EagleTribune.com, North Andover, MA

June 9, 2013

Is aggressiveness hereditary?

Family Matters
By Larry Larsen

---- — Dear Doctor,

Is it possible for aggressiveness and anger to run in families; to be inherited? My husband and I agree that our 13-year-old daughter is just like my mother-in-law, to be her twin. My mother-in-law is difficult just like her grandchild is beginning to be.


Dear Hopeful,

Thirteen years of age should be a diagnosis. Mothers-in-law are by tradition difficult.

With that being said, the answer to your question is “yes” and “no.” Current research suggests a theory that is “epigenetic.” Let me explain.

The term “epigenetic” refers to being both inherited and learned. Most behavior is a combination of both.

There are strictly neurogenic models for differences in aggressiveness. For example, testosterone levels vary from person to person, and neuron receptors in the amygdaloid structure in the brain are particularly sensitive to that hormone. The amygdaloid structures appear to have a role in aggressiveness.

On the other hand people with particularly positive parenting experiences may have high testosterone, but are not especially aggressive. These patterns may be inherited.

We also know, from animal studies, that good mothering actually changes the neurology with increased production of neurons in areas producing more positive behavior.

So, my advice is to be the best mother you can be, especially with address to your daughter’s behavior. Do not reward it or become codependent. At the same time, offer her regard and affection, even in spite of her behavior. Teach and help her problem solve, but do not lecture or preach.

By all means avoid comparing her with your mother-in-law. Your job is to shape traits you see in your daughter.

Her stubborn streak can be fidelity. Her temper can also be assertiveness and energy. Teens eventually become human and likely someone else’s mother-in-law.

Dr. Larry Larsen is an Andover psychologist. Email him questions or comments at lrryllrsn@CS.com.