Depression :- A new analysis found serotonin level is not responsible for it .

 What is depression?

Depression is a widespread and dangerous medical condition that has an adverse impact on how you feel, think, and behave. Thankfully, it is also curable. Sadness and/or a loss of interest in previous hobbies are symptoms of depression. It can impair your ability to perform at work and at home and cause a number of mental and physical issues.

Depression:- According to WHO 

Depression is a common illness worldwide, with an estimated 3.8% of the population affected, including 5.0% among adults and 5.7% among adults older than 60 years (1). Approximately 280 million people in the world have depression (1). Depression is different from usual mood fluctuations and short-lived emotional responses to challenges in everyday life. Especially when recurrent and with moderate or severe intensity, depression may become a serious health condition. It can cause the affected person to suffer greatly and function poorly at work, at school and in the family. At its worst, depression can lead to suicide. Over 700 000 people die due to suicide every year. Suicide is the fourth leading cause of death in 15-29-year-olds. 

Although there are known, effective treatments for mental disorders, more than 75% of people in low- and middle-income countries receive no treatment (2). Barriers to effective care include a lack of resources, lack of trained health-care providers and social stigma associated with mental disorders. In countries of all income levels, people who experience depression are often not correctly diagnosed, and others who do not have the disorder are too often misdiagnosed and prescribed antidepressants.

Cause of depression

Lots of factors are responsible for the cause of depression. Some of the major causes includes . 

Inferiority feelings caused by certain instants that occurs in the person's life 

Certain type of physical, mental or sexual abuse may leads to depression.

Long term loneliness and comparing oneself with others .

Older people who usually are alone and are with less family and social support.

Sometimes the demise of the closed one leads to depression 

And a research shows that women suffer from depression twice more than the male does.

Let's keep these causes aside and let's talk about what changes occurs in our body that causes depression . Imbalance in the level of the Serotonin a neurotransmitter secreted in the brain is believed to be the root cause of depression.

When compared to those who do not experience clinical depression, researchers have found changes in the brains of those individuals. For instance, some people with a history of depression tend to have smaller hippocampuses than others who have never had depression, a tiny region of the brain that is essential for memory storage. There are fewer serotonin receptors in a smaller hippocampus. One of the many neurotransmitters—brain chemicals that enable communication between circuits connecting the brain areas involved in processing emotions—is serotonin.

The hippocampus may be smaller in certain depressed individuals for unknown reasons. Researchers have discovered that sad persons create an excessive amount of the stress hormone cortisol. According to these researchers, cortisol has a harmful or "shrinking" effect on the hippocampus' development. According to some scientists, sad people may just have a smaller hippocampus at birth and are hence predisposed to depression. It is likely that no single brain structure or pathway can fully explain clinical depression because there are numerous additional brain regions and connections between particular regions that are known to be related with depression.

One thing is certain: Depression is a complex illness with many contributing factors. The latest scans and studies of brain structure and function suggest that antidepressants can exert "neurotrophic effects," meaning that they can help sustain nerve cells, prevent them from dying, and allow them to form stronger connections that withstand biological stresses. As scientists gain a better understanding of the causes of depression, health professionals will be able to make better "tailored" diagnoses and, in turn, prescribe more effective treatment plans.

But now a new theory has come forward

This new study suggests that depression may not be caused by the lower levels of the Serotonin in the brain.According to a recent review of 17 prior studies, there is no proof that depression is brought on by decreased serotonin levels or activity. According to the review's authors, this shows that a chemical imbalance of this brain-signaling molecule is not the root cause of depression. They note that it also calls into doubt the efficacy of antidepressants that purport to target serotonin. It would be oversimplifying the data, according to other academics, to entirely rule out serotonin because the chemical and neurological causes of depression are complicated. Antidepressants have been demonstrated to be modestly beneficial for some people, thus they advise against basing treatment choices for depression on this review.

The director of the Frances and Kenneth Eisenberg and Family Depression Center at the University of Michigan and professor of depression and neurosciences Dr. Srijan Sen said he didn't believe the current review completely eliminated serotonin from the equation. It's unclear, he said, "if serotonin plays a role in depression in some manner." Given how intricate and complex the brain is, it would be remarkable if serotonin wasn't at all involved. He emphasized that there is still more to be learned about serotonin by citing a recent meta-analysis of studies that examined the relationship between stress, depression, and serotonin-related gene variations.

In that study, scientists discovered that persons who had a certain serotonin-related gene variation are more likely to experience depression after experiencing a traumatic incident. This, however, only applied to depression and chronic stress that had been diagnosed within a year of the stressor. This meta-analysis was just released this month, thus Moncrieff and her associates did not include it in their review. Sen does concur with Moncrieff and her associates on one point, though: "[Chemical imbalance] is not an accurate depiction of our understanding of what happens in the brain," he said.

He asserted that it is more plausible that specific circuits and loops of connections in the brain undergo substantial changes. "But we're not entirely sure what's going on," King asserted that there are additional perspectives on depression that can aid individuals in escaping the downward cycle that frequently accompanies this illness. He remarked, "[Stressful life circumstances] might result in emotional upheaval and a significant transformation. "That might come with a specific kind of pessimism and a particular way of acting and thinking." In essence, he observed, "people get into ruts - they get into ruts intellectually and behaviorally." And a feeling of inertia develops. Although it may seem difficult to break this cycle, King said numerous treatment modalities, such as cognitive behavioral therapy, behavioral activation, and mindfulness, can aid in getting people moving once more.

The current review questioned the usefulness of referring to SSRIs as correcting a chemical imbalance. According to Moncrieff, "many patients take antidepressants because they have been told that their depression has a physiological explanation. However, this new research reveals that this belief is not supported by data." Sen, however, urged people not to base treatment choices for depression on this analysis. The molecular and scientific understanding of the actions of the therapies is typically not taken into account while making therapeutic judgments, according to Sen. It is based far more on the findings of clinical research.

Rigid clinical trials are used by scientists to determine whether a treatment is effective as well as under what circumstances and for which individuals. Sen. Feinstein stated that even without a thorough grasp of how a medicine operates, these trials can still yield helpful data. In light of this, he continued, "I think that knowing biology in the long run will help us produce better pharmaceuticals and breakthroughs in individualized therapies." Clinical studies of SSRIs to date have revealed that "they are moderately effective and benefit some people," according to Sen. But better medications are unquestionably required.He noted there are other possible treatments for depression, such as better sleep habits, consistent exercise, and stronger social relationships, for people who don't benefit from SSRIs. In recent years, taking psychedelic substances like ketamine has grown more popular as a treatment option for depression. There is observational and clinical trial evidence that all of these activities are effective for treating depression, he said.