HONOURS PROJECT
Beginning at… well, the beginning
It’s quite hard to believe, but you’re entirely made up of cells! Right when you were born and developed into an embryo, your cells were making their minds up about what they wanted to be – and eventually, some became bone cells, some became red blood cells, some became muscle cells…
In each of these cells, there’s something called a nucleus. Unlike the famed mitochondria – the powerhouse of the cell – the nucleus does something else – it stores your DNA! And here’s where genes come in.
A short introduction to genes and inheritance
You inherit two copies of each gene – one from your dad, and one from your mum. Genes are on chromosomes, which are the 23 pairs you learn in Biology! 23 are from your dad, and 23 from your mum – adding that up you’ve got 46, which is 23 pairs.
Genes are a bit hard to understand. To explain, I’ll use Kat Arney’s brilliant analogy! Think of the genome – lots of genes together – as a huge library of cookery books. The librarian of this library is super strict, and won’t let you take the books down to bring home; and realistically, you can’t start cooking in a library. So you’ve got to take your copy to the photocopier in the library, make a photocopy, and then bring this home to assemble your food.
Except, because of the nature of cooking, this recipe is likely to get damaged! So you’ve got to make your way back to the library again and make a new photocopy. If, let’s say, you’re organising a huge party and want to make lots of food for your many guests, you’re going to need multiple copies of your recipe so that you can find people to help you. It’s the same with genes – your DNA is read and made into proteins, which carry out the work that keeps you alive!
Bringing mental health into the picture
Research is still ongoing, but it’s been suggested that part of how depression and anxiety develop is associated with the production of various chemicals in our brain. Here’s a diagram that will hopefully help, taken from bestmastersinpsychology.com:
An example? Melatonin, another chemical that’s not mentioned in the diagram, is perhaps better known for its function – it’s the chemical that makes you want to sleep! The next time you’re sitting in class, wishing that the teacher would stop droning on about chemicals like dopamine and adrenaline, blame melatonin.
In summary, too much or too little of various chemicals in your brain is believed to lead to depression and anxiety.
…except the picture isn’t quite complete yet!
To this day, scientists are trying to figure out what exactly causes depression. There’s one thing we know for sure – it’s not just one thing that causes it but a mix of different factors! One is the balance of chemicals, as mentioned above; but another is your genes. We’ve not quite got which genes cause various mental disorders yet, though.
There’s proof already that mental illnesses run in families. Take bipolar disorder for example; half of those who struggle with it have a relative also dealing with the illness. If you’re an identical twin, which means you share your genetic makeup with your twin, and they have bipolar disorder, you’re at 60% to 80% risk of developing it (Every Day Health, 2013) . In contrast, if you were fraternal twins or any other type of sibling relationship that involves only about half of your genes being shared, you’d only have a risk of 20% (Every Day Health, 2013).
Genes, come out, come out, wherever you are!
‘We are finding large genetic variations, so there are probably multiple genes involved and different things that trigger those genes,’ says Dr Nimgaonkar, a psychiatrist at the University of Pittsburgh’s Medical Centre. A research study called the Psychiatric Genome-Wide Association Study Consortium, made by researchers of more than 20 countries, agrees. They’ve found that there are at least 11 – no, not genes – regions! that are strongly associated with mental disorders such as schizophrenia and bipolar disorder, and claim that neither of those two are caused by a single gene.
He continues, ‘It’s also important to know that even if you don’t inherit a gene for a mental illness, you can still have a genetic cause.’ It turns out that after your birth, genes can still change and contribute towards the development of mental illnesses! This is called a de novo mutation, and can either be hereditary or acquired.
A bit of an explanation: A hereditary mutation is inherited from one of your parents, and it will be present in every cell in your body. An acquired mutation will occur at some point in your life, perhaps because of exposure to ultraviolet light or mistakes during cell division, and affects only certain cells. De novo mutations are either, are genetic in this way, and can cause mental illnesses!
The complicated picture: The causes of mental illnesses
Here’s an interesting and reinforced fact: If your family member has a mental illness, you’re likely to have that mental illness. If everyone you’re related to doesn’t have depression, your risk is 10%. If, on the other hand, your family member does have depression, your risk increases by 20 to 30% (Every Day Health, 2013). That's a huge increase!
But the same studies on mental health show a different picture as well. Dr Meresh of the Loyola University Health System in Chicago states, ‘If your identical twin has schizophrenia, you’re only likely to have the disease around 50% of the time.’ So what are the other causes of mental disorders?
There are lots, of course. Some are trauma (which is in turn caused by various things), abuse, neglect and bullying, but there is a plethora of other causes for mental illnesses!
Is there a conclusion?
For now, not really. Scientists are delving deeper into the relationship between genetics and mental illnesses than ever before, but it seems that the more we know, the less we find that we actually know! It’s the hope that in the future, we’ll be able to develop personalised medicine for the treatment of every mental disorder! Until then, please know that you’re amazing and worthy of getting help.
DISCUSSION QUESTIONS
Which mental disorders do you think are passed down genetically?
Which mental disorder do you think is passed down genetically the most often?
Do you have any other suggestions for how we can think of the genome?
What are some questions you’d like answered regarding genes and their relation to mental health?
Do you think personalised medicine is possible?
LINKS
https://ghr.nlm.nih.gov/primer/basics/gene
https://www.theregister.co.uk/2006/05/19/the_odd_body_chromosomes_genes/
https://www.webmd.com/mental-health/brain-mental-illness
http://www.bestmastersinpsychology.com/science-mental-health/
https://www.health.harvard.edu/mind-and-mood/what-causes-depression
https://www.everydayhealth.com/depression/mental-iillness-may-be-in-your-genes-1751.aspx
https://www.cancer.gov/publications/dictionaries/genetics-dictionary/def/de-novo-mutation
https://ghr.nlm.nih.gov/primer/mutationsanddisorders/genemutation