The Encumbrance of Depression

Depression is the single largest disability which has afflicted nearly two-thirds of the humanity. More than 350 million have been affected depression so far making it a most common disorder. Nearly two –thirds of people suffering from depression attempt suicide. But it has been least researched though the instances of depression are increasing at a quicker pace, the remission methods are still not clearly chalked out. Almost three quarters of people suffering from depression go undiagnosed, had it been the case with cancer care, it would have been reckoned as calamitous. But unfortunately, the patients suffering from depression are often ignored and are not extended proper care. There is still a social stigma attached to the disorder.

The three most common mental disorders are anxiety, depression and substance use. Surprisingly, honest and meaning full conversations on these mental disorders are shunned. The tragic death of comedian and actor Robin Williams brought the discussions on the mental disorders into forefront. Issues related to mental health or more specifically mental disorders have been associated with social stigma. Of late the stigma of living with depression and other mental disorders has reduced considerably as people suffering from depression have started openly sharing their experiences in their life. Depression is a scourge on mankind. Of the top ten causes of disabilities depression accounts for maximum healthy years lost as they live with both physical and mental disability. Nearly 76.4 million years are lost to disability (YLD) due to depression world-wide. But unfortunately depression is undiagnosed and untreated due to social stigma. It is startling that nearly half of the world population has 2 psychiatrists per 100,000 people.

Paltry funding for research on mental health:

Depression research as such receives paltry funding and is unable to garner much attention and scientific resources over a period of time. While new diagnostic techniques, disease-associated mutations, genetically targeted therapies and sophisticated animal models have been developed for other disorders depression research has floundered. It is important to understand often research agendas are dictated by political, social and economic concerns. Thus, while there has been a great deal of public uproar to fight cancer, there is no strong political or public will to wage a war against depression. Mental health research receives just one-fifth of funding as compared to cancer research. Many people still believe that depression is a legitimate condition and is associated with lot of social stigma.

 

Cancer Vs Depression:

Some scientists opined that cancer too once carried a stigma around 70’s. But the awareness created by advocacy groups changed people’s perception towards cancer who were sensitised that cancerous tumours can be monitored and removed. Depression, on the other hand affects deeply entrenched tissues of brain which can neither be seen nor removed. Moreover people failed to acknowledge that mental illness is a real illness. Depression is associated with anxiety and difficulty in communication and other psychiatric disorders. Though depression is perceived as human blight, its well-defined traits are not identified so far. Hence the ground for diagnosis is still clumsy. Further, the researchers working on depression are laid back by the existing belief that it is intractable. Unlike cancer studies which progressed remarkably due to the animal models depression studies are hampered by the inability to develop a suitable animal model which can truly mimic human conditions. Depression studies involve unravelling of intricate human circuitry which is extremely complex. They require studying single cells, mapping neural connections and activating specific brain centres. By and large research on depression so far was hampered by the unavailability of tools and the basic information.

Equipped with the required ensemble to unlock the mysteries of neural circuitry, researchers are now confident of waging a war against depression. As thought earlier, treating depression is not about replenishing brain with tonnes of neurotransmitters, it is about fixing woefully functioning neural networks. With the availability of new techniques in imaging to guide surgery and deep brain stimulation scientists are hopeful of relieving the disorder of depression.

 

Existing Treatments:

Anti-Depressants Medication Vs Cognitive Behaviour Therapy:

The first line of treatment for depression has been anti-depressants which relives nearly 20-44% of patients from depression. Another important treatment is Cognitive Behaviour Therapy (CBT), which helps to identify and change the negative and self destructive thought patterns. CBT has been useful in treating some subjects. Depression is a complex disorder and manifests in people in different ways. Depression stems from deep seated negative thought patterns.  CBT, a kind of psychotherapy is aimed at inculcating a positive thought process wherein depression symptoms are relieved in some patients. The consequence has been improved mental health.

