Linking Poverty to Depression – Genes of Poorer Adolescent Children Permanently Labelled for Depressive Behaviour: Depression later in life can be influenced by early childhood events. It may be linked to similar conditions in our parents. Recent research has shown how this could be happening at the genetic level by turning-off key genes necessary for the transportation of serotonin – the body’s ‘happiness’ messenger. An explanation is provided of how disadvantages in childhood like extreme poverty, maltreatment, neglect or exposure to violence may trigger later depression – by permanently ‘tagging’ genes and turning them off. 

We all inherit a double set of genes from our parents, one set from our father via his sperm and the other set from our mother through her egg. These two sets combine in what is our first cell which then multiplies to create the billions of human cells that make up our body. In this way every human cell in our body starts off with the same two sets of genes (except for when we make our own sperm or egg cells – here our double set is halved so the cycle can continue when they meet up to create our children).

You inherit genes from your parents through the information coded in DNA – an incredibly long molecule that the genes are made from. You can think of DNA as a string of thousands of genes arranged rather like the beads on a necklace – each bead containing the information to manufacture a molecular component of the machinery that makes up our body. More recently we have discovered that these genes can be tagged or marked by adding a small molecular methyl group. One of the purposes of this methyl tagging process is to turn off the gene.

Turning off genes is important because not all of our genes are needed in every cell. For example the cells which make up the lens of an eye do not need to be able to produce the enamel which is normally found in teeth. However since all cells contain the same set of genes (in their ‘necklace’) they all have the instructions to make every component needed throughout the body. So to avoid every cell producing loads of stuff which would be useless for its specific job many of its genes are turned off as the body develops from the original single cell. A bit of the DNA molecule that is close to the gene has the ‘don’t make me‘ methyl tag attached to it.

When a gene is shut down using a methyl tag it usually stays shut down and even if the cell multiplies this gene can stay shut down (so all the new cells produced when this cell divides also get a methyl tag attached at the correct spot). This means that, early in our development, once eye cells have been tagged to not produce tooth enamel they and their offspring cells continue to have this enamel gene turned off. If this didn’t happen we might end up with teeth growing in the middle of our eyes!

Methyl tagging doesn’t just turn off ‘construction’ genes like those to make enamel or eye lens material. It also works on important messenger molecules that play a role maintaining our balanced psychological state. One of these messenger molecules (made by the gene SLC6A4) is involved in transporting the ‘happiness’ molecule serotonin which stimulates the nerve cells in our body (and importantly in our mind). If the SLC6A4 gene gets turned off using a methyl tag it will not be produced and can’t be involved in telling our nerve cells (and our mind) when happy times have arrived.

What do we mean by happy times? Well serotonin is produced in the gut when a big delicious meal has just landed on the table in front of us. It tells the gut muscles to start contracting so the food will move quickly through our digestive system and we can get the benefit of all those yummy nutrients. It also warns other important parts of the body ‘get ready – nosh is on the way’.

Serotonin also helps create a general psychological feeling of well being. This is important in evolution – it lets an animal know that tasty meals are good and should be consumed as often as possible. That’s why eating can make us happy. Problems preventing serotonin transport in the body have been associated with anxiety and depression – this is why you can think of it as the happiness molecule.

Recently the turning-off of the serotonin transportation gene SLC6A4 by methyl tagging has been linked to increased incidence of depression. Not surprisingly if you can’t use the happiness molecule serotonin you feel depressed. The levels of methyl tagging have been found to be increased when children had been subject to traumas such as childhood abuse or after they experience extreme levels of poverty (low socio-economic status). Once tagged these genes stayed tagged preventing the transport of serotonin which was associated with an increased incidence of anxiety, depression and related disorders later in life.

Last week research was published linking an increased in tendency towards later depression with experiences of lower socio-economic ‘stress’ in a group of 132 adolescent children (Molecular Psychiatry 24th May 2016: Swartz, J. R., Hariri, A. R. & Williamson, D. E.). The authors found that an experience of poverty in childhood causes increased methyl tagging (turning off) of the gene for serotonin transportation. They followed the development of these children, carrying out research at three different times, to demonstrate that this increased methyl tagging did indeed lead to an increased prevalence of depressive symptoms.

In addition to demonstrating this chain – poverty leading to methyl tagging leading to higher incidence of depressive disorders – the researchers also confirmed an increased likelihood of children from parents with depression also suffering from the same disorder. If methyl tagging is leading  to depressive symptoms this may well be being inherited – demonstrating what is known as an ‘epigenetic’ mechanism  for inheriting mental illness. A genetic mechanism is where information inside a DNA molecule is inherited – an epigenetic mechanism is where the DNA molecule has been altered by the cell and this alteration is passed to future generations. the use of methyl tagging to turn off a gene is an example of such a change.

