The derealization of the world

becomes particularly evident from the '60s onward.

Drug use is not the cause. Drug use is a symptom of a receding world and of a facile (chemical) attempt to reestablish connection with something beyond fugitive appearance.

The paradox: loss of metaphysical orientation does not increase contact with reality (as science promises) but the opposite. When physics supplants metaphysics, the world is emptied of meaning, becomes insubstantial. Science zombifies world.

Consumerism transforms the world into a garbage dump of disposable things and images. Disposability contributes to the sense that "nothing is real."

Like science, photography promises greater intimacy with reality but transforms reality into images. It virtualizes the world.

The demythification/demystification of the world undertaken by modern sociology turns the world into an ideological mirage. The demythified world shatters into fragments experienced in bewildering isolation from each other. (Christopher Nolan's Memento.)

This may account for why "identity" becomes a postmodern fetish. 

Unable to participate in a shared, consecrated reality, the postmodern subject compensates by sacralizing the self. However, flimsy postmodern identities resting on nothing more than narcissistic conceits do not yield sufficient existential assurance. Instead, they tend to induce "imposter syndrome." 

The derealization of the world and the self go hand in hand. They are aspects of modern mass psychosis.