I was with you till the last sentence. Depression is not a negative or sad feeling about yourself, it is a repressive cloud that is a result of negative conditioning over a long long period of time or unbalanced chemical reaction in your brain. My mother suffers from / afflicted with clinical depression, she always had a short fuse and irrational responses to stress and negative stimuli, she was a contradiction, always looking for a fight but avoiding negative stimuli at the same time, knowing now what we didn't know when I was growing up, certainly connects a lot of dots for me about her behaviour. Depressive states are as bad as it gets for some people, there is a range of depression that a person can suffer from, it's never a gift. Wall flowers / loners are not necessarily depressed, they could be anything from perfectly normal to having some sort of medical condition.
The good thing for your youngest daughter is she is learning about shitty human behaviour, while being teased by your older daughter, she will use that knowledge later in life, she will be stronger for it. It will be part of her life tool survival kit.
I agree with you Extreme Depression can be very unfortunate, and I did not mean to make light of it. I think most of us have been depressed at one time or another, and yes people self medicate those moments and dig themselves into a deeper trench. Alcohol is a perfect example of this.
I do think the extreme cases are very rare and probably more of a result of some sort of a chemical imbalance. The problem I see with those in my life who have had depression, and sought out psychologists, is that I often see them making the exact same mistake over and over again. Sometimes not taking responsibility for their own mental health, thinking that someone else will take their problems away. We can argue about how good the meds are, my uncle was on prozac for a long time, and like all chemicals, the brain eventually gets used to it... and when you get off those meds you are worse than when you started. He eventually took his own life.
That said, I remember him preaching to me giving me life advice, not being able to take any himself. He would talk about how he made sure to get the 1st floor in the apartment building because he hated being stuck on elevators with people. Then he would complain about how lonely he was. He would give me advice like, "Never marry an ugly woman, you will be stuck looking at her for the rest of your life.". The rest of my family avoided him, because he acted like he was an expert on life, while we all knew he avoided life like the plague.
This fear he had of talking to strangers, judging others by how they looked, was the same judgments he was left with when he looked at the mirror himself, and he wasn't going to win any beauty contests.
His doctor was so perplexed with his constant declarations that life is pointless, that he finally prescribed morphine for him.... well guess what, my cool uncle said that pills were making him feel funny, and he gave me his prescription. That started the 18 year old me on on another 20 year opioid addiction.
Some of these psychologists keep asking their patients to retell them their previous traumas, this method of therapy is now frowned upon as all you are asking for is the people to retraumatize themselves every time they retell their story, we will often make it worse with each retelling. Creating an identity and a victim mentality. The only person that profits is the psychologist who has you booked for years and years reminding you of your frailties.
The new approach is to do things to get past those moments, to instead substitute those patterns for positive memories, to forgive the transgressors and leave it in the past. You are not a victim, and your future can be a happy canvas of your own making.
I think like most professions, there is this huge lobby to preserve their own usefulness. What good is a psychologist that heals her patients, she now has to find new ones. What good is a prison that actually reforms the convicts? What good is a legal system that rehabilitates criminals instead of showing them the revolving door. A University Organic Chemistry professor asked his students "How many of you are here to find a cure for cancer?", many students raised their hands, and he replied to them sorry... that is not what you will do in this field, 99% of all jobs are about patenting and selling chemicals at a profit. Cures don't make money.
So with all the help that my uncle was getting from doctor after doctor, I can't say that any of it was much help to him... none of it seemed to help him have new outlook on life, or change his entrenched toxic opinions of others, it just seemed that they were booking him to bill OHIP. Giving him chemicals that found their way to his nephew. I am guilty for taking them, but if I knew what I know now... I don't think any of it made much progress with him. He was just a number in the system.
EDIT: The point I am trying to make is that a lot of these folks are told that they can't do anything about it, that they don't have the power. Well, we know that the brain is very plastic and adaptable, if you practice new behaviors, new methods of thinking, you may actually have a lot more power over your condition than a system that is designed to tell you that you need them more than they need you. The problem with this is that it gets harder the older you are, if these problems were caught earlier and corrected it would mean less trauma for all involved. However, a lot of the practitioners see the problems early and instead of creating new patterns for coping, they medicate, they re-enforce the sickness and futility of the condition.
I really think it is irresponsible to tell a person that they have no control over their own mental health. To make them subservient to others for their peace of mind. Yes some people have damage to the brains, but there have been plenty of car crash victims, who went through hell and were able to adjust with enough rehabilitation and effort. I think this is also true for chemical imbalances in the brain, telling someone to avoid certain foods is not very billable. We know that some people are sensitive to what they consume and that includes medications and alcohol.
Sadly, a lot people that have these conditions are told that everything is beyond their control, that they must just stick to their prescriptions and appointments... and there is never really an end in sight.