Where Do Mental Health Issues Come From?

Is it Nature? Nurture?

A combination of both?  And if it’s both, is one a greater factor than the other?

A recent study in the journal Nature Genetics (Poldesman et al. 2015) examined over 14.5 million pairs of twins to help answer this very important question.  To access this many people,  the researchers reviewed almost every twin study completed over the last 50 years.

Why twins?

Identical twins have almost 100% of the same genes, while fraternal twins have approximately 50% of the same genes. Both types of twins have similar environmental experiences.

By contrasting these two types of twins, it’s possible to tease apart the contributions of genetics and environment.

And what did they find?

The effect of genetics versus the environment is about 50/50.  And this is not only for mental health issues but for other factors such as physical health, personality, intelligence, etc.

Of course, there is some variation for specific mental health issues (e.g., Bipolar Disorder was found to be 70% genetics and 30% environment) but on average the numbers are 50/50.

Take Home Message:

If you are dealing with a mental health issue, there’s a good chance that both genetics and environmental factors played a strong role in the onset.  What’s important is identifying the issue, creating a plan to manage it and having a willingness to make mid-course corrections.

 

Were you surprised that nature and nature appear to contribute equally to the development of mental health issues? Is this finding reassuring or concerning? Please let me know in the comments section below.