"an increase in mass hysteria, in which large numbers of people share psychological or physical maladies that have no apparent cause, can be attributed to: "

It can be attributed to "social media".

Mass hysteria is the normal term used to depict a circumstance in which different individuals all experience the similar hysterical symptoms – either from a phantom ailment or a mysterious occasion. Social media is turning into a necessary piece of life online as social sites and applications multiply. Most conventional online media incorporate social parts, for example, remark fields for clients. In business, social media is utilized to advertise items, advance brands, interface with current clients and encourage new business.