Depression: A Plain-English Guide

Reading time: about 5 minutes. General education only, not medical advice.

What is it?

Depression is a common and serious health condition. It is more than feeling sad or having a bad week. With depression, a low mood or loss of interest lasts most of the day, nearly every day, for at least two weeks. It affects how you feel, think, sleep, eat and manage daily life.

Depression is not a sign of weakness, and you can't just "snap out of it." It can happen to anyone, at any age. It often comes from a mix of things: genes, life events, stress, other health problems and changes in the brain. The good news is that depression is treatable, and most people can feel better with the right help.

There are different kinds. Major depression is the most common. Persistent depressive disorder is a milder low mood that lasts two years or more. Depression can also happen during or after pregnancy (perinatal depression) or with the seasons (seasonal affective disorder).

Common signs and experiences

  • feeling sad, empty, anxious or hopeless
  • losing interest or pleasure in things you used to enjoy
  • feeling tired or low on energy
  • sleeping too much or too little
  • eating more or less than usual, or weight changes
  • feeling worthless or guilty
  • trouble concentrating, remembering or making decisions
  • moving or talking more slowly, or feeling restless
  • aches, pains or stomach problems with no clear cause
  • thoughts of death or suicide

Not everyone has every sign. Depression can look different in children, teens and older adults. For example, teens may seem irritable rather than sad.

How it's diagnosed

A doctor or mental health professional asks about your mood, sleep, energy and how long things have been hard. They may use a short questionnaire. A physical exam or blood tests can rule out other causes, such as thyroid problems, low vitamin levels or side effects from medicines.

Usual treatments today

  • Talking therapy. Cognitive behavioural therapy (CBT), interpersonal therapy and other therapies help many people. For mild depression, therapy or guided self-help is often tried first.
  • Medication. Antidepressants can help, especially for moderate or severe depression. They usually take a few weeks to work. Side effects are possible, and it can take time to find the right one. Don't stop them suddenly without talking to your doctor.
  • Lifestyle support. Regular activity, sleep routines and staying connected with people can support recovery.
  • Other options. For depression that doesn't improve, doctors may suggest treatments such as brain stimulation (for example ECT or TMS).

Where metabolic health fits in

Metabolism is how the body turns food into energy. Mitochondria are tiny parts inside our cells that make most of that energy.

Researchers are looking at metabolism and depression for several reasons:

  • Depression is more common in people with conditions like obesity, type 2 diabetes and heart disease, and the link seems to go both ways.
  • Inflammation (the body's defence response, which can stay switched on at a low level) and insulin resistance (when the body struggles to use insulin) have been linked with depression in some people.
  • Some studies suggest that energy use in brain cells, including mitochondria, may be different in depression.

Diet is one area being tested. In the SMILES trial in Australia, adults with depression who got support from a dietitian to eat a healthier, Mediterranean-style diet improved more than a group who got social support instead. It was a small, 12-week trial, and people knew which group they were in. Scientists are also studying ketogenic diets, exercise and the gut, but most of that work is early.

This is emerging research, not established treatment, and it is not a cure. Diet and lifestyle are being studied as additions to usual care, not replacements for therapy or medication.

Safety first. Do not start a ketogenic or other therapeutic diet on your own. These diets can change how some medicines work, including mood stabilisers and diabetes medicines. They can cause side effects, and they may not be safe for everyone, for example during pregnancy or with some kidney, liver or eating problems. In studies, people were followed by doctors and dietitians.

When to get help

See a doctor if a low mood or loss of interest lasts more than two weeks, or is making daily life hard. Get help right away if you are thinking about hurting yourself or ending your life.

  • US: call or text 988 (Suicide & Crisis Lifeline), or chat at 988lifeline.org.
  • Emergency: call 911 or go to the nearest emergency room.
  • Outside the US: contact your local emergency number.

Research posts on this condition are coming soon.

Disclaimer

This page is for general education only. It is not medical advice, and it is not a diagnosis or treatment plan for anyone. We are not able to review anyone's situation. Metabolic psychiatry is a young field, and research summaries here may be incomplete or out of date, so please read the original sources. Always talk with your own doctor, psychiatrist or other qualified clinician before changing a diet, starting a supplement, or starting, stopping or changing any medication. Stopping psychiatric medication suddenly can be dangerous. Read the full disclaimer.

If you are in crisis in the US, call or text 988. For emergencies, call 911.

Sources