Depression, still a mystery

Happy Saturday everyone :D

I am actually working on a project for one of my courses to see how mouse models are used to model depression and whether the gut bacterial composition plays an influence. Hence, that explains my last week's post with regards to bacteria and depression. Well I wanted to learn  more about depression. It is in a way something dear to me because I know multiple people who have struggled with it. One day, I was talking to one of my TA's and couldn't help but notice the scars on her wrists. It's scary to think about but some people look so put together on the outside, yet are in a huge amount of pain on the inside :( I wouldn't say I've ever had clinical depression myself, but I have struggled with it mild depression on and off in my teenage years.

Anyways, I was surprised to learn that scientists still don't know what causes depression. You think they would extensively research it since 20% of the American population (>30 million adults) experience a clinically significant episode of depression during their life. Wow, that's like 1 person in every family.

What is it?

What is depression definer to be? It is a disorder of emotion regulation along with repetitive negative thinking and biased attention to negative information. However, there's no clear cut definition as people experience various levels of severity of depression. Some patients can have a few depressive episodes and have a rapid remission while for others it is a prolonged, remittent illness. Some common symptoms of depressive include:

*agitation, restlessness, irritability, difficulty concentrating
*becoming withdrawn or isolated, losing interest or pleasure in favorite activities
*changes in appetite along with weight gain or loss
*lack of energy, fatigue, sleeping too much or trouble sleeping
*feeling of hopelessness, helplessness, and worthlessness
*thoughts of death or suicide

What causes it? 

Brain imaging studies have hypothesized changes in the hippocampus, amygdala, and prefrontal areas of the brain to play a role in the emotional and cognitive processing in depression. These areas have function related to memory formation and fear. Unfortunately, what is noted are merely correlations and not necessarily the cause. 

Another hypothesis involves the hypothalamus- pituitary- adrenal (HPA) axis imbalances that have to do with cortisol & norepinephrine (stress). Alternatively, it is possible that the gut microbiota also plays a role.

The most prevalent hypothesis, is that there is an imbalance in serotonin levels with individuals with depression having low levels of serotonin. Serotonin is a neurotransmitter, meaning that it is a molecule produced at the end of one neuron and can activate the adjacent neuron. Hence, it is involved in the relay of nerve impulses and messages. Specifically serotonin is known to regulate mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation, and some social behaviors. 

How is it treated?

As many know, antidepressant drugs are present on the market. Apparently, 6 out 10 patients find that the first drug they take relieves the symptoms of depression. The others need to play around with different drugs and find out what works best for them. The symptoms usually take about 9 months to subside. 

Most drugs target serotonin, specifically the mechanisms responsible for their reuptake. These drugs are referred to as SSRIs (selective serotonergic reuptake inhibitors). So by inhibiting serotonin reuptake, more of the serotonin is present between two neurons and can produce more communication between these neurons. SSRIs are generally safe but all patients have at least one side effect. These include constipation, daytime sleepiness, diarrhea, dizziness, dry mouth, headache, nausea, sexual problems (bummer!), shakiness, trouble sleeping, and weight gain. In rare cases a serotonin syndrome can occur where there is too much serotonin. Symptoms of this include restlessness, hallucinations, rapid heartbeat, increase body temperature, muscle spasms, nausea, vomiting, diarrhea, and changes in blood pressure. Every drug is a double edged sword :(

What are some natural treatments?

*Exercise
*Good sleep
*Seeking out activities that bring you pleasure
*Volunteering
*Group activities
*Talking to someone
*Being around positive and caring people ;)
*Potentially probiotics

It is very unfortunate that depression is so common and I don't know if targeting serotonin is the best way. I'm also a bit disappointed that it's not well studied and believe that there should be much more focus on research with regards to depression. 

What are your thoughts on depression? Have you ever experienced it or known someone who has gone through it?