Mental and Cognitive Health

Your Brain Is a Physical Organ

Think of the brain like any other organ in your body. Your heart gets stronger when you exercise it. It gets weaker when you neglect it. Your brain works exactly the same way. The choices you make daily are either building it or quietly wearing it down.

The World Health Organization describes mental health not as simply being free of illness, but as a state of wellbeing. It is a state of mental wellbeing that lets people cope with the stresses of life. It lets them realize their abilities, learn well and work well, and contribute to their community.

That is a lot to ask for. And it can be reached. But it means treating the brain the way it deserves. As the physical organ it is.

Two People, Two Different Minds

Rachel and Ade are not real patients. They were written for this guide. Nothing that follows is a case history, a diagnosis, or a prediction about any real person.

Picture two people, Rachel and Ade. They are the same age, live in the same city, and have about the same amount to deal with each day.

Rachel sleeps six hours most nights. She eats quickly and at odd hours, usually standing up. She has not exercised in two years, though she still thinks of herself as someone who will start again. The phone is the last thing at night and the first thing in the morning, and she could not say when that began. She rarely sees friends now, which happened by drift rather than by decision. She tells herself she is fine, and she is not lying.

But she notices things. She forgets where she put things more than she used to. She finds it harder to concentrate. She feels flat most afternoons. Small frustrations feel bigger than they should. She has a vague, nagging sense that something is slightly off. She cannot name it. She does not know where to look.

Ade sleeps seven and a half hours every night. He eats breakfast with protein and vegetables, the same one most days, because deciding is the part he finds hard. He walks for 20 minutes daily, a habit that began when he had a dog and outlived the dog. He has two or three people he truly talks to about his life. He is not free from stress. He has hard days. But he recovers from them. He comes back to himself. His thinking is sharp. His mood is steady. He feels, on most days, genuinely well.

These are two people carrying a similar weekly load, and it would be wrong to say their habits are the whole difference between them. Mental health is shaped by many things nobody chooses: genes, past experience, illness, medicines, money, safety, loneliness, and plain chance.

What can fairly be said is simpler. The brain is a physical organ, and like the heart it responds to sleep, movement, food and connection. Those things are not a cure, and needing more than them is not a failure. But they are real, and they are among the parts most open to change.

That does not mean anyone who becomes unwell brought it on themselves. People fall ill while doing everything right.

You are not stuck with the brain you have today. Every day, the way you live is quietly rebuilding it.

What Mental Health Actually Means

Mental health is not just about being free of depression or anxiety. It is a range, and every person sits somewhere on it.

At one end is thriving, which means clear thinking, a steady mood, the ability to handle hard times without falling apart, real connection with other people, and a sense of purpose. At the other end is serious mental illness, meaning conditions that badly disrupt daily life and need professional care.

Most people spend most of their lives somewhere in the middle, neither thriving nor seriously ill. Just managing. Getting through. Functioning, but not flourishing.

The goal of this article is not to treat serious mental illness. That needs professional support, and this article is not a replacement for it. The goal is to explain the biology underneath everyday mental health. What the brain needs to work at its best. And what quietly wears it down when those needs are not met.

How the Brain Changes Throughout Life

For a long time, scientists believed the brain was fixed, and that by adulthood the brain you had was the brain you kept. No new cells, no new connections, and nothing ahead but a slow decline. That belief has now been shown to be wrong.

Your brain is not fixed. It can change. Scientists call this neuroplasticity, the brain’s power to change. Its shape, and the way it works, shift with what you do and what happens to you.

Think of the brain like a living town. Roads are always being built. Old roads that nobody uses slowly close. New buildings go up. Old ones come down. The town changes shape based on what happens in it. Your brain does the same.

Repeat something often enough and it reshapes the connections inside: every skill you practice, every habit you keep, every thought you return to. Most passing moments leave no mark at all, and the ones you come back to are the ones that do. This works in both directions. Healthy habits build stronger pathways, while repeated stress, loneliness and poor habits slowly weaken them.

The finding that matters most here is simple. It is never too late. The brain keeps its ability to change and grow throughout life. Whether the adult brain also grows entirely new cells is one of the liveliest arguments in brain science right now. Some teams find new cells still being born into old age in the hippocampus, the brain’s memory and learning center. Others, using different methods on different tissue, find almost none after childhood. A commentary in Science Translational Medicine laid out both sides. The two findings came out within weeks of each other. The question is still open.

