The Tired Brain: A Risk Factor for Depression in Adolescents

Articles

It seems to be rather rare for adolescents to value sleep. There quite frankly, isn’t much time for it, if you think about it! The stress of managing schoolwork; if not managing, thinking about managing schoolwork, social lives and the sheer crisis that comes from simply being a teenager disallows one to truly prioritise sleep.

People affected with mental health issues can often trace it back to their teenage years. The reasons behind this are constantly debated and investigated, in order to help find some recourse. That said, a recent study published in the journal of Behavioral Brain Research associates depression in male and female adolescents to disrupted sleep patterns during teenage years.

It is reported that depression is the most prevalent mood disorder, affecting over 264 million people around the world. By way of information, the diagnosis of depression is twice as high in females than in males; many however speculating that this may be due to a persistent stigma against men’s mental health. Given the isolation brought about by our ongoing pandemic, depression cases are dramatically rising, making this a critical issue requiring our immediate, undivided attention.

Researchers from the University of Ottawa have recently published their newest findings on what seems to be an important risk factor leading to adolescent depression: sleep disturbance.

In a study involving mice, researchers exposed 80 male and female adolescent and adult mice to disrupted sleep, administered manually. The mice’s sleep was either undisrupted or disrupted during the first four hours of each rest cycle (8AM to 12PM) for 8 consecutive days. After being exposed to these conditions, the mice were exposed to a stressor – a swim test! They were put in 4L beakers with 3L of water for 5 minutes. During which, the mice’s behaviour was observed by experimenters for depressive-like behaviours.

The findings provided several interesting explanations for the sex-differences in depressive diagnoses and the timeframe in which individuals are most sensitive to depression.

The depressive-like behaviours during the swim test, were characterized by the manner in which they acted, during this particularly stressful task: did they attempt to climb out? Did they swim, or simply remain immobile?

The outcome had largely been predicted; eventually the little mice would possibly surrender and become immobile. The researchers measured the amount of time it took them to eventually come to this position. The mice that remained immobile or were quick to become immobile were said to have depressive-like behaviours.

To the surprise of none, adolescent male and female mice showed significantly more depressive-like behaviours compared to their adult counterparts. This suggests that the adolescent brain is more susceptible to depressive-like behaviours when presented with a stressor and sleep disruption, when compared to the adult brain.

After only 7 days of repeated sleep delays, the adolescent male and female mice started showing increased activity in the prelimbic cortex of the brain, the adult mice did not. The prelimbic cortex’s role has been associated with coping strategies. The prelimbic cortex allows rodents to respond and adapt; be it with a stressful stimulus or a changing environment. It is worthy to note that if it is overstimulated, there is risk of damage.

The Prelimbic cortex (blue area) in the rodent brain.

Another finding was that the adolescent mice showed sex-differences in their experience of sleep disruption. Adolescent females showed greater stress hormone release and activation of stress-sensitive brain cells than adolescent males following repeated sleep delay.

These findings infer that depression might originate during adolescence due to the overexposure to stressful stimuli. Additionally, the sex-differences in diagnosis of depression is partially explained by vulnerability of the females to chronic stress. Therefore, a tired brain is less robust in face of stressful situations–the abundance of which, during adolescence, has the proclivity to cause depression.

During this pandemic, adolescents are having to resort to remote learning, with some having to adapt to time differences, inevitably impacting sleep patterns negatively. Therefore, they could be at increased risk of suffering the consequences of sleep disruptions.

The authors of the study astutely observed that, “Proper management of adolescent male and female sleep schedules could reduce the risk of depression onset in adolescent humans.” Perhaps a finding we must become more aware of and alter our sleep patterns to lead healthier lives.

On a slightly different tangent, albeit an interesting one, you may have noticed that most studies, included the one discussed above, use mice testing to debunk or understand certain phenomena. Would you like to share your thoughts on mice testing? Are there any ethical considerations of mice testing that are particularly alarming, and up for debate? Should they be put under such distress for our benefit?

Let us know in the comments below!

Original Source:
Murack, M., Chandrasegaram, R., Smith, K., Ah-Yen, E., Rheaume, É., Malette-Guyon, É., Nanji, Z., Semchishen, S., Latus, O., Messier, C. and Ismail, N., 2020. Chronic sleep disruption induces depression-like behavior in adolescent male and female mice and sensitization of the hypothalamic-pituitary-adrenal axis in adolescent female mice. Behavioural Brain Research, p.113001.

Article Link: https://www.sciencedirect.com/science/article/pii/S0166432820307002?via%3Dihub

Featured Photo by Andrea Piacquadio from Pexels
Edited by Malavika Ramanand

3 thoughts on “The Tired Brain: A Risk Factor for Depression in Adolescents

  1. Really interesting article Ines! Mice testing is definitely a tricky one… In a way, we are lucky to have such ideal model organisms for our research, but we should also value their lives! I am hopeful that we will soon be able to create our own model organisms using stem cells.

Leave a Reply to Sophie Krug Cancel reply

Your email address will not be published. Required fields are marked *