Ana suffers from depression. She does not leave her house. She is anxious, does not concentrate and has no motivation to read, to watch a movie or read a book. She is not even moved by her idols, or by a concert or a photo. She does not have the strength to do anything she likes. Nothing.
She has lost sexual desire and appetite. Her insomnia is rampant, she can not rest, her mind and body are exhausted. The emptiness, the sadness, and the disappointment are so deep that they become somatized. They become physiological in the form of stomach problems, chills, pains… Her hands and legs tremble, they get dizzy.
She stops caring for people, stops believing that they love her. She has no control over his body or over his most devastating, negative and repetitive thoughts. The suicidal thoughts invade her.
More than 300 million people in the world are suffering from this mental illness as Ana.
Depression is the leading global cause of disability. It contributes significantly to the global burden of diseases.
In Latin America and the Caribbean, at least 5% of adults suffer from depression. That translates into more than 21 million people. Of these, 60% (around 12 million) do not go to the psychiatrist to be treated.
Ana is in this huge group.
What causes depression?
Depression is a common, serious and recurrent psychiatric illness. Its origin is heterogeneous. It seems to be the result of a combination of genetic, biochemical, psychological and social factors. Also, traumas or unhappy situations or high stress can trigger it.
The neuroendocrine, neuroimmune, neurotransmitter and neurometabolic systems become out of control and trigger depressive episodes. Alcoholism, drug addiction or social isolation can also trigger and worsen these episodes.
Besides, there seems to be a variable that links depression to diet. People with nutritious and varied diets have a lower risk of developing depression. It also seems that the key to this relationship is the intestinal microbiota. Enough evidence has accumulated to think the gut microbiota and brain activity.
Depression does not escape this observation. Animal studies suggest that intestinal microbiota impacts the neurobiological characteristics of depression.
When the microbiota is transplanted from a stressed animal to a healthy one, the healthy one alters its behaviour.
Some lactobacilli and bifidobacteria can modulate depression and stress-related behaviour in animal models. Actually, studies in healthy people begin to suggest that the consumption of prebiotics and probiotics can positively affect mood and anxiety. These foods are called psychobiotics.
Can the intestinal microbiota of depressed patients transmit the symptoms of the disease?
Irish researchers carried out a curious experiment for answering this.
The study consisted of performing stool transplants from depressive patients to healthy rats.
The results and conclusions were published in the Journal of Psychiatric Research in July 2016.
The researchers gave a cocktail of antibiotics to the rats every day for a month. They needed to ensure the elimination of any bacteria in their intestines. Then, they transplanted faeces from patients diagnosed with depression to the rats. There was, of course, a control group of rats who received faeces from healthy people. One week after the stool transplants, they performed behavioural analysis and blood tests to the rats.
The researchers showed that rats transplanted with faeces from patients with depression avoided open spaces, were less able to memorize mazes and showed less interest in consuming sugar. This behaviour is known as anhedonia, which is the inability to feel pleasure.
The levels of tryptophan in the blood were high and the intestinal transit was accelerated, features typical of depression.
Like Ana, the rats had saddened.
The researchers analyzed the diversity of bacteria in the poop of depressed rats. They found that the rats that received the stool transplants had reduced both the richness and the number of bacterial species.
As well as the patients, the depressive rats had their intestinal microbiota altered. It was less diverse.
What to do?
Regarding Ana, I would try to keep her as distracted as possible with light physical activities in the open air, but not before asking her to seek medical treatment.
When overcoming the depressive crisis, she should do everything possible to increase the consumption of fibre and fermented foods in her diet.
I would trust that this could result in the development of a microbiota allied in its physical and emotional well-being.
Neither Ana nor the rest of the 350 million people with depression should be ashamed of their condition, they should ask for help.
The only shame (as the WHO says in the video below) is that they are losing their lives.
References: John Kelly et al. (2016) Transferring the blues: depression-associated gut microbiota induces neurobehavioural changes in the rat. Journal of Psychiatric Research, 82: 109 – 118. Alper Evrensel y Mehmet Emin Ceylan (2015) The gut-brain axis: the missing link in depression. Clinical Psycopharmacology and Neuroscience, 13(3): 329 – 244.