Depression is not nice
At least with other unwanted thoughts/feelings (like worry, anxiety, resentment, confusion, blaming, guilt), there is some energy, some desire to do something about it. With depression, even though you may not "like it," it's often hard to muster any energy to take action to change it.
Some people can't see "green" (fortunately for them)
Some people, although they "understand" the word depression and can even recognize its symptoms in others, they have no direct experience of it themselves. My father had major problems with depression (he was bipolar). My mother, in contrast, was the polar opposite (LOL). One time I did my best to describe and simplify to my mother the thoughts and feelings someone would likely have when they were depressed. She was silent for about thirty seconds, mulling over what I had said. She replied, "Maybe I felt that way a few times for about ninety seconds. But then I thought of something I was grateful for and it disappeared."
Psychological studies have shown a tendency toward getting depressed is inheritable. I suspect that I may have gotten some of that from my father (perhaps combined with a tendency the other way from my mother).
"Enchanting" is a technique I stumbled onto/invented that dissolves depression. My evidence for this is not only my own experience, but also the positive feedback from several clients who were depressed and used it. (I doubt that any psychological studies that have been done yet to see how effective enchanting would be for a random selection of people suffering from depression).
But it's simple enough to test for yourself (it also is effective in undoing other unwanted feelings). And there is no downside, like there often is when using anti-depressant drugs. Check it out: Enchanting.
Of all the various psychological disciplines, cognitive (behavioral) therapy ( CBT) has the most scientific validation for effectiveness. I highly recommend the book Feeling Good: the New Mood Therapy by Dr. David Burns. And he's just written a new book (2020) Feeling Great: The Revolutionary New Treatment for Depression and Anxiety. I haven't read this one yet (as of April, 2021).
A simple way to tap into the power of CBT for yourself is with the Ten-Minute Cognitive Workout. This is part of my daily routine.
Although Byron Katie's approach is broad-spectrum (it can be used for any issue that causes suffering), it can also focus in on depression (especially if you can identify any thought or belief that under-pins or is associated with your depression. Highly recommended.
Resisted fear and lacking integrity
The old habits of resisting fear or not prioritizing Now-Next integrity and Oneself-Others integrity can contribute to feeling depressed. Take the tests at Quizzing for Life and Fun to assess how you're doing in these areas.
Keeping away from the cliff
For myself, if I don't keep myself well rested or I eat poorly, I am more vulnerable to feeling depressed. Review the NFS toolkit.
When considering a solution for depression, many will first consider consulting with a medical/psychiatric doctor and/or using prescription drugs that target depression. In contrast, I will consider this option to be more of a last resort.
One concern I have about using drugs is that they often mask (or allow us to ignore) a more fundamental issue/cause that would be much more valuable to address if we could and did. And second concern is that many such drugs also create additional mental/physical costs and risks that a mental-psychological approaches rarely have. A third concern is that we can be inappropriately reliant on our prescription provider and we also incur the regular costs of buying the drugs.
That said, prescription drugs have their place. I am very happy that we have them. I have had a few clients who told me that Prozac (or another anti-depressant) saved their life. Especially if someone had recurring suicidal ideas, then I would seriously consider anti-depressant prescription drugs as an option.
Modafinil as a possible anti-depressant
At 76 years old (April 2021), I only take two "prescription" medicines. I put the word prescription in quotes because I don't have a prescription for them (even though I could probably get one, if I really needed to). The two drugs I take are metformin and modafinil. The reason that I don't go out of my way to get a prescription is that I have researched these drugs so well that I am confident that I know more about them than at least 90% of doctors do. Additionally, they are easy enough to get without a prescription.
Metformin is FDA approved for diabetes. I don't have diabetes. Regardless, enough studies have been done with metformin to give strong indications that it is an anti-aging drug. My use of it is called "off-label" use. Currently the FDA does not allow drug companies to apply for drug approval for drugs that are anti-aging (that probably will change within a few years). This is true even though aging itself has recently been recognized as a disease. See Are you getting ready to leave (life)?
Modafinil is FDA approved for narcolepsy. I don't think a doctor would diagnose me as narcoleptic. Nevertheless, I have a few symptoms. For example, if I am sitting in an all-day seminar I will have to stand up from time to time at the side of the room to keep from dozing off in my chair (regardless of how engaging the seminar is). I am usually the only one who seems to need to do this.
More than 95% of people using modafinil around the world are using it off-label. It's considered a "smart drug," which provides focus and a calm level of energy. It can also act as an anti-depressant for some. Whatever side effects it might have are well-documented, none of them very serious. Personally, I don't experience any side effects. I don't need it as an anti-depressant. I use it regularly because it's quite effective in helping me to maintain a sustained level of energy/focus (which makes both my Now and my Next happy). It also seems to help me to have better and more regular sleep.
A friend used modafinil for depression
A good friend got triggered into a deep depression. I asked if she'd be willing to try 100mg modafinil, just half a tablet (which she took early in the next morning). She completely recovered from her depression by the morning after that.
Drugs affect people differently
Doctors know this and you should know this. There was one point where I decided to experiment with modafinil...after I did my research. Only then, and step by step, I decided that the benefits definitely outweighed any possible costs for me. You would have to do the same for yourself, whether with modafinil or any other drug or anti-depression approach. Your #1 responsibility is to take care of yourself.