Depression and the Brain - The Upward Spiral

THRIVE NOTES - Summarising Books on Wellbeing

Welcome to THRIVE NOTES, a series of articles where we’ll be summarising the key points of a range of chapters from self-help, wellbeing, and science-backed books. While we recommend that you pick up the book yourself (and each book that we cover will also be added to our Wellbeing Pit Stop in Senate House), we hope that these articles will offer you some guidance through the book’s key information and encourage you to pick it up for yourself!

What’s the Book About:

The Upward Spiral, written by neuroscientist Alex Korb, explains how downward and upward spirals work, through hormones and neural systems in the brain. Korb then guides us on starting those upward spirals that can move us closer to getting out of periods of depression, unlike downward spirals, which tend to keep us feeling hopeless, helpless, and stuck.

Summary of the Chapter: A Brain Map of Depression

What is Depression?

A brain scan, like an MRI, cannot show us whether a person has depression or not. Rather, depression is diagnosed as a collection of symptoms, which are a result of our brain’s circuits. These symptoms include:

• Depressed mood, such as feeling sad or empty or even constantly irritable
• Decreased interest or pleasure in all—or almost all—activities
• Significant (and unintentional) weight loss, weight gain, or decrease or increase in appetite
• Insomnia or increased desire to sleep
• Either restlessness or slowed behaviour that can be observed by others
• Fatigue or loss of energy
• Feelings of worthlessness, or excessive or inappropriate guilt
• Trouble thinking, concentrating, or making decisions
• Recurrent thoughts of death or suicide

Displaying five or more of these symptoms over the course of two weeks may mean that a person has Major Depressive Disorder (although, this should be formally diagnosed by a mental health professional).

Having depression doesn’t meant that there’s anything wrong with your brain. It’s just the way your brain is wired. Korb uses the example of tornadoes in Oklahoma, just tornadoes are more common in Oklahoma, rather than New York, doesn’t mean that there’s anything wrong with Oklahoma. It’s the same with your brain. It may be tuned to be susceptible to depression, but it’s by no means bad or wrong.

Depression and the Brain

The brain is made of neurons (nerve cells), these power the brain by sending along electrical pulses. In order for these electoral pulses to travel from a neuron to other cells, the neuron produces a neurotransmitter (a chemical message) to connect the cells, across the synapses (the space between the cells).

The more electrical pulses sent along a path, the more a pattern is developed.

The brain’s cortex (the surface, including the brain’s wrinkles) is split into regions, with different collections of neurons (as neural circuits) for different functions. Korb say that it’s like having lots of small computers in your brain.

Different neurotransmitter systems have their own purposes and can impact these neurotransmitters/hormones:

• Serotonin—improves willpower, motivation, and mood

• Norepinephrine—enhances thinking, focus, and dealing with stress

• Dopamine—increases enjoyment and is necessary for changing bad habits

• Oxytocin—promotes feelings of trust, love, and connection, and reduces anxiety

• GABA—increases feelings of relaxation and reduces anxiety

• Melatonin—enhances the quality of sleep

• Endorphins—provide pain relief and feelings of elation

• Endocannabinoids—improve your appetite and increase feelings of peacefulness and well-being

Depression can be due to poor communication between the prefrontal cortex and the limbic system. Together, these are known as the fronto-limbic system, which regulates your emotional wellbeing.

The prefrontal cortex is the most recently evolved part of the cortex and sits at the front of the brain. It is used for making decisions and humans have more of it than any other animal. Although, it is also responsible for negative feelings like guilt, worrying, and, of course, depression.

The prefrontal cortex can be divided into four quadrants. The parts of the prefrontal cortex at the top are known as dorsal, near the bottom is known as ventral, near the middle are medial, and to the sides are lateral.

The dorsolateral prefrontal cortex (bottom and middle) concerns itself with the outside world and planning, whereas the ventromedial prefrontal cortex (top and sides) is vital for motivation and impulse control.

The limbic system, unlike the prefrontal cortex, is much deeper in the brain and has existed in animals going back one hundred million years. This is the emotional part of the brain. It has four regions: the hypothalamus (controls stress), amygdala (key to reducing anxiety), hippocampus (for creating long term memories), and cingulate cortex (helps control focus and attention).

Two other regions in the brain are also responsible for depression. The first, the striatum which has the dorsal striatum and nucleus accumbens, when disrupted can cause the bad habits we often associate with depression – like lack of motivation, impulsiveness and procrastination.

The other region, the insula, mediates our body’s awareness of bodily sensations. If you have depression, you are more like to suffer from chronic pain, because the insula will be more reactive to pain.

Why is Your Brain Like That?

Each brain is different, with different circuits and different sensitivities. You may be more likely to be indecisive, or to rely on social connection. Your brain isn’t wrong, just different. Negative patterns in our circuits can cause our downward spiral into depression.

Our risk of developing depression is down to the following: Our inherited genes; how we were raised as children; our current life experiences and stresses; the type of social support we do or do not have; and random luck!

Our brains are complex and the result of millions of years of evolution. But, our neural circuits can be changed by shifts in our behaviour. With some tuning, we can move away from the pattern of the downward spiral into depression, to the upward spiral out of it.

Worrying is mostly thought based, whereas anxiety has more to do with physical components like bodily sensations (such as an upset stomach) or associated actions (like avoiding a situation). Worrying involves the prefrontal cortex and its interactions with the limbic system, particularly the anterior cingulate, while anxiety involves only the limbic system, mostly interactions between the amygdala, hippocampus, and hypothalamus. In essence, worrying is thinking about a potential problem, and anxiety is feeling it.