This means that although a child may have a full complement of all the genes necessary for a happy and mentally balanced life some of these genes may actually be turned off permanently through poverty or some other trauma in childhood. The turning off may even occur to the DNA of the child’s parents causing the child to inherit its parents’ tendency towards depression. This could help to explain why some psychological symptoms like alcoholism, drug dependency, obsessive compulsive or anxiety related personality disorders appear to have a hereditary component.

I personally find this an exciting development – we are reaching a point with molecular biology where the chemical basis of clinical problems related to the mind and human psychology are starting to be understood. Understanding how conditions in a person’s environment or inherited from their parents are chemically linked to mental problem could help provide us with tools to treat some very serious psychological conditions.

Meanwhile on a slightly lighter note – Tryptophan, a chemical the body uses to manufacture the happiness molecule serotonin, is found in high levels in 85% cocoa chocolate (so is serotonin but sadly it can not cross our blood-brain barrier whereas tryptophan can). So after enduring all this scientific stuff why not treat yourself to some pre-emptive anti-depression therapy. Time to open up the chocolate!

Chris Duggleby.

Chris Duggleby started his scientific career studying Bacteriology and Virology at the Manchester University Medical School. From there he went on to spend over 35 in the chemicals and oil industries which included setting up a polymers research and development group in Geneva, Switzerland for a major international chemicals company. Following an MBA from Warwick University he went on to lead a number of international manufacturing and marketing operations in the Chemicals, Plastics and Oil industries. This included being the founding President of Formosa BP Chemicals Corporation in Asia. His work involved living and working in Europe, Asia, the USA, the Middle East, and Russia. More recently he was invited to take on a senior leadership position in the Audit Department of the BP International Oil Group. Here he used his global change and risk management experience to help the group reshape its management structures and processes following a major environmental disaster in the Gulf of Mexico. He has now retired to focus on writing about risk management and producing music in his VALIUMM studios. If you are interested in risk management check out his RiskTuition.com or BizChangers.com (management of change) sites. He has also recently launched the JointVentureRisk.com site.

If you found this article interesting please consider taking a look at some of his other recent reports on similar subjects.

Just click on the titles below:

…starting with some more serious stuff:

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13th March 2016 Bugs Evolve That Can Eat PET Plastics Used In Bottles And Textiles

3rd March 2016 Using Gene Drives To Change Mosquito Sex In Fight Against Zika, Dengue and Malaria

1st March 2016 Ladies – upto half a satisfying sexual event per month but risk of side effects from “Pink Viagra” Flibanserin (“Addyi”)

14th Feb 2016 Breast Cancer – How Blind People Use Their Enhanced Tactile Sensitivity to Save the Lives Of Women With Tumours

3rd Feb 2016 Zika Infection Spread By Sex In Dallas – Earlier Sexual Transmission In Colorado – Detailed Symptoms 

1st Feb 2016 Sexual Competition Between Women – Ovulation Can Be Seen In The Face

31st Jan 2016  Bed Bugs – Insecticide Resistance – Arbovirus Transmission – Zika and Microcephy

19th Jan 2016 ZIKA Virus Epidemic  – Health Warning – Pregnant women should postpone travel to affected areas – Including Brazil 

17th Jan 2016 Bubonic Plague Special – Lice – Hosts for The Black Death Bug

13th Jan 2016 Kill Head Lice In A Day With The Newly Developed Plasma Nitcomb From The German Fraunhofer Institute

8th Jan 2016 Cancer from Handbags, Shoes and Gloves – Allergic Reactions to Jewellery – German Institute Identifies Excessive Chromium 6 and Nickel Levels

26th July 2015 Poison in your Washing Machine: Allergic Contact Dermatitis from Laundry Detergents, Softeners, Conditioners and Whiteners

17th October 2015: Health Risk: Vitamin and antioxidant supplements help cancer cells become malignant – latest research from Texas

31st May 2015: German Concern about Potentially Carcinogenic Aromatic Hydrocarbons in Cosmetics  

29th December 2012: Spreading diarrhea and vomit through the washing machine– The Norovirus propagator in our kitchen

and here are some fun related articles:

19th March 2016: Joggers – How To Stop Dogs Chasing You – Research Into New Pet Friendly Technology

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4th March 2016: Dachau Industry Park Evolves From Concentration Camp To Nudist Wellness Club (Brothel)

21st June 2015: Bio-undies: Guilt free Passion with ‘Easy Emma’ and ‘Loose Harry’and Getting Rid of Garden Snails with Rent-a-Duck

4th March 2015: Hamburg Reeperbahn (St. Pauli): Germans install walls that urinate on passers-by

17th April 2014: Niche On-line Dating Services (Specialities: Herpes, Thrush and Genital Warts)

18th March 2014: Germany and Finland Joint Investigation: New Case of Sexual Cannibalism Including Self-mutilation (Castration) During Intercourse.

18th August 2012: How Bavarians and Austrians use their middle finger – Fingerhakeln: a men-only sport (did Arnold Schwarzenegger start training this way?).

You can also find some of my more humorous reports in the Alpine Press section of this site using the link here.