Kyle MacDonald: What causes depression?

One of the strongest predictors of depression is childhood emotional neglect and/or abuse. Photo / Getty

Q: I've recently been diagnosed with depression, and the medication I've been given seems to have helped. But what causes depression? There seems to be no clear answer and so many theories.

A: Despite what some might want to tell you, there is no one cause. Depression is what we call "over-determined", meaning there are many potential causes, and most people will have some of them, but from individual to individual the path to depression can look quite different.

It's also true that from person to person what we might label as depression may look like an entirely different illness.

And though there technically are different diagnoses under what we loosely call "depression" even two people who are both diagnosed with "Major Depressive Disorder" might experience some aspects the same, and some differently.

So yes, it is complicated.

While there is no conclusive "gene" for depression, it does seem to be hereditary to some degree, in that if a parent has experienced depression you are more likely to experience it yourself. However that's no guarantee.

And it's also true that we learn through our childhood from what we see, so even if there is some genetic aspect, it's also potentially learned from our environment.

Many people will tell you it's a brain disease. It is not. There is no doubt your brain, and its chemical messengers – neurotransmitters such as serotonin - the ones your medication likely targets - are involved. But depression is not caused by something suddenly going wrong with your brain. The chemical imbalances are the outcome, or possibly for some a significant contributing factor - not the sole cause.

Burnout, isolation and disconnection in our day-to-day life can certainly look like a strong cause, but not everyone who goes through those experiences depression, and there is some research that what we are recognising more and more as burnout may very well be a different "thing".

One of the strongest predictors - although again, not a cause on its own, nor something everyone who experiences depression will have experienced - is childhood emotional neglect and/or physical, sexual or emotional abuse.

Most people get that abuse in childhood can lead to later emotional struggles, but neglect can be harder to define and pin down because it can be hard to know if something wasn't there.

Neglect can look like a happy family, where all that is needed is provided, while we actually have an emotionally distant, cool or disinterested relationship with our parents. It can be very subtle.

And though these childhood experiences aren't "the" cause, they are a strong factor with studies showing around 50 per cent of people who develop depression will have experienced abuse and/or neglect in their childhood.

It does also have a direct impact on severity, that is to say, if abuse and neglect is in your background, and you develop depression, you're likely to experience it more severely.

In short, the predisposition for depression is likely to be part of your makeup, but things need to happen for that to be expressed, and the quality of your childhood is likely to have a direct impact on how severe the impact will be for you.

On the other hand, even with a predisposition, if your childhood was largely good enough and you have developed a flexible response to life challenges, you may have the predisposition and it will never be expressed, or if so only mildly (relatively speaking).

None of this changes the things that work: medication, healthy living, talking to a professional if you need to. And often therapy can help you develop a validating, compassionate story for yourself about why you experience depression.

Because while it's hard to be definitive about the general reasons, it's incredibly helpful if you can learn something useful about your personal causes.

Where to get help:

If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.

Or if you need to talk to someone else:
Depression helpline: 0800 111 757 or text 4202
Lifeline: Call 0800 543 354 or text 4357 (HELP)
Suicide Crisis Helpline: Call 0508 828 865 (0508 TAUTOKO)
Need to talk? Call or text 1737
Women's Refuge: Free national crisis line operates 24/7 - 0800 refuge or 0800 733 843 www.womensrefuge.org.nz
Shine, free national helpline 9am- 11pm every day - 0508 744 633 www.2shine.org.nz
It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz
Shakti: Providing specialist cultural services for African, Asian and middle eastern women and their children. Crisis line 24/7 0800 742 584