Here is what is not in dispute, and it is the part that matters for you. The connections between the cells you already have are reshaped constantly. How fast that happens depends on how you live. Exercise supports some of that reshaping. Long stress works against parts of it. Long stress also makes the brain quicker to learn fear. Sleep is where much of the reorganizing happens. Your daily choices are shaping the physical structure of your brain.

The story so far. Rachel would not describe her life as stressful. She would call it busy. That distinction matters less than it sounds. The brain responds to sustained pressure the same way, whichever word you use.

What Stress Does to the Brain Over Time

Stress is not just a feeling. It is a real, physical event inside the brain.

When you feel stress, your brain switches on the hypothalamus. The hypothalamus is a small part deep in the brain. Think of it as the brain’s alarm button. The moment it senses danger, it sets off a wave of chemical signals through the body.

Two of those chemicals matter most here. The first is adrenaline. Adrenaline is the fast one. It hits in a second. It makes your heart pound, your breath quicken, and your body ready to run or fight. Then it fades within minutes. The second is cortisol. Cortisol is the slow one. It is a hormone you need every day. It rises in the morning and falls at night. It helps run your energy, your blood pressure, and your defense against illness. Under pressure it climbs and keeps the body on alert. Think of it this way. Adrenaline is the sudden sprint. Cortisol is the long shift that follows.

In short bursts, all of this is useful. It protects you. But let the alarm keep firing, week after week, and it starts to harm the very brain it was built to protect.

Research in Nature Reviews Neuroscience is clear about the cost. Long stress weakens how the prefrontal cortex works. It can also change the wiring running through it. The prefrontal cortex is the part most involved in careful planning and self-control. It is the part that stays calm, weighs things up, and stops you from doing something rash. Think of it as the careful driver who slows down and looks both ways before moving. Long stress wears down how well that driver does the job.

At the same time, long stress leaves the amygdala more easily triggered. The amygdala helps spot threats. It also picks out what matters emotionally, the good as well as the bad. It is the part that shouts “danger!” before you have even had time to think. Think of it as a smoke alarm that goes off at the smallest hint of smoke. Long-term stress makes this alarm bigger and louder.

So stress pulls the brain in two wrong directions at once. The calm, careful driver gets smaller. The blaring alarm gets bigger. Clear thinking gets harder. Fear and upset come faster. This is not a weakness in you. It is biology. It is what stress does to a physical organ when that organ does not get the chance to recover.

The good news is that the brain can recover and adapt. Neuroplasticity works both ways. With the right care, the calm driver can work better again. The alarm can settle down. Those right conditions are exactly what this article covers.

The Connection Between the Gut and the Brain

This is one of the most surprising findings in recent brain science. Your gut and your brain are in constant conversation, joined by a vast network of nerves, hormones, and chemical signals. Scientists call this the gut-brain axis.

Think of the gut-brain axis as a two-way phone line between your stomach and your mind. The calls go both ways. What happens in your gut affects how you feel in your head. And what happens in your head affects what happens in your gut.

Here is the surprising part. Serotonin is a chemical messenger, one of those most tied to feeling steady, calm and well, and in the brain it helps keep mood level. More than 90 percent of it is made in the gut rather than the brain. It is produced by enterochromaffin cells, special cells in the gut lining, and how much gets made is shaped by the tiny living things, or microbes, that live there. Most people think of serotonin as a brain chemical. It is one. But your gut makes far more of it than your brain does.

Here is the part that often gets told wrong. The serotonin made in your gut stays in your gut. It cannot cross into the brain. Your brain makes its own supply.

The gut still shapes your mood, but through other routes. It supplies the raw material your brain needs to build serotonin. It sends signals up the vagus nerve, the main cable running from gut to brainstem. And it shapes the low level of inflammation, the body’s repair response, which affects mood too. Research published in Current Opinion in Psychiatry looked at the gut microbiome. That is the crowd of tiny living things in your gut. It found links between what lives there and rates of depression and anxiety. Much of that work watches people without testing anything. Some of it is done in animals. So the link is real and the cause is not settled.

What you eat affects your microbiome. Your microbiome affects the signals and raw materials your brain receives. Those affect your mood. The food on your plate and the feelings in your mind are more directly connected than most people ever realize.

How Sleep Shapes Mental Health

Sleep is when the brain works through the emotional experiences of the day.

REM sleep is the dreaming stage, when your eyes move quickly under your closed eyelids. During it, the brain goes back over the feelings tied to your day. Researchers think this helps it sort and settle them, though how far the effect goes is still being worked out.

