The “Nature vs. Nurture” debate has been a hot topic and heavily researched question among mental health researchers and professionals. This is a big question for clients too! When individuals are diagnosed by a doctor, psychologist, or psychiatrist with a mental health concern, often they want to know “How did this happen?” “Why did this happen?” and “Is this genetic?”. These are all valid concerns - parents might worry that they did something wrong in raising their children, and some individuals may second-guess having children out of concern for passing along a condition with a strong hereditary factor.
The Impact of Nature
Simply speaking - yes, it does appear that many mental health conditions have strong evidence to suggest heritability (which means that it can be inherited). In particular, Major Depressive Disorder, Bipolar Disorder, ADHD, Schizophrenia, and Autism have been researched at length, and it appears that people living with these disorders have certain identifiable genes- and if you take a mental journey back to high-school biology, you may have learned that our genes are a mix of the traits we inherit from our biological parents. So, if your parents or grandparents have a history of mental health concerns, it is possible that the genetic makeup that contributed to these conditions may have been passed along to you. This being said, not every child receives every gene their parents possess - and even multiple children in the same family are not genetically identical (unless they are identical twins!)
Furthermore, not every person with the “genes” that might predispose them to developing a disorder actually do have the disorder - so what gives?
Picture this: Joe lives with depression - and he knows that his father also lived with depression. When Joe gets married to Sally, he expects that his children may also experience depression because both he and his father did. Out Sally and Joe’s three children, only one experiences depression. What’s happening there?
Nurture: It’s Broader than you Think!
When we discuss the “nature vs. nurture” debate, it’s important to remember that while nurture does have lots to do with how your parents cared for you, it also has to do with the rest of your environment! This includes doctors, teachers, friends, and anyone else who holds significant influence in your life.
In particular, it is clear that traumatic experiences and stress can create an environment where it is more likely for mental health concerns to appear. Experiences such as childhood abuse, violence, substance use, death of a loved one, witnessing a traumatic event, and bullying can all inform clinicians as to the contributors to mental health concerns.
This being said - it is not always a guarantee that a person who experiences a trauma will develop a mental health concern. People are resilient! It is also important to remember that while parents do everything they can to protect their children, us professionals know it’s impossible to protect them from everything, and acknowledge that sometimes traumas happen and it is not helpful to place blame.
Epigenetics: The “On/Off” Switch
In addition to the social and emotional environmental factors above, the chemicals we are surrounded by also have an impact on how our genetic makeup forms our health and personality!
A field of science called epigenetics explores how some genes appear to become “active” in some individuals, while the same genes remain “latent” or inactive in others. The theory is that some things in the environment - either exposure to certain substances and chemicals, or exposure to specific experiences - can prompt a gene to become active. This idea brings the “nature” side of the nature vs. nurture debate to the table. Although a person might carry the genes for a specific disorder or trait, there are environmental factors that can “turn on” or “turn off” some genes!
A great example of this concept is that scientists have identified an obesity gene in mice that appears to be “turned on” by BPH - a common component in manufacturing plastic bottles. When mice were exposed to the chemical, they developed obesity, while genetically identical mice that were not exposed to the chemical did not become obese. Fun fact: the fur of the exposed mice also turned yellow!
The Bottom Line
We know that many mental health concerns do have a genetic component, however whether or not a person actually develops a concern is also impacted by their life experiences and the environment they develop in. All this means that it is very complicated to try and pinpoint the “cause” of a mental health concern, and impossible (right now!) to accurately predict who will develop a concern and who will not - so we do the best we can in responding to concerns that arise, even if we are not able to state the cause with certainty!
Feel free to make an appointment to chat with a therapist about any mental health concerns you may have, or read more about the research I consulted below: