Depression: Is it linked to brain dysfunction?
Published 17 Jul 2021 • By Candice Salomé
Depression is a common condition. In the UK, 3 in 100 people are diagnosed with depression in any given week and it is estimated that around 20% of people aged 16 or over may currently be experiencing symptoms of depression. This mental illness is characterised by a persistent state of sadness, a loss of interest in life and activities, change in appetite, sleep and libido and can seriously impact a person's daily life.
But what happens in the brain of people affected by depression? Can depression be linked to brain dysfunction? How can we regulate our brain chemistry?
We tell you everything in our article!
Depression can be seen as a generalised breakdown affecting several areas: emotions, thoughts and behaviours; during which certain brain functions are altered, causing disturbances.
The pleasure and adaptation mechanisms are the most affected, meaning that it can become difficult to get motivated and moving. It can also be hard to think positively about oneself and others, and guilt may arise from not being able to cope with all these new emotions.
The psychological causes of depression always lead to a chemical imbalance that is responsible for these various symptoms.
What is the link between depression and chemical imbalance in the brain?
Depression is caused by an imbalance in the brain system. This is caused by an imbalance in the functioning of certain neurotransmitters. Neurotransmitters are molecules that allow the passage of information from one neuron to another.
In depression, the neurotransmitters that are dysfunctional include:
- Serotonin, whose role is to balance sleep, mood and appetite,
- Norepinephrine, whose role is to manage attention and sleep,
- Dopamine, which is used to regulate mood and motivation,
- gamma-Aminobutyric acid (GABA), whose role is to facilitate relaxation.
In general, when these neurotransmitters are well regulated, everything goes well. However, if there is a small imbalance, either when too few or too many neurotransmitters are present, things may go haywire, and the symptoms of depression appear.
This phenomenon can have different consequences. On the one hand, a slowing down of the brain can be observed and symptoms such as a drop in energy, attention and concentration problems, and an inability to make decisions emerge.
On the other hand, activity is accelerated in one part of the brain, which results in insomnia, increased anxiety, rumination and the activation of a chain of negative thoughts.
Can hormones play a role in depression?
Another internal factor could trigger depression: hormonal imbalance. This imbalance is also relevant to postpartum depression.
In fact, an insufficient level of oxytocin, a hormone secreted by the pituitary gland and released during breastfeeding, can be behind certain cases of post-partum depression.
In addition, when cortisol is disrupted, glucocorticoid levels increase, unbalancing and blocking neurotransmitters located in the hippocampus (a brain structure that plays a fundamental role in learning and memory). When this happens, mood disorders can be triggered.
The same is true when the thyroid gland malfunctions. Thyroid hormones play a role in most of our bodily functions. When the thyroid does not produce enough hormone, it is called hypothyroidism. The result is a general slowing down of the body's metabolism, causing significant fatigue and, very often, weight gain.
How to regulate brain chemistry?
Antidepressants, as their name suggests, treat depression. They work in the brain by altering the chemical messages in the neurons and relieve the symptoms of depression.
Antidepressants must be taken continuously for 3 to 6 months or more to be effective. This treatment can improve mood, and both relieve and stabilise the symptoms of depression. However, the benefits are not immediate. Patients usually feel an improvement after 3 or 4 weeks of continuous treatment.
Antidepressants are not physically addictive. However, abruptly stopping them exposes the patient to significant side effects such as insomnia, anxiety, irritability, etc. Discontinuation of treatment must therefore be done gradually and be planned by a doctor.
There are about twenty antidepressant molecules. These molecules all have the same effectiveness, but some act on anxiety, others on fatigue. The doctor may therefore decide, after a few weeks, to modify the patient's treatment.
The different classes of antidepressants are as follows:
- Selective serotonin reuptake inhibitors (SSRIs): these are prescribed for mild to moderate depression,
- Serotonin and norepinephrine reuptake inhibitors (SNRIs): their role is to increase the concentration of serotonin and norepinephrine in certain areas of the brain,
- Tricyclic antidepressants (TCAs) are used to correct and elevate depressed moods until the normal state is reached again. These are suitable for severe depression.
- Monoamine oxidase inhibitors (MAOIs): these are prescribed when depression is resistant to other treatments.
It is important to combine drug treatments with counselling or other psychological follow-up in order to prevent relapses of depression by working to understand and eliminate the root cause.
Serotonin and tryptophan are directly linked - in fact, tryptophan is converted into the neurotransmitter serotonin in the brain. Tryptophan is an amino acid, a constituent of proteins, which cannot be manufactured by the body and must be supplied each day through our diet.
Foods rich in tryptophan include eggs, dairy products, fish, meat, brown rice, seeds (especially pumpkin and chia) and bananas. It is therefore important to consume them regularly.
Magnesium is also involved in the production of serotonin. It is found in dark chocolate, almonds, bananas and spinach.
Physical activity helps to reduce anxiety and depression. This is because of the chemical phenomena and substances released in the brain after a sports session.
During a workout, our brain secretes adrenaline, dopamine, norepinephrine and cortisol, resulting in widespread stimulation and an instant feeling of euphoria.
To feel the benefits, we should do at least one hour of physical activity per week.
- Mental health statistics: depression, Mental Health Foundation
- Les activités physiques, Fédération pour la recherche sur le cerveau
- Antidépresseur : comment fonctionne ce médicament ?, Je vais mieux, merci
- Les causes biologiques de la dépression : dérèglement de sérotonine, dopamine..., Futura Santé
- La dépression, une affaire de chimie, Les Echos
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