Think of it like watching a film you found frightening the first time. The second time, knowing what happens, it is less intense. The third time, even less so. Something similar may happen with hard memories. The memory stays. The sharpness of it can soften.

It is one reason a problem that felt unbearable at midnight can feel more manageable in the morning. It is one reason among several. Time, rest, and daylight all help too.

When sleep is cut short, this process is interrupted. The emotional weight of hard experiences does not get processed. It carries over into the next day at full force. And the next. And the next.

Health authorities worldwide list poor sleep as one of the main things that lead to poor mental health. Poor sleep and poor mental health feed each other in a circle. Each one makes the other worse. Breaking that circle sometimes starts with sleep. Sometimes it starts with treating the depression, the anxiety, the pain, or the sleep disorder underneath. Which comes first depends on what is driving it.

How Movement Changes the Brain

Movement is one of the most reliable tools for mental health available to anyone, and it needs no prescription, no booking and no money.

When you move your body, your brain releases a protein called BDNF. BDNF stands for brain-derived neurotrophic factor. That name is hard to say, so here is the simple version. Think of BDNF as the upkeep budget for your brain. It does not build new rooms. It keeps the ones you have in good repair. It keeps the cells you already have healthy. It helps them adapt, and it strengthens the connections between them. Movement is linked to more of it. How much more depends on the kind of exercise, how hard it is, how long it lasts, and who you are.

A Lancet Psychiatry study reviewed data from 1.2 million people. Those who moved regularly reported about 43 percent fewer days of poor mental health each month. Put another way, for every 10 bad days reported by people who did not move regularly, those who did reported about 6. That means fewer days feeling low, fewer days lost to worry, and fewer days when the world feels heavier than it should.

The same study found something that cuts against the obvious conclusion. More was not always better. The best results came from sessions of about 30 to 60 minutes, three to five times a week. People exercising for longer than 90 minutes at a time, or more than 23 times a month, reported worse mental health than that.

All of it was measured at a single point in time, so it shows a link rather than proof. To show that moving is what caused the change, you would need a different kind of study.

Hard exercise pushes cortisol up for a while, which is normal. Over weeks, regular movement helps your body handle stress better, which shows up as less worry, better mood and better sleep. It also raises endorphins, the brain’s natural pain-easing, pleasure-giving chemicals. Think of them as your body’s own built-in mood medicine, released by movement, available to everyone, and free.

The official advice doctors follow, including NICE guidance in the United Kingdom, lists structured exercise programs among the treatments for less severe depression. Sometimes on their own. Sometimes alongside other care. What suits a person depends on how severe things are, what they have tried, and what they will keep doing.

The story so far. Ade has two or three people he genuinely talks to. Rachel has a full contact list and almost no one she calls. That gap turns out to matter more for the brain than almost anyone expects.

The Role of Social Connection in Brain Health

The brain was not built for loneliness. It was built for connection. Time with other people is not just pleasant. Your brain needs it to stay healthy.

Warm contact with another person is tied to oxytocin, a hormone sometimes called the bonding chemical. Think of it as the brain’s warm handshake. It plays a part in trust and feeling safe, and in calming the body. What it does depends on the person, the relationship, and the moment. Some encounters comfort you. Some do the opposite.

When a person is cut off from others for a long time, the brain treats it as danger. The alarm systems switch on. Cortisol, the slow stress chemical, rises. Low-grade inflammation rises. The prefrontal cortex, the careful driver, becomes less active. The amygdala, the blaring alarm, becomes more active. Thinking turns more guarded, more negative and more fearful.

Research published in PLOS Medicine gathered many different measures of social relationships and compared how strongly each was tied to living longer. Weak social ties came out at a size often likened to smoking up to 15 cigarettes a day. That is a comparison of how large the two effects are, not a claim that they harm the body in the same way. These studies also followed people rather than testing a treatment, so they show a link rather than proof that weak ties alone shorten life.

Three things get mixed up here, and they are not the same. Loneliness is the pain of having less real connection than you want. Social isolation is having few people around you at all. Solitude is time spent alone, which for many people is restful and welcome. Wanting time by yourself is not a health problem. Long, unwanted loneliness is.

What Nutrition Does to the Mind

Your brain is only about 2 percent of your body weight, yet it uses about 20 percent of your daily energy. It is the hungriest organ in the body, and what you feed it matters a great deal.

