational home settings more common in the past, and split care families common these days where a child may be raised in multiple homes with multiple "Moms, and Dads" due to divorce and economic influences.

Sexual variant people, we believe, are products of either "Traditional" homes with Mom, Dad, and 1.5 kids, or in single parent households with strong generally healthy ties with the "primary care-giver".

Finally, self-preservation variant types are, we believe, those who for whatever reason, death, illness, disruption, or sibling displacement had a problem with their relationship with their "Primary care-giver(s)" during the critical (18-24 month) period of development of their variant.

We believe that variant is likely a cultural by-product. Pre-historic humans were generally organized into either nomadic or agrarian communities. In many nomadic cultures, each family unit predominantly fends for itself, so the children in those families would carry a survival advantage if they formed tight bonds with their mother. In agrarian communities the family unit was frequently multigenerational, so the children in those families carry a survival advantage if they can "hang" with the social group. In either of these settings if there was some disruption or dysfunction in the relationship of the child with its caregivers, then the child would have a survival advantage if it could fend for itself. We believe that variant is therefore determined in the first 18-24 months and depends on the child's home environment. This would explain why there is a preponderance of certain variants in different cultures around the world depending on the dominant family organization within that culture.

Return to Top

The Enneagram Institute is a Service Mark of Enneagram Personality Types, Inc.
All Images, Content and Layout Copyright The Enneagram Institute 1998-2008.

[Home] [Back to Top] [Free RHETI Sampler] [Free QUEST Test] [Full RHETI Enneagram Test] [QUEST–TAS Test] [IVQ Instincts Test] [The Enn. Cards–Sorts] [Interpreting Test Results] [Type Descriptions] [How the System Works] [Levels of Development] [The Traditional Enneagram] [Practical Applications] [Relationships—Type Compatibilities] [Personal Growth] [Enneagram & Spirituality] [Addictions & Type] [Business Resources] [Enneagram FAQs] [Articles & Interviews] [Discussion Board] [Free EnneaFeatures Viewer Download] [Free RHETI Sampler Download] [Free Materials] [Books & Resources] [Schedule] [Training Program] [Workshops] [Private Consultations] [About The Institute] [Institute Network] [Teachers & Referral Listing] [Guestbook] [Contact The Institute]