Psychologists break down the mysteries of Donald Trump's handshake

Italian Prime Minister Paolo Gentiloni shakes hands with with US President Donald Trump at the G7 Taormina summit: Sean Gallup/Getty Images
MoreDonald Trump’s handshakes have become something of an international curiosity – and now, psychologists have broken down the “tactical” move.
The president’s unique grip raised eyebrows during his visit to a Nato summit last week, where he appeared to painfully twist the arm of French President Emmanuel Macron.
Ahead of the