Maybe if I give you guys the basics that'll help explain the direction I want to take this.
Memetic Immune Deficiency Syndrome
Like bacteria, memes can be harmful, neutral, or beneficial to their hosts. The most successful memes are not necessarily the ones that are the best for their hosts, but those that are most likely to survive long enough to spread and survive. As such, we cannot assume that a meme -- even a very established one -- is beneficial, or even non-harmful. As a result, our minds have developed defense mechanisms against foreign memes: our memetic immune system.
Like the body's immune system, our memetic immune system is developed over time primarily through exposure to new potential threats. One example of a developing memetic immunity would be someone's exposure to knock knock jokes. At first, they may become severely infected with the idea, but it quickly passes and in the future they're likely to be more hostile to a potential knock knock joke (unless it is a successful mutation).
Some people have stronger memetic immune systems than others. Some have such a strong hostile reaction to new memes that they are unable to gain the benefits from "good" ones, but some people have such a weak reaction to new memes that they are susceptible to constant infection.
My theory is that some types of mental illness are memetic in nature, and that there are people who catch them more frequently and with more dramatic symptoms than average because they suffer from a weakened memetic immune system. If it could be proven to be an underlying cause for certain mental illness infections, it may be possible to identify at-risk people and provide them with the mental tools necessary to identify and eliminate harmful memes from their system manually (much like mildly autistic people can learn to consciously read social cues that others get instinctively). More importantly, it would make it possible to prevent a number of moderate to severe cases of mental illness before they start.
My instincts right now are that the most likely candidates for memetic mental illnesses would be Depression (recurrent, acute, possibly seasonal, not constant low-grade or depression associated with bi-polar disorder); Anxiety; Eating Disorders; Suicidal thoughts and actions; and Phobias.
Potential other symptoms of memetic immune deficiency may be: susceptibility to cults and religions; decreased sense of personal identity; bad/disorganized taste in music; excitability after exposure to movies; increased placebo reaction; and gullibility.
What I'm not saying: I am not saying that mental illness is not a real thing, nor am I denying a biochemical component to mental illness contracted memetically.
So, while that's all well and good from a "bullshit forum post" standpoint, it's nowhere near ready to throw at people who might have the degrees necessary to do research on these kinds of things. I need a more in-depth understanding of memetic theory as it stands now to be sure that I'm using the appropriate vocabulary (where it exists) and that my ideas mesh well with the whole theory, and not just the basic "memes are idea viruses" understanding that I have right now.