Some of what you eat is burned for energy. Some of it becomes the body itself.

Think of a house built from brick. You cannot burn brick to heat the room. But it is what the walls are made of, and there is no house without it.

Omega-3 is that second kind of food. It is a family of fats, and the one the others are built from is called alpha-linolenic acid, which your body cannot make at all. It has to come from what you eat.

Two members of that family, EPA and DHA, come mainly from oily fish such as salmon, mackerel and sardines. DHA is the brick in this comparison, forming part of the walls of your brain cells. And a house needs the right brick rather than an endless delivery of it.

Walnuts, flaxseed and chia give you the plant form, but your body turns only a small share of it into EPA and DHA, so they are not a straight swap for fish.

Lower omega-3 levels have been linked to depression in some studies. Whether taking more prevents or treats depression is not clear. Studies point different ways. So treat oily fish as good food. It is not a guarantee.

Steady blood sugar also matters a lot for the mind. Blood sugar rising after a meal is normal. Refined carbohydrates and sugary foods tend to send it up faster, and for some people the fall afterwards is noticeable. Refined just means the goodness and fiber have been stripped out.

How much that affects mood varies. A genuine sugar low, the kind people with diabetes know, clearly affects mood and concentration. The ordinary dips most people feel after a heavy lunch are a smaller thing. The brain runs best on a steady supply of glucose, the sugar your blood carries. Meals built around whole foods deliver it more evenly.

A study published in BMC Medicine followed nearly 27,000 adults for around five years. Those eating more ultra-processed food were more likely to develop signs of depression over that time. Ultra-processed food means food made in a factory from things you would not cook with at home, and packaged snacks, soda, instant noodles and prepared meals are all examples.

Three things are worth knowing about that result. The study recorded what people chose to eat rather than assigning anyone a diet. It counted signs of depression measured by a questionnaire, not depression diagnosed by a doctor. And within the ultra-processed category, the clearest links were to sugary drinks and to sauces and added fats, rather than to every such food equally. So it shows a link over years. It does not tell you how today’s lunch will make you feel tomorrow.

The story so far. Rachel does not need a different brain. Ordinary changes would help her. None of them need money, equipment, or permission. If the tiredness and the foggy thinking carried on through all of them, she would want a doctor to look for something else. Thyroid trouble, low iron, medication effects and several other things can look exactly like this.

How to Protect Your Brain Every Day

Sleep seven to nine hours every night.

Everything else rests on this. Every other step works better when sleep is enough. Protecting sleep is protecting the brain.

Move your body regularly.

Walking, swimming, cycling and dancing all count. The World Health Organization advises adults to aim for at least 150 minutes of moderate movement across the week. If you are starting from very little, begin with what you can manage, because any movement is better than none.

Eat for your brain.

Include oily fish regularly, within the guidance where you live. Eat plenty of vegetables of different colors. Choose whole-grain carbs over refined ones. Cut back on ultra-processed food, the packaged, factory-made kind. Protein alongside your carbohydrates helps keep blood sugar steadier through the day.

Put time into your relationships.

Be there for the people close to you. Reach out to them. Belong somewhere. Even brief, real moments with others help.

Take action on stress.

Waiting for stress to pass is not a plan. Regular movement, enough sleep, and honest talk with someone you trust all help the body handle it, and so do time outdoors and slow breathing.

When stress is severe, the right help depends on what is causing it. That might be a doctor or a therapist. It might be a change at work, help with money, or protection from someone who is not safe to be around. Sometimes it is medication, and sometimes it is emergency care.

Protect your prefrontal cortex.

It is your brain’s wisest part. Long-term lack of sleep, long-term stress, and heavy alcohol use all work against it. Everything that supports your overall health supports it.

Keep learning.

New experiences and learning spark new connections in the brain. Learning a new skill, reading widely, playing an instrument, or studying something unfamiliar are all forms of brain exercise. The brain gets stronger with use.

Start here

Protect your sleep first, then add a 20-minute daily walk and one real conversation. Sleep, movement, and connection are three of the strongest things you can give your brain, and all three are free.

When to Seek Professional Help

This article covers the everyday basics of mental health. But it is not a replacement for professional care. Please speak to a healthcare professional if you are facing any of the following.

Some people have thoughts of harming themselves or ending their life but do not intend to act on them. That does not mean the thoughts should be ignored. Tell someone you trust and contact a doctor or mental health professional as soon as possible. A crisis line can also help you decide what to do next. If the thoughts become stronger, you make a plan, you have access to something you could use, or you feel unable to stay safe, use the emergency box above immediately.

