In this article we discuss the major causes of depression and some of the most successful treatment options available.
Either directly or indirectly, depression is a condition that touches us all. It is experienced by approximately 10 to 15 percent of adults every year and rates are predicted to increase over the next decade.
Depression is commonly treated with antidepressant medications and psychological therapy, which are both reasonably effective. Unfortunately, they are far from perfect with research indicating that approximately 30 percent of people receive no benefit from these treatments.
From a biological standpoint, the most commonly-held belief is that depression is associated with a deficiency in certain brain chemicals (or neurotransmitters). These neurotransmitters help transmit information across the brain and can influence mood and behaviour.
Serotonin is one neurotransmitter that is particularly implicated in depression. Low levels, or a reduced sensitivity to serotonin, are believed to impact on mood, leading to feelings of sadness, a lack of drive, sleep problems, appetite changes, irritability, plus many more.
To combat this problem, serotonin deficiency is treated with antidepressant medications known as selective serotonin reuptake inhibitors (SSRIs), such as Prozac®, Lexapro®, and Zoloft®.
Over the past decade researchers have confirmed that biological factors associated with depression are more complex than the simple neurotransmitter deficiency theory. Depression is actually caused by several physiological disturbances associated with inflammation, a hypersensitive stress response, free radical damage, and neurodegeneration.
In terms of inflammation, it is now confirmed that on the whole, people with depression have greater inflammation. Certain proteins in the blood called cytokines and C-reactive protein are increased during times of inflammation. People with depression have consistently higher levels of these markers compared to non-depressed individuals. While acute (short-term) inflammation is necessary for healing and recovery, chronic (long-term) inflammation can affect the brain. In fact, inflammation can actually lower levels of serotonin. So it is possible that the lower levels of serotonin in people with depression may actually be caused by inflammation.
Free radicals are unstable molecules circulating in our body. When levels of free radicals are consistently elevated, they can damage cells, tissues, and organs. Antioxidants combat free radicals so that they do not run rampant in our body. Unfortunately, people with depression have higher free radicals, and lower antioxidant levels. This creates a condition known as ‘oxidative stress’, which can affect brain function and possibly mood.
Our fight or flight response is part of our stress response. When danger is real, this stress response is important as it helps our body to get ready to fight or flight. Hormones such as adrenaline and cortisol are increased during times of stress, and have the effect of mobilising our internal organs to do the necessary tasks they need to do to protect ourselves. The problem is that when this stress response is turned on for too long it can damage our organs, including our brain. On the whole, people with depression have an increased (hypersensitive) stress response.
All these mentioned biological factors can significantly affect our brain function. Low levels of neurotransmitters, increased inflammation, oxidative stress, and a hypersensitive stress response can lead to degeneration in certain parts of the brain. In fact, the longer someone suffers from depression, or the more episodes they experience, the greater the brain damage. To make matters worse, people with depression have lower levels of brain-protective proteins, called neurotrophins.
While depression is a common condition suffered by many people, there are effective treatments available. Given the complexity of depression, a simple ‘one-size-fits-all’ solution is unlikely to be the most effective. Treatment should be multi-targeted comprising psychological, lifestyle, nutritional, and biological treatments.