Neuroimaging techniques indicated there are detectable differences in the two primary systems of brain: prefrontal complex and amygdala. Prefrontal complex is responsible for complex mental tasks like planning and self-control while the limbic system including amygdala is involved in emotional processing. In healthy people prefrontal complex inhibits the activity of amygdala keeping the emotions under check. The prefrontal cortex is relatively weak in people with depression. fMRI, functional magnetic resonance imaging also suggests that amygdala has increased levels of activity in depressed people. CBT is speculated to increase the activity of the underutilised prefrontal complex and helps in quietening the hyperactive limbic system. While CBT worked effectively for some individuals, antidepressant medication offered great relief for others. To sum up, the complex networking of brain goes haywire during depression and these broken systems of different individuals respond differently to different treatments. In general it was found that relapse of depression symptoms are minimal after CBT than people who stopped antidepressant medication. Married people are more benefitted from CBT than medication.

 

Way Forward

Discovery of new drugs & Genetic Studies:

Though scientists have employed molecular and neurological clues to develop new drugs, but most antidepressants or psychotropic drugs are arrived at through serendipity. The calming effects of benzodiazepines and lithium have been accidentally discovered in animal experiments. These kinds of drugs were effective on few people other failed to respond. Depression lacks a distinctive pathology and hence designing new drugs is highly challenging. Another promising clue with effective solution for depression is through genetic studies. Risk of depression is highly polygenic involving hundreds of genes. Since the disease mechanism is not known, more than 100,000 with Major Depressive Disorder (MDD) are needed to trace the genetic loci that help in designing therapeutics and in understanding the biological phenomenon. Latest technological developments galvanised genetic analysis which yielded powerful clues in autism, schizophrenia and bipolar disorder.

Probiotics: Effective link between Gut and Brain

Companies selling probiotic foods had for a long time widely popularised the benefits of cultivating healthy gut bacteria but neuroscientists had reservations about the same. Gut bacteria together in scientific parlance are referred to as microbiome. Probiotics are ingested microorganisms associated with beneficial effects to humans. These are basically good bacteria. The concept has been introduced way back in 1907 by the Nobel Laureate Eli Metchinkoff who suggested that “the dependence of the intestinal microbes on the food makes it possible to adopt measures to modify the flora in our bodies and to replace the harmful microbes with useful microbes”. It is known that digestive tract is home for trillions of bacteria and they account for 3% of the body weight. Studies show that these bacteria affect the dense network of neurons in the gut, now deemed as the second brain. A microbial imbalance in the gut or dysbiosis has been associated with chronic fatigue, obesity, physical ailments and certain types of cancer. Though the exact mechanism through which these bacteria can cause or cure the ailments is known but growing evidence has sparked greater interest among the scientists towards probiotic research.

Scientists of California Institute of Technology, Pasadena believes that bacterial waste products have an influence on the brain. Particularly the Vagus nerve that connects digestive tract to the brain might have an important role to play. Two types of intestinal bacteria are found to produce ϒ- amino butyric acid (GABA), a neurotransmitter. The new observations assume greater significance due to the dogma of nothing can cross the brain-blood barrier prevalent in the scientific community. This essentially means that brain is sealed off from rest of the body and protected from infection. But new evidence effectively shows that there is an apparent communication between the brain and the gut.

In an experiment carried out at University of Cork, Ireland found that mice born by caesarean section had a different microbial composition compared to the vaginally delivered mice. The former were more anxious and had symptoms of anxiety. Inability to pick up mother’s vaginal bacteria may have led to lifelong changes in mental health.

Mice with autism were found to have low levels of common gut bacterium Bacteriodes fragilis than the normal mice. These animals were stressed, antisocial and had gastrointestinal symptoms characteristic of autism. Symptoms were reversed when then mice were fed with B.fragilis. The stressed mice were also found to contain higher levels of bacterial metabolite 4-ethyl phenyl sulphate (EPS) in their blood. When normal mice were injected with EPS it exhibited similar behavioural symptoms as autistic mice. Though the mechanism of action is unclear, the changes in the behaviour may be outcome of a leaky gut since the chemical seeped into body through intestinal wall. These observations raise the possibility of Probiotics as a promising therapy for autism as they target gut instead of brain which is a more complex and inaccessible organ.

Currently there is a great excitement about the role played by the microbiome on the body hence large scale DNA profiling had been initiated to identify various bacterial species of the gut. Probiotics are becoming increasingly popular international organisations like FAO (Food and Agriculture Organisation) and WHO (World Health Organisation) has also validated certain of the recommendations of the probiotic research. Both the organisations have endorsed the use of probiotics as an effective ‘alternative’ besides the recommended medications for regression of psychological disorders and other body ailments.

