Brain chemistry is the network of chemical messages through which nerve cells communicate with each other, and through which mood, sleep, concentration and the feeling of pleasure and fear take shape. When someone describes their day as “without energy” or finds themselves anxious for no clear reason, part of the story is happening at the level of these tiny substances. In this guide you will get to know the most important neurotransmitters and hormones, the function of each, how drugs tamper with them, and what you can do to support their balance, with links to a detailed explanation of each substance.
What is brain chemistry?
The brain contains tens of billions of nerve cells, and a cell doesn’t touch its neighbor directly. Between them is a small gap called the synapse, crossed by chemical messages that the first cell releases for receptors on the second cell to pick up. These messages are the neurotransmitters; some excite the next cell and some calm it.
The important thing is that it isn’t about the “amount” of one substance rising or falling, but a balance between many systems working together: a system for reward, another for calming, a third for responding to danger, and a fourth for regulating the biological clock. Any change in one of them usually shows up in more than one aspect of your life.
Neurotransmitters and hormones: what is the difference?
A neurotransmitter works close by and fast, in fractions of a second, inside the synapse between two cells. A hormone, however, is secreted by a gland into the blood to reach distant organs, and its effect is slower and longer. Some substances play both roles; adrenaline and noradrenaline, for example, work as transmitters in the nervous system and as hormones secreted by the adrenal gland, and oxytocin is secreted into the blood and also works inside the brain.
The most important brain chemicals and the function of each
This table summarizes the substances the section covers, and each name leads you to its full page:
| The substance | Its type | Its main function |
|---|---|---|
| Dopamine | Neurotransmitter | Motivation, learning from reward and movement |
| Serotonin | Neurotransmitter | Regulating mood, sleep and appetite |
| GABA | Inhibitory neurotransmitter | Calming nerve activity; it is the brain’s “brakes” |
| Endorphins | Natural opioid peptides | Relieving pain and the feeling of comfort |
| Noradrenaline | Neurotransmitter and hormone | Alertness, attention and readiness for danger |
| Adrenaline | Hormone and transmitter | The fight-or-flight response: palpitations and faster breathing |
| Cortisol | Hormone | Managing stress and energy throughout the day |
| Oxytocin | Hormone and transmitter | Bonding, trust and closeness to others |
| Melatonin | Hormone | The night signal and setting sleep times |
How does brain chemistry affect mood, sleep and concentration?
There is no single “happiness hormone”, and no single substance responsible for depression or anxiety. Mood is the result of interaction between serotonin, dopamine, noradrenaline and others, along with factors that have nothing directly to do with chemistry, such as pressures, relationships, sleep and physical illnesses. That is why symptoms overlap a lot: lack of sleep raises stress, constant stress disturbs sleep, and the two together weaken concentration.
- Mood: disturbance of the serotonin and dopamine systems is linked to depression, but it is part of the picture, not the whole picture. Read about the symptoms of serotonin deficiency and the symptoms of dopamine deficiency.
- Anxiety: overactivity of the danger systems with weak calming, which is what the pages GABA and anxiety and Adrenaline and anxiety explain.
- Chronic stress: cortisol staying high for long periods affects sleep, weight and immunity, and its details are in The symptoms of high cortisol and Noradrenaline and stress.
- Sleep: light at night and staying up delay the release of melatonin, and in Melatonin and sleep you will find when the supplement helps and when it doesn’t.
Brain chemistry and addiction: why is stopping hard?
Almost all addictive substances raise dopamine in the reward circuit with a force that natural pleasures don’t reach. With repetition the brain adapts: the receptors’ sensitivity decreases, so the person needs a larger amount for the same feeling, and ordinary activities lose their shine. This adaptation is what makes stopping hard even with a sincere wish to do so, and the article Dopamine and addiction explains it in detail.
The mechanism differs according to the substance. Opioids such as heroin and tramadol occupy endorphin receptors, so the body stops relying on its natural painkiller (see Endorphins and addiction). Alcohol and sedatives strengthen the effect of GABA, which is why stopping them suddenly may be dangerous and need medical supervision, as the article GABA and addiction explains. Research on the role of oxytocin in treating addiction, however, is still at the experimental stage.
The good news is that the brain regains a large degree of its balance after stopping, even if this takes weeks or months. The first period, in which many feel flat and lose pleasure, is expected and usually temporary, and you will find what happens during it in The symptoms of dopamine withdrawal.
Can an imbalance in brain chemistry be measured with a blood test?
There is no routine blood or urine test that measures the level of serotonin or dopamine inside the brain and diagnoses depression or anxiety from it. What is measured in the blood reflects what is happening in the body more than what is happening in the synapses. That is why the psychiatrist relies on the interview, the medical history and the symptoms, and may order tests to rule out physical causes such as the thyroid or anemia. Some hormones such as cortisol, however, have specific tests that the doctor orders when a particular disease is suspected, not to measure everyday “stress”.
That is why you should be wary of offers that promise a test revealing a “deficiency of happiness hormones” and then sell you supplements to treat it; this idea is a misleading oversimplification of a far more complex science.
How do you support the balance of your brain chemistry naturally?
There is no magic recipe, but there are habits with a proven effect on the mood and stress systems:
- Regular physical activity: one of the strongest evidence-supported ways to improve mood and reduce anxiety.
- Sleep at fixed times: waking at one time and exposure to daylight in the morning regulate the biological clock.
- Dealing with stress: slow breathing and contact with people you trust calm the danger response.
- Balanced food: the amino acids from which the transmitters are made are present in ordinary food, and there is usually no need for special supplements.
- Staying away from drugs and excessive alcohol and caffeine: they raise mood temporarily and then leave it worse.
For practical details arranged by strength of evidence: How to increase dopamine, How to increase serotonin, How to increase endorphins, and How to lower cortisol.
When do you need a doctor?
If sadness, loss of pleasure, anxiety or sleep disturbance persists for more than two weeks and starts to affect your work and relationships, this is a good time for a psychological assessment. And if you use a substance and notice that you can’t stop despite your attempts, specialist help will save you a lot. And watch for a rare emergency: the appearance of confusion, high temperature, tremor and muscle spasms after starting a medicine that raises serotonin or combining more than one medicine; this may be serotonin syndrome and calls for calling the ambulance on 123.
At Riviera Life in Sheikh Zayed, consultants in psychiatry and addiction treatment assess each case in complete confidentiality, and the first consultation is free on +201507999722. You can also read more about mental illnesses or types of drugs.