The surprisingly high-risk, high-cost medical condition that is... loneliness
"Look at all the lonely people," instructed the Beatles, pondering where they all came from. Elvis Presley opined that he was so lonely he could die. Back in 1802, William Wordsworth wandered lonely as a cloud.
Perhaps because of its enduring poetic attraction, loneliness in the public discourse is generally regarded as a sad, but transient, state. Among the young, it is seen as a temporary consequence of adolescent hormonal moodiness, or, worse, an artefact of fey existential posturing.