 

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Historic Feat of Comet Touch Down

Rosetta spacecraft with its numerous distinctions has enthralled the scientific community with its spectacular accomplishments till now. It is on the verge of making a momentous history in Space explorations if it succeeds in sending out the lander Philae probe onto to the surface of the Comet 67P/ Churyumov-Gerasimenko on November 12^th. In its illustrious decade long solar mission, Rosetta, the brainchild of the European Space Agency (ESA) triumphantly accomplished all its tasks with meticulous accuracy. It is now poised to enter the last and crucial phase of its mission of sending the landing craft Philae to the icy comet surface.

In what is termed as the most scientifically challenging mission in the history of the space explorations so far, scientists will be aiming to accomplish a near impossible feat. In common parlance, mission experts are trying to transfer an object from one speeding bullet train to another. At nearly 500million Kilometres distance from earth, between Mars and Jupiter, a robotic probe of 100kg Philae lander will be ejected from the space craft Rosetta and land on the Comet surface which it has been chasing from 6th August 2014. Both of them are flying at a speed of 65,000 km an hour. The task is onerous as crucial details like the densities, surface atmosphere of the Comet and other details of the landing site are not known. Moreover, the unusual double lobed shape of the Comet is not known until the recent images have been sent little earlier. Ever since its launch in 2004, Rosetta used the gravity of Earth and Mars as a slingshot to enter the Comet’s trajectory. In August, Rosetta became the first spacecraft to orbit around a comet.

Comets are the small icy bodies which originate either in the Oort Cloud that exist far beyond the orbit of the Pluto or from the Kuiper Belt located beyond the orbit of Neptune and releases gas or dust. As comets dart towards sun they get heated up and begin to outgas thus displaying visible atmosphere or Coma and sometimes a tail posing technical challenges for landing. Usually the dust consists of ice, carbon dioxide, ammonia, methane and more.  

Rosetta pictures indicated that surface of the comet was highly undulated with wicked slopes and elevated rocks. Philae piggybacking on Rosetta will separate from its mother, from a distance of 12 kilometers from comet on 8:35 GMT with unfolded legs. The self-adjusting landing gear will ensure Philae stays upright. It will escape the weak gravity of comet by shooting out its harpoons into the surface. If everything goes as expected, the confirmation signals would reach earth by 16:02 GMT.

The Philae lander will touch down on a selected site on the Comet, Agilika named after an island in Nile. It will land on the smaller of the comet’s two lobes. Since the mechanical details of the comet are not known, the lander which is of size of washing machine is armed with all the structures that can facilitate a smooth landing. Its legs would cushion the impact of landing while ice screws on its feet would provide extra grip on the icy terrain. A thruster will fire to cancel out the bounce and its two harpoons will anchor the robotic probe to comet’s surface. Any technical glitch or misalignment of the spacecraft even by 1cm can cause the probe to drift hundreds of miles away from the target and can jeopardise entire mission. Mission officials predict a 70% success rate. The lander has 11 instruments on board to analyse the environment, surface and chemical properties of the comet. The instruments can dig the surface and heat them to measure their properties. Scientists expect to find water and other organic compounds that might provide an insight into understanding the earth and how life on earth emerged.

Rosetta is expected to drift alongside the comet till Dec 2015. Equipped with batteries that has 60 hrs operating time, it can last till March if sunlight and temperature are optimum for solar panels. Philae can drill and analyse the subsurface details of the comet with the instruments its houses and relay the data to Rosetta which is subsequently passed onto the ground station Darmstadt, Germany. The gentle free fall is expected to last for seven hours.

Evolutionary biologists believed that numerous comets impounded the surface of fledging earth 4.6 billion years ago bringing with them water and other organic compounds needed for generation of life on earth. A critical analysis of the comet mass would help understand in detail the evolution of the solar system. Scientists are hoping to find L-amino acids the backbone of the proteins of the living organisms. The nerve wrecking space adventure akin to a sci-fi fiction is tipped to mesmerize the scientific community and science enthusiasts with its unseemly arduous task.

 

 

 

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