Depression is thought to be caused by many factors, whether it is from trauma during development or later on in life, over exposure to negative stress, less positive reinforcement during adolescence, or brain chemistry due to drug use etc. Is it preventable or curable? Obviously not yet, but maybe the advancement of science can provide insight into the future treatment of depression. It is obvious that some people are more susceptible to depression than others. Some people just handle stressful situations better than most and are more resistant to depression. But why? Well, if you Google search "Causes of Depression" one of the first links will be from PubMed explaining the biology of depression. It states that studies have found that people with depression have significantly less serotonin receptors in their brains due to decreased hippocampus size. Interestingly, this shows that a lot of the causes of depression are probably due to genetics or the biology of our bodies rather than drugs or stressful lives.
Significant scientific and technological advances now allow us to study and try to understand the biology behind depression and why most people are more resistant to it. Recent studies found in PubMed Central show that differences in the function, balance, and interaction of different biological factors responding to stress cause the inter-individual variability in stress resistance. This article shows different reasons behind depression and suggests factors that might help promote resilience to stress and depression in different biological systems, such as the HPA axis, norandrenergic system, serotonergic and dopaminergic systems, and many more. The study also suggests that individuals can be trained to modulate their own brain activity by the use of forms of psychotherapy, as well as many other non-drug-related possible treatments for depression.
But how do all of these studies on depression and stress resilience apply to modern medicine? Well, in a study done on mice found in Science Magazine, useful information for the development of naturally acting antidepressants is given. It reveals more information on the complex inner workings of DA (dopamine) neurons, the main ingredient of many antidepressant drugs. (This video explains the dopaminergic system and how it is set up and spread out in the brain as well as some of its functions). The study focuses on the neurophysiological mechanisms of the brain’s response to chronic social stress in susceptible (depressed) mice compared to (normal) resilient mice. The study expected to find that the hyperpolarization-activated cation channel–mediated current (Ih) of these neurons would normalize after a stress response in the resilient mice. However, they actually found that it showed an increase of this current as well as increased K+ channel currents in the ventral tegmental area (VTA) dopamine (DA) neurons of the brain in the resilient mice. This new information helps better understand the complexities of the dopaminergic system, to then help develop more efficient forms of antidepressants in the future that can be more natural and potentially less dangerous than pharmaceutical treatments for depression. Currently, doctors most often prescribe selective serotonin reuptake inhibitors, or SSRIs to keep more serotonin in the brain of depression patients, and hopefully lightening their moods. However, these drugs do have adverse enough side effects to have the FDA issue multiple warnings about many of these kinds of drugs.
Obviously science is showing promise of new treatment alternatives to depression in many different ways. I believe that this news alone shows hope for people suffering with depression and hopefully science can do more for these people in the near future based on ongoing studies, and make treatment safer as well.
Posted by Ashley Condon (Group A)