Personality Disorders: Are Their Brains “Fixed?”

People are far more adaptable than many therapists and researchers think.

Posted Jun 09, 2020

Flickr, arrested development Netflix special by Marco Verch, CC by 2.0
Source: Flickr, arrested development Netflix special by Marco Verch, CC by 2.0

People of any age can learn new information and change their behavioral responses to a wide variety of environmental contingencies. If that were not true, it is highly unlikely that homo sapiens would have survived as a species. After all, we are relatively small, not particularly swift runners, and have no natural armor or large talons with which to defend ourselves. And yet, here we are.

The entire practice of psychotherapy is predicated on the view that change is possible. If people become immutable by a certain age, then how would therapy ever help them change?

Ironically, however, some practitioners of psychology insist that most of our habits are completely fixed during childhood. According to the early psychoanalysts, for example, our personalities are completely developed by the time we are 5 years old. People with borderline personality disorder were thought to have “fixated” at the age of two. This meant that any psychological development after that completely stopped.

Neuroscience data is cited by many of today’s “biological” psychiatrists. They often make assertions based on study results that have limited applicability to the psychological phenomena under discussion, or have no basis in findings from the studies whatsoever. A book that came out way back in 1999, The Myth of the First Three Years by John T. Bruer, Ph.D., describes a particular heinous example of pseudo neuroscience that took hold with the participation of several politicians and celebrities. The misinformation is thoroughly dissected by Bruer.


The argument is this: the neurons in the brain develop thousands of synaptic connections per second until we reach the highest number of such connections around age 3. The connections then start to be pruned. This means that the number of synaptic connections decreases over time. Therefore, kids under three need to be properly stimulated. They must be read to, learn their ABC's as early as possible, attend pre-schools, and listen to a lot of classical music. If not, a window of opportunity will be closed forever.

This idea has led to much parental guilt and anxiety, which is far more damaging to kids' psychological development than not hearing enough Mozart. Because of kin selection, we are probably more affected by the emotional state of our attachment figures than pretty much anything else that isn’t extremely severe.

Parents who think they may have damaged their child by, say, putting them in the wrong day care program often become emotional wrecks who then overindulge their children, trying to prevent them from experiencing any or all emotional stress. When they fail at that, as they must, they may then at times react with fury or even strike a child physically.


In reality, synaptic pruning probably leads to much higher brain efficiency in reacting to the environment, but some people got the incorrect idea that the loss of neural connections after age three means something entirely different. They think that the period between ages 0-3 determines your IQ among other things, and if we want smarter and more resilient kids we must provide the proper stimulating environment or the development of our future abilities will be compromised severely. 

It is true that some aspects of the nonsensical idea may have limited applicability to some of our psychological abilities — like learning a second language without having an accent — which is almost impossible to do after the age of 12-14. But to think that somehow all of our abilities are like that is nonsense. Undoubtedly some of the neuroscience described in Bruer's book has become out of date due to increases in our knowledge base in the last decade, but I think his basic premises remain intact.

Most neuronal tracks in the brain are plastic in that new ones can form, and old ones become stronger or weaker, over one’s entire lifetime. However, certain nerve tracks in the limbic system that are conditioned by one’s attachment environment to respond with fear are highly resistant to major alterations. Certain faces — faces of kin — may trigger and reinforce a lot of automatic social responses to different people and situations.

The idea that children who are exposed to environmental events develop immutable brain changes — other than those exceptions just mentioned — has affected the highly important research in adverse childhood experiences like child abuse. Researchers do brain scans of abuse victims as adults and compare them to controls who had more loving childhoods, and differences in the size and activity of certain tracks remain. Hence, these researchers illogically state, these brain changes are now irreversible.

I doubt it. The folks that do the studies on untreated adults seem to think, because subjects are no longer being actually beaten or molested, that the involved brain tracks are no longer being strengthened through environmental reinforcement. That also must mean that continued negative interactions with the attachment figures have come to a complete stop. Nonsense. These children continue to be around them throughout their lives, or in some cases do cut them off, but hear about them through other relatives. The “different” brain structures are thusly maintained. If that reinforcement were to be corrected, maybe those tracks would start to revert back to the size and activity levels seen in the control subjects. 

In order to know, scientists have to take into account whatever happened in childhood plus everything that happened afterwards.

There is already some limited evidence now that some of the changes can modulate with therapy, as described in a recent review article in the German journal Nervenarzt (November 2018) by Schmahl, Niedtfeld & Herpertz. Their conclusion: Although the overall database is still sparse, clinical improvement in psychotherapy appears to be associated with modulation of brain structure and function… An important finding is the reduction of initially increased amygdala activity after successful Dialectical Behavior Therapy (DBT).