Other things call for an appointment rather than emergency help. Book one if you have low mood that has lasted more than two weeks, worry that gets in the way of daily life, large unexplained changes in your appetite, sleep or behavior, or trouble coping at work, in relationships, or with everyday tasks.

Professional support is not just for when all else has failed. It is a tool, the same way you would see an expert to help a physical injury heal. Asking for it shows you know yourself and are being wise. It is never a sign of weakness.

Back to Rachel and Ade

Rachel cannot name what is wrong. That is the hardest place to begin from, and it is where a great many people are.

So be careful with this comparison. Ade is not proof that habits are the answer. Mental health is shaped by genes, by what has happened to a person, by money, by safety, by loneliness, by plain chance. Rachel did not choose most of what she is carrying.

What can be said is that sleep, movement, food and other people all have real effects on how a brain works. And all four are things she has some reach over.

Start with one. Most likely sleep, because it makes the other three easier.

And if she does all of it and still feels flat, that is not a failure of effort. That is information. It means something else is going on, and it means a doctor rather than a longer list.

Frequently Asked Questions

Is mental health really connected to physical health?

Yes. Completely, and they cannot be separated. Your brain is a physical organ. It is affected by what you eat, how you sleep, and whether you move. It is also affected by how much stress you carry and how connected you are to other people. Mental and physical health are not two separate things. They are the same system.

Can lifestyle changes actually help with depression and anxiety?

Often, yes, and the evidence behind that is solid. The official advice doctors follow lists structured exercise among the treatments for less severe depression, and better sleep, regular movement and real connection help many people. They do not help everyone equally, though, and some people need more than this. For moderate to severe depression and anxiety, professional support is needed as well. Lifestyle changes work best alongside professional care, not instead of it.

Why do I feel worse mentally when I sleep badly?

Because sleep is when your brain works through the emotional experiences of the day. During REM sleep, the emotional charge of hard experiences is slowly reduced. Without enough sleep, this does not happen. The emotional weight carries into the next day at full force. Poor sleep also raises cortisol and weakens the prefrontal cortex, making it harder to manage your emotions.

How does gut health affect mood?

Your gut makes more than 90 percent of the body’s serotonin, the chemical messenger tied to steady mood. That gut serotonin stays in the gut. It does not travel to the brain, and your brain makes its own. The gut still affects mood, through three routes. It takes in tryptophan from your food. Tryptophan is a building block the brain can use to make serotonin, though plenty happens in between. It sends signals up the vagus nerve. And it shapes the level of low-grade inflammation in the body. Eating a wide range of plant foods, including fermented foods, supports all three.

What is neuroplasticity and why does it matter?

Neuroplasticity means the brain can change its physical shape because of what you do and what happens to you. It means the brain you have today is not the brain you are stuck with. Every healthy habit you build, every skill you learn, every good experience you have, physically changes your brain. New connections form. Existing ones strengthen. It is never too late to improve the health and function of your brain.

When should I seek professional help for my mental health?

Some things need help the same day. Contact emergency services or a crisis line now if you are having thoughts of ending your life, if you have a plan or a way to carry one out, if you have recently tried, if you feel unable to stay safe, if you are having thoughts of seriously harming someone else, or if your thoughts feel frightening, confused, or not like your own.

Other things call for an appointment. Book one for low mood that has lasted more than two weeks, for worry that gets in the way of ordinary life, or for large unexplained changes in how you are coping. Getting help early is a tool rather than a last resort, and reaching for it is a sign of wisdom.

How do I know if it is stress or depression?

Often you cannot, and no single rule separates them cleanly. Depression can start after something painful that you can point to. Stress can carry on long after the cause has changed.

Some signals are worth watching. Depression tends to drain the enjoyment out of things that normally give it. It often changes sleep and appetite in a lasting way. It can bring a flat, heavy feeling. Stress feels wound up. Depression often feels the opposite.

If low mood has lasted more than two weeks, stop guessing and speak to a doctor. Go sooner if it is severe, if daily life is falling apart, or if you are having thoughts of harming yourself.

Can exercise replace my antidepressants?

No, and this is important. Movement is a genuine treatment for less severe depression, and it is recommended alongside other care. But it is not a swap for medication you have been prescribed. Stopping an antidepressant suddenly can cause real withdrawal effects. It can also let symptoms come back. If you want to cut down or stop, talk to the doctor who prescribed it. It is done slowly, with checks along the way. Start moving, and keep taking your medication while you work it out together.

