Sociologists and psychologists are increasingly worried about the narcissistic epidemic spreading in our world, and for very good reasons (http://www.narcissismepidemic.com/). The issue is not that we see more self-centered teenagers, taking lots of selfies and spending time in the gym, as the popular belief would be. The reality of this problem is far more serious and has severe than one would think.
Let's start, firstly, by defining briefly this disorder and its implications. The most important thing to note is that this mental illness is not singled out in a set of precise symptoms that are strictly defined, recognizable and treatable. The first most important issue to note is that this disorder manifests on a wide and varied range (http://humanmagnetsyndrome.com/). At the bottom of this scale we have what psychologists call "healthy narcissism", i.e. a good dose of self-esteem and the tendency to care towards oneself. There is nothing problematic there. On a slightly higher scale we would have what most people popularly define as narcissistic, i.e. a person who is overly concerned with themselves, their image and presentation. This would include behaviours such as selfies addiction, as mentioned above. Although this tendency is not healthy, it also doesn't have grave consequences and its affect on society is but moderate.
We run into serious problems when we start upping the scale, into what is technically defined as pathological narcissism. This is a personality disorder characterized by (according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, 1994):
1. An exaggerated sense of self-importance (e.g., exaggerates achievements and talents, expects to be recognized as superior without commensurate achievements)
2. Preoccupation with fantasies of unlimited success, power, brilliance, beauty, or ideal love
3. Believes he is "special" and can only be understood by, or should associate with, other special or high-status people (or institutions)
4. Requires excessive admiration
5. Has a sense of entitlement
6. Selfishly takes advantage of others to achieve his own ends
7. Lacks empathy
8. Is often envious of others or believes that others are envious of him
9. Shows arrogant, haughty, patronizing, or contemptuous behaviors or attitudes
Traits 7 and 6 are particularly preoccupying among the many characteristics. A more accurate specification made by Sam Vaknin, world expert on the disease, now redefines 7 to be a 'lack of emotional empathy', but this distiction will not serve us for the moment.
What traits 6 and 7 mean is that individuals with this personality disorder essentially do not consider other people as beings in their own regard - with their own personal desires, needs, feeligs - but rather as objects for their use. This is particularly problematic given trait 1, 2, 3,4, 5, which mean that other people will be used by this personality to achieve unrealistic success goals at unpredictable costs.
Consider now what happens when such a person becomes a leader, or a person with a powerful position in society. Imagine that they are given the rensposibility to make important decisions for companies, cities, nations. What would happen then? We know these people do not have the interests of others at heart. Their only concern is their grandiosity, however that may be defined for them specifically. They will in fact resentlessly step over the interests of others for their personal gains, no matter the cost. This seems a recipe for disaster. And yet, this is exactly what is happening in our world today.
Not only do such individuals exist and are wide-spread (according to the statistics they comprise about 1% of the population, although according to some experts it is even more), but they do in fact take on rols of leadership in our society, both in the workplace, in the families and communities, in religious groups as well as in politics, media and any other areas that matter. The above mentioned gloomy scenario is in fact already a reality.
But it doesn't end there. We have not travelled to the top of the spetrum of the disorder yet. Pathological narcissism is already a serious enough ailment on its own, but yet graver forms of the disease exist. Individuals with this disorder can take all the way to malignant traits (where they are completely ruthless in the way they use others for their interests) to sadistic (where they actually feel pleasure in creating suffering in others) and psychopathy and sociopathy, with all sorts of other associated disorders such as borderline, hystrionic etcetera. This means that the disease is not limited to utilizing others for the sake of personal gain - as the classic leadership scenario described above - but it can go as far as hurting others for the sake of gaining pleasure and creating devastating damage.
Given the above description and our current situation in the world one might be tempted to think that this latter, graver form of the disorder is probably more rare and secluded, and these kinds of individuals do not go free and undisturbed for too long. Unfortunately we couldn't be more wrong by concluding this.
Sadistic psychopathy as a disease is manifested in our reality on a daily basis, and everywhere. However, whereas the pathological narcissistic form of the disease needs to appear somehwat acceptable in order for people to support it in its leaders - and thus is often camouflaged in great charisma and standing appearance - sadistic psychopats cannot simply get away by having a great appearance, for their acts entail such cruelty that they would eventually be stopped. That is why they work in hidden circles, in places that are discreet from the eyes of the public and where people normally would not look.
One such circle is the animal industry. Sadistic practices are carried on animals in all sorts of ways. As there are no clear laws protecting animals, and most importantly there is no-one enacting these laws consistently on their behalf, other than the smaller scenario in which people who actually care about the animal are involved - sadistic mentally disturbed people can often act undisturbed in these environments, treating with extreme cruelty the animals. There are exmples of this in the animal industry for food and clothing products, the vivisection labs, and animal entertainment industry (1,2,3,4). You can watch a few examples here (https://www.youtube.com/watch?v=2w7TCmJUD7g).
Other large groups of people that goes under the radar when it comes to human rights and legal protection are minority groups, prisoners, people who live in poverty, and children. These are greatly targeted by sadistic psychopaths as well. Pedophile rings and cults and sects that perform ritual abuse on children are quite widespread in the Western world (see for instance 5,6,7). Chid slavery is a reality more common in third world country, where sex slavery utilizes children both in local brothels as well as for sex tourists from the West (8,9,10). Orphanages are anohter often targeted unprotected group (11). Prisoners, where sadistic cops can often act unmonitored, minority groups such as lgbt, african americans, are often targted as well. War victims as well, are often targeted by sadic soldiers with torture, rape and other sadistic practices.