The science behind SAD.

Because I am British, it probably comes as no surprise that I unequivocally understand the heartbreak of traditional rainy weather. An indestructible stereotype of the UK, bad weather has never really manifested the ability to catalyse happiness during the morning commute. Whilst the occasionally odd shower is often welcomed, consistent wind and rain provokes noticeable negativity in people – have you ever been in central London during commuting hours? Yikes. Why then, for many of us, does our mood shift in association with the weather? Interestingly, science may have the answer! This discussion is dedicated to what has been coined seasonal affective disorder. Here I will survey some of the evidence surrounding the condition and describe what we may be able to do to fight back against it!

Seasonal affective disorder: what exactly is it?

Seasonal affective disorder is a form of depression otherwise referred to as SAD or seasonal depression. As you may have guessed, people who suffer with SAD tend to experience mood changes and symptoms similar to depression. These symptoms appear to correlate with the changing seasons, primarily beginning in the autumn and winter months, before alleviating during the arrival of spring. With this in mind, it is important to note that SAD is more than just “winter blues”. The symptoms can be distressing, debilitating, and can significantly interfere with daily functioning. Nevertheless, various treatment options are available.

Causes

Unfortunately, the biological cause(s) of SAD is still relatively unknown. However, some evidence suggests that it is related to the body’s level of melatonin, a hormone secreted by the pineal gland. Melatonin regulates the sleep-wake cycle, and darkness is known to stimulate its production, preparing the body for sleep. Because more melatonin is therefore produced during the winter months (when sunlight hours are diminished), people tend to feel sleepier and more lethargic. 

In addition, research suggests that some people who develop SAD may produce less Vitamin D. Interestingly, Vitamin D has been suggested to play a role in serotonin activity, a key mood regulating neurotransmitter which is reduced in some depressed patients. 

Treatments

Interestingly, human clinical trials have identified that both cognitive behavioural (e.g. talk) and light therapy improve the symptoms of SAD, wherein the latter may be more effective for reducing four key signs of the disorder: early insomnia, anxiety, hypersomnia, and social withdrawal. So, if you needed a sensible reason for an expensive winter holiday to the Bahamas… you are most certainly welcome. However, more practical approaches to tackling SAD symptoms include taking care of your general health and wellness, which involves (yep, you guessed it…) regular exercise, good nutrition and getting enough sleep. Spending time outside and rearranging your office space so that you are exposed to a window during the day may also be of benefit.

Does blindness contribute?

From a scientific perspective, there are many interesting questions arising from SAD research. For example, is it more common in people with serious visual impairment? Does the likelihood of developing SAD increase as eyesight progressively degenerates? What about people who are blind and have been since birth; do they develop symptoms of SAD? These are all interesting research avenues which are currently being investigated.

It is important to seek help

Whilst it is thought-provoking topic to discuss, please remember that If you feel like you or a loved one has experienced depressive symptoms for an extended period of time, contact your nearest doctor for support.

Untreated depression: It will damage your brain.

Image: Kat Jayne

It is a scary prospect, but it is something that has accumulated serious momentum. From a scientific point of view, I have to admit I do find it fascinating. However, from a health perspective, this is rather worrying. The conclusions being drawn? Untreated depression may be causing brain degeneration.

Considering one in four people in the UK will experience a mental health problem each year, this might raise concern. It becomes even more alarming with the publication of a recent study highlighting that approximately 35% of people newly diagnosed with depression refused to seek treatment. Without professional help, how long can depression toxify and contaminate an individual’s identity? Easily an entire lifetime. Not seeking help for prolonged periods of sadness or emotional absence may not be just affecting your character, as was often thought for decades. 

