In Japan, an estimated 1.5 million people - many of them young men - now live in complete isolation. Some 6,000 miles away, the United States is experiencing its own form of hikikomori.

Work carried out by academics at Kyushu University in Japan has found that a low testosterone level is one of the common metabolic signatures of hikikomori in young social recluses — which is important to note because testosterone levels among young American men are plummeting and have been for years.

The drop now reportedly affects 1 in 4 men in the US.

It’s commonly assumed that testosterone fuels anti-social behavior.

In December, “Avatar” director James Cameron made headlines when he claimed that testosterone is “a toxin” that needs to be worked out of one’s system. Last month, NPR discussed the association between “toxic masculinity” and testosterone. ...continue reading