Suzanne Lachmann (pictured), a contract psychologist for the FDNY has declared Trump mentally 'unfit for office'

A contract psychologist for the FDNY has diagnosed Donald Trump as mentally 'unfit for office'.

Suzanne Lachmann took to Twitter to share her views on the President, claiming she had met and had 'direct interaction' with Trump, and said her work in determining if firefighters needed to be stood down from action qualified her to make the call.

Lachmann has previously expressed her view in a 2017 article written for Psychology Today, citing an encounter she had with the President soon after his divorce from Ivanka in 1992.

She said when she approached him and introduced herself, he told her: 'Why would I want to talk to you? I wouldn't even let you suck my d***. Look at all the beautiful women here. Don't waste my time.'

Lachmann said in the article Trump was delusional and suffering from a deterioration in his cognitive functioning - things that were directly in contrast to the mental state expected of someone appointed the leader of the free world.

'Mr. Trump cannot uphold the duties of this office because even in his first 100 days, his insight and judgment have disintegrated to the point at which his public statements, accusations and tweets seem delusional,' she wrote.

Lachmann said Trump was 'delusional' and the pair had once met at a party in the early 90s, where he dismissed her and said 'I wouldn't even let you suck my d***' when she tried to introduce herself

Lachmann said in her tweet her work as a clinical psychologist who consulted for the FDNY qualified her declaration that Trump was unfit

'Delusions are fiercely protected by their holders. Not shockingly, Trump feels otherwise, declaring, "I think my strongest asset maybe by far is my temperament. I have a winning temperament".'

'His distorted thinking, disorganized conduct, and erratic, impulsive behavior, combined with his fixation on his own importance directly imperils our safety as citizens of the United States and he must be removed from the line of duty.'

Lachmann told The New York Post she is contracted to the FDNY's counselling services unit and paid by the hour to treat firefighters.

She says she is currently seeing six, and has previously shared letters from the FDNY thanking her for her service, and says she received a placard 'in recognition of the many [firefighters] I've aided'.

Frank Gribbon, a spokesman for FDNY, told the Post Lachmann's tweets should not be associated with her work for the Department.

'It's inappropriate to cite her work with FDNY in social posts that express political views,' he said.