What Is the Connection Between Depression and Stress?

The more you study your psychology the more you realize that you are really a slave to the chemical reactions taking place in your brain. If you’re stressed, it’s probably because you’ve had a recent influx of norepinephrine, cortisol and adrenaline. If you’re happy, you’re probably enjoying an influx of oxytocin and serotonin. Creative? That would be anandamide and probably some GABA to help you relax. Switched on and focused? Hello dopamine and acetylcholine!

So true is this that some people will even try to ‘hack’ their neurotransmitters by increasing the desirable states and suppressing the negative ones. Consuming 5-HTP and foods containing tryptophan for instance can improve the mood seeing as they are the precursors to serotonin. If you’re in a good or bad mood, it might just be to do with what you had for lunch!

BrainUnfortunately though, it happens that some people have naturally more desirable levels of neurotransmitters than others. And what’s more, various factors in our lifestyles can often lead to unwanted changes in the chemical makeup of our brain that cause problems – problems such as depression and stress.

It’s not quite so easy to ‘fix’ such an imbalance either. As much as a ‘biohacker’ might try to gloss over this point, neurotransmitters are closely linked to one another and raising one will often lead to an increase in others. Dopamine for instance can be converted into norepinephrine, while opposite neurotransmitters can be released to help combat any extreme increase one way or another.

The Neurochemistry of Depression and Stress

So what do depression and stress look like in the brain? They have some striking similarities but are also opposites in some ways.

Both depression and stress for instance exhibit decreases in the amount of serotonin in the brain (1). It would seem that an increase in cortisol (one of the stress hormones) might actually decrease brain 5-HT production which is a precursor to serotonin.

Serotonin is known as a ‘happiness’ hormone and leads to feelings of elation and anticipation, while at the same time reducing pain and other stress hormones. Low serotonin then is correlated with both stress and depression which is why we often feel ‘low’ in the face of chronic stress.

But there are differences here as well. For instance, acute stress in particular causes the release of norepinephrine, adrenaline and dopamine. These are chemicals that make us feel more alert, switched on and sensitive to our surroundings but they also elevate the heart rate and make it difficult to relax.

Depression on the other hand tends to be associated with low dopamine and norepinephrine. This is because the continued release of these substances can eventually lead to ‘adrenal fatigue’. In other words, the body has been producing hormones designed to make us ‘go’ for too long and eventually burns out leaving us with low energy and reduced drive and focus.

This is why prolonged chronic stress can lead to depression. In the short term it reduces serotonin and in the longer term it leaves us exhausted and with diminished feelings of motivation, drive and satisfaction.

Stress has also been shown to increase the release of pro-inflammatory cytokines. This increases inflammation throughout the body which could potentially be helpful in a ‘fight or flight’ scenario by protecting injuries. Pro-inflammatory cytokines however can also cause brain inflammation which has been linked to brain fog and – you guessed it – depression.

What’s more, stress hormones have even been shown to lead to diminished brain plasticity, meaning that your learning can also be hampered by stressful events. In these ways, depression and stress become self-perpetuating.

How to Combat the Effects of Depression and Stress

If you find yourself in a situation where you are experiencing depression and stress, what’s the best way to combat it?

Often the best place to start is by removing the source of the stress. If you experience ongoing stressors then this will cause the release of cortisol, in turn reducing your production of serotonin and making it more difficult to overcome feelings of stress.

If your stressor is not so easy to simply ‘remove’ then other alternatives are to take a break from the stress (such as going on a long holiday) and/or to use cognitive behavioral therapy in order to help yourself react more healthily to stressful events. CBT looks at changing the way you interpret stress and the way you handle it psychologically, which in turn can make you more resilient against it and less likely to let it develop into depression.

Keith Hillman

Keith Hillman is a full time writer specializing in psychology as well as the broader health niche. He has a BSc degree in psychology from Surrey University, where he particularly focused on neuroscience and biological psychology. Since then, he has written countless articles on a range of topics within psychology for numerous of magazines and websites. He continues to be an avid reader of the latest studies and books on the subject, as well as self-development literature.