And the great dragon was hurled down—that ancient serpent called the devil and Satan, the deceiver of the whole world. He was hurled to the earth, and his angels with him.

Rev 12:9

The notion that a spiritual entity, or entities could influence our thoughts and emotions probably doesn't carry much weight for many people living in modern, enlightened societies. You have to wonder though, how an educated and well developed nation, like pre-WWII Germany, could come under the sway of a charismatic but demented personality. What needs to happen in order for this to occur?

Do you think it's possible for this kind of deception to occur on a global scale?

the whole world marveled and followed the beast. They worshiped the dragon who had given authority to the beast, and they worshiped the beast, saying, “Who is like the beast, and who can wage war against it?”

The beast was given a mouth to speak arrogant and blasphemous words, and authority to act for 42 months. And the beast opened its mouth to speak blasphemies against God and to slander His name and His tabernacle—those who dwell in heaven.

Then the beast was permitted to wage war against the saints and to conquer them, and it was given authority over every tribe and people and tongue and nation. And all who dwell on the earth will worship the beast—all whose names have not been written from the foundation of the world in the Book of Life belonging to the Lamb who was slain.

Rev 13:3-8

I don't want to place too much emphasis on secular theories like "mass formation psychosis", because I think  the root cause is spiritual in nature.

But I think this video clip from Dr. Robert Malone offers a few interesting points to consider - given the very strange times we live in.