Some things do not wait for the next appointment. A severe reaction, a rash or swelling, a sudden lift into agitation or racing thoughts, or a marked worsening of how you feel. Contact a doctor urgently if any of those appear.

Why do I feel anxious when nothing is wrong?

Because the alarm system does not need a real threat to fire. Anxiety has many roots. Genes, difficult experiences, illness or medicine, hormones, alcohol or other drugs, and poor sleep all feed into it, and so do situations that would make anyone uneasy. None of that is a failing on your part.

Brains also learn patterns, and a well-worn alarm fires more readily. That is the hopeful part. Patterns can be rebuilt by changing what you do each day. If anxiety is getting in the way of ordinary life, it responds well to treatment and is worth raising with a doctor.

How can I help someone I care about who is struggling?

Ask, listen, and stay. Most people do not need advice or solutions. They need someone who does not look away and does not disappear. Ask how they are doing and then be quiet long enough for a real answer. Keep inviting them out even when they say no. Withdrawal is part of what is happening to them. It is not a message about you. If you think they may be considering suicide, ask them directly. Asking does not plant the idea. It gives them permission to say it out loud.

Take any answer seriously. Listen without arguing. Where you can do it safely, help put distance between them and anything they might use to hurt themselves. Help them reach a doctor or a crisis line. And bring in another trusted person. Do not carry this alone. If the danger is immediate, call emergency services.

Stay with them if it is safe for you to do so. If it is not safe, get help. Leaving is the right move. You are not responsible for keeping another person alive on your own, and no one should ask that of you. Check in again once the crisis has passed.

Does social media affect mental health?

It depends heavily on how it is used. Using it to arrange real contact with people usually does no harm. Scrolling without joining in, especially late at night, is the pattern most often linked with lower mood. The studies mostly just watched what people did. Nobody was given a treatment to test. So they show a link, not proof of cause. Unhappy people may simply scroll more. What is not in doubt is the indirect route. Time spent scrolling at night takes sleep, and lost sleep affects mood directly.

Medical References

1. World Health Organization. (2025). Mental Health: Strengthening Our Response. https://www.who.int/news-room/fact-sheets/detail/mental-health-strengthening-our-response

2. Andreae LC. (2018). Adult Neurogenesis in Humans: Dogma Overturned, Again and Again? Science Translational Medicine. 10(436):eaat3893. https://doi.org/10.1126/scitranslmed.aat3893

3. Arnsten AFT. (2009). Stress Signaling Pathways That Impair Prefrontal Cortex Structure and Function. Nature Reviews Neuroscience. 10(6):410-422. https://doi.org/10.1038/nrn2648

4. Dash S, Clarke G, Berk M, Jacka FN. (2015). The Gut Microbiome and Diet in Psychiatry: Focus on Depression. Current Opinion in Psychiatry. 28(1):1-6. https://doi.org/10.1097/YCO.0000000000000117

5. Chekroud SR, Gueorguieva R, Zheutlin AB, et al. (2018). Association Between Physical Exercise and Mental Health in 1.2 Million Individuals in the USA Between 2011 and 2015: A Cross-Sectional Study. Lancet Psychiatry. 5(9):739-746. https://doi.org/10.1016/S2215-0366(18)30227-X

6. Holt-Lunstad J et al. (2010). Social Relationships and Mortality Risk: A Meta-Analytic Review. PLOS Medicine. 7(7):e1000316. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1000316

7. Adjibade M, Julia C, Alles B, et al. (2019). Prospective Association Between Ultra-Processed Food Consumption and Incident Depressive Symptoms in the French NutriNet-Sante Cohort. BMC Medicine. 17(1):78. https://doi.org/10.1186/s12916-019-1312-y

8. National Institute for Health and Care Excellence. (2022). Depression in Adults: Treatment and Management. NICE guideline NG222. https://www.nice.org.uk/guidance/ng222

9. National Institute of Mental Health. Frequently Asked Questions About Suicide. https://www.nimh.nih.gov/health/publications/suicide-faq

10. International Association for Suicide Prevention. Crisis Centers and Helplines. https://www.iasp.info/crisis-centres-helplines/

11. World Health Organization. (2020). WHO Guidelines on Physical Activity and Sedentary Behavior. https://www.who.int/publications/i/item/9789240015128