The ‘all in the mind’ mentality is dead. The divide between physiology and psychology was clearly defined for many years. When patients were physically unwell – because of say, a broken bone or arthritis – any accompanying mental health instabilities were waived off. Depression often accompanied these ailments (and still does, of course), but the diagnostic significance of such was irrelevant. If a patient suffering from a chronic disorder like arthritis said they were depressed, the general consensus amongst medical practitioners was: ‘well you would be, wouldn’t you?’. The same conclusion was always drawn. The patient was simply depressed as a consequence of the pain associated with their arthritis, or their broken leg, and so forth. No real attention looked into the other potentiality; what if the depression causes physiological ailments? What if a psychological disturbance could be having serious negative effects on the body?

In the 21stcentury, the argument for this is strong. Chronic, untreated depression appears to have a degenerative effect on the brain, damaging it from the inside. Here I want to highlight some key pieces of research which link depression to neurodegeneration. The idea here is to help us all understand just how important seeking assistance might be if you think yourself or a loved one might be suffering from a chronic depressive episode. Trying out different methods to combat depression will be beneficial both for emotional stability and life fulfillment, but also for the health of our brains, too.

A major finding was published when discovering differences in the brain scans of depressed and non-depressed patients. Looking at cases of major (clinical diagnosis of chronic) depression which had lasted for more than a decade, the Centre for Addiction and Mental Health in Ontario, Canada identified that during episodes of major depression, the patients’ brains would show signs of inflammation. The study group identified that a key protein associated with the central nervous system (brain and spinal cord) inflammatory response was approximately 30% higher in the brains of people who lived with depression for more than a decade. However, this isn’t the only study to report such a finding. Another study published in 2016 looked at the whole-body levels of CRP (another biological marker of inflammation) in patients with depression and those without. The observational studyidentified that depressed individuals exhibited CRP levels more than 30% higher than those without depression.

The results presented here are startling, collectively indicating that we may need to change our thinking about depression and its effects. The evidence strongly affirms that depression truly is a biologically based disorder, rather than something that only exists in the field of psychology. But how does this link to degeneration of the brain?

Whilst inflammation is used to protect the body from infection amongst other functions, excessive inflammation can cause extensive cellular damage. Chronic inflammation within the brain has been linked to several destructive neurodegenerative diseases. One of which is Parkinson’s disease, which primarily manifests itself as a movement disorder, wherein patients begin to show signs of slowed movement (bradykinesia), until movement becomes practically impossible without medication. This primary symptom is caused by the destruction of neurons in the portion of the brain which is essential for movement. Unfortunately, there is currently no cure.

Whilst the contribution of inflammation to Parkinson’s disease does not appear to be the primary causation, in Alzheimer’s disease it may be a different story entirely. Alzheimer’s disease is the most common neurodegenerative disease in the world. In the United States alone, approximately 5.7 million peopleare currently suffering with the disease, which is primarily associated with progressive and severe memory loss. Again, there is currently no cure. Recent researchpublished in the Lancetnow appears to highlight neuroinflammation as a central cause of Alzheimer’s disease, with many otherstudies further supporting this idea.

Multiple lines of research therefore support the idea that ignoring a potential major depressive episode could have considerably devastating consequences for the long-term health of the brain. What can we do to fight back? Alongside seeking professional support, as little as 20 minutes of exercisecan reduce your bodily levels of inflammation. This is alongside the general health benefits of exercise, including reducing the risk of type 2 diabetes and cancer. Diet is the next big consideration. There are several foods which should be avoided due to their contribution towards inflammation, including red meat and refined carbohydrates. On the other hand, there are many foods which are considered to be anti-inflammatory, including green leafy vegetables such as spinach and kale, fatty fish like salmon, and a range of berries. A more exhaustive list of pro- and anti-inflammatory foods can be found here. Supporting this switch in diet, women whose diets include more foods which trigger inflammation and fewer foods which restrain inflammation have up to a 41% increased risk of being diagnosed with depressionthan those who mostly eat a less inflammatory diet.

Depression is a biological disorder and we all need to take this into consideration. Its link to inflammation and bodily damage cannot be underestimated, and it is something we must consider when either ourselves or a loved one is currently suffering a major depressive episode. If you are adamant about not seeing a professional (I highly advise you do, however), exercising more and switching up our diets may provide an answer that we desperately need.