To the Editor:

Soon after the election, one of us raised concerns about Donald Trump’s fitness for office, based on the alarming symptoms of mental instability he had shown during his campaign. Since then, this concern has grown. Even within the space of a few weeks, the demands of the presidency have magnified his erratic patterns of behavior.

In particular, we are struck by his repeated failure to distinguish between reality and fantasy, and his outbursts of rage when his fantasies are contradicted. Without any demonstrable evidence, he repeatedly resorts to paranoid claims of conspiracy.

Most recently, in response to suggestions of contact between his campaign and agents of the Russian government, he has issued tirades against the press as an “enemy of the people” and accusations without proof that his predecessor, former President Barack Obama, engaged in partisan surveillance against him.

We are in no way offering a psychiatric diagnosis, which would be unwise to attempt from a distance. Nevertheless, as psychiatrists we feel obliged to express our alarm. We fear that when faced with a crisis, President Trump will lack the judgment to respond rationally.