By definition, depression is generally categorised as a mood disorder that changes the way you think, feel and behave. The disorder is usually marked by a feeling of gloominess and hopelessness that can extend for an indefinite period of time. It might last for a few days or could go on for years. It is important to note that these feelings are far different than being disappointed or feeling low about a minor issue that hasn’t gone in your favour.
Depression does not have a set pattern. Some may only experience a mild version of the disorder only for a single instance in their lifetime. While others may afflict with several bouts of the disorder through their life, which has the potential to be quite severe. This long-term and serious form of the disorder is classified as a major depressive disorder (MDD) or clinical depression or, simply, major depression.
The onset of the disorder is marked by the symptoms that hinder daily routines, normal activity such as education, work and social interaction. The symptoms also have an effect on mood and behaviour along with other bodily functions like sleep and appetite. For a positive MDD diagnosis, an individual is ought to display a particular set of symptoms at least once a day over a 15 day period:
1. A continuous feeling of sadness and hopelessness
2. Disinterested in doing most activities, including the ones that they liked doing or enjoyed
3. An increase or decrease in appetite along with an intense weight loss or weight gain (respectively)
4. A marked change in sleeping patterns—either too much or too little
5. Feeling tired all the time
6. Overwhelming feelings of guilt or worthlessness
7. Suicidal thoughts or thinking about death constantly
8. Attempting suicide
It is possible for people of any age group to develop MDD but the average age estimate is 32 years—though it can affect children and teenagers just the same. For adults and children alike, treatment involves a combination of psychological counselling, medication for treating depression or a combination of these two.
Effects on the Brain
The hippocampus, amygdala and prefrontal cortex get affected when a person suffers from depression. Hippocampus—located in the central part of the brain—is responsible for storing memories and aids in the optimal production of cortisol. It is a hormone that is released when the body experiences stress physically or mentally. Trouble arises when an excess of cortisol is produced in response to stress. Or, in case of a chemical imbalance in the body. Brain cells or neurons are produced throughout adulthood in the dentate gyrus which is a part of the hippocampus. For those suffering from MDD, extended exposure to cortisol can interfere with the formation of these neurons. Which can even lead to existing neurons in the hippocampus to shrink in size, which can cause trouble with memory.
Another area of interest is the prefrontal cortex. Located at the front of the brain its core functions include regulating emotional response, decision making and forming memories. In a situation where there is excess cortisol production, this area also shrinks in size.
Fear and pleasure responses are managed by the amygdala and for those suffering from MDD, this part of the brain increases in size. This is due to constant exposure to high amounts of the hormone cortisol. This, coupled with abnormal brain activity in other areas, can lead to alterations in the sleep cycle and activity patterns, and the secretion of other hormones and chemicals in the body, causing further imbalance.
Most researchers hold that it is the cortisol levels that have a far-reaching impact on altering the physical form and chemical levels that can ultimately lead to MDD setting in. Unlike healthy individuals, cortisol levels of those suffering from MDD are high even during the night time.
How does treatment help
The most effective treatment is restoring a balance in the level of cortisol and other chemicals to restore hippocampus size. The same holds true for chemical levels in the body, which help in managing and bringing down the symptoms of MDD. This is usually done through the use of medication to help combat the effects on the brain and the subsequent chemical balance.
Psychotherapy has also proven effective in changing the brain structure, especially the prefrontal cortex and manage the symptoms associated with MDD.
Brain health can also take a boost without medication. Eating nutritious foods and undertaking some level of physical activity to stimulate the brain are beneficial. Avoiding alcohol and other drugs that have potential to destroy brain cells is a must. Moreover, discussing your symptoms with the doctor can help with a treatment plan better.