Mhairi Black has revealed for the first time that she has attention deficit hyperactivity disorder (ADHD) and is taking Ritalin to help tackle the condition.

The former SNP MP told an audience at a performance of her sold-out Edinburgh Festival Fringe show, ‘Politics isn’t for me' that she was diagnosed in 2018. 

The ex-deputy leader of the SNP Westminster group mentioned her ADHD in the context of rumours on social media that she was a cocaine user.

“If I was doing cocaine, the worst that would happen is I'd function a bit better," she joked. "But I don't need to, because I get prescribed Ritalin. I get prescribed literal speed."

READ MORE: Mhairi Black to perform comedy show at Edinburgh Festival Fringe

During the hour-long comedy show, she also made a number of jokes about her relationship with the rest of the SNP group at Westminster, including Joanna Cherry, and made gags at the expense of JK Rowling and Alex Salmond.

Ms Black also jokingly described the Serjeant at Arms of the House of Commons as a "c*** with a sword."

The former MP also re-opened a feud with Scottish Secretary Ian Murray, accusing him of bullying her despite knowing she had health issues. 

The row dates back to October 2017 when an article in The Times pointed out that she had voted in only one-fifth of divisions since June of that year.

Mr Murray raised her voting record during a vote in 2018 when the SNP abstained on the third reading of a Tory Budget.

Just days before, Ms Black had written a column for the Daily Record where she accused Labour of being the “architects of austerity” and claimed they were “happy to stand alongside the Tories".

After the SNP did not vote, Mr Murray tweeted Ms Black asking: "Did you vote against the Tory budget last night @MhairiBlack? To make it easy for you the answer is no you didn’t.

"Maybe you should turn up a bit more often. Worst attendance and voting record in Parliament."

At the time, she replied by linking to an earlier article that outlined the health issues she had suffered from including stomach problems and the norovirus.

The MP also pointed out that she had a sick note from the doctor and could not travel to her work in Westminster due to illness.

READ MORE: Mhairi Black blames bouts of sickness for voting record

Mr Murray responded directly to Black and said: "I'm genuinely sorry you’ve been ill but I was referring to your Daily Record article where you accuse Labour of backing the Tories when the SNP didn’t vote against the Tory budget the very same day of the article [sic].

"You and your colleagues voted on amendments less than an hour before."

Ms Black told the audience at the Gilded Balloon, her doctor at the time had told her she needed to “get away from that environment, take a good bit of time to heal” and they could then “start building different boundaries and strategies that will help me cope".

“I went away and took my time off, but I couldn't actually relax, because very quickly I started getting pelters off of folk.

"I can expect it off Twitter and all the rest of it, but there were actual politicians who were just putting the boot in to me. Saying 'Ah, she's lazy. Look at her voting record. That's terrible. She's no representing her constituency right; there should be a recall.'

"It just kept going and going.

“In particular, our current Scottish Secretary, Ian Murray, him and [former Labour MP and now Labour MSP] Paul Sweeney were two of the main ones who, even though I had been to them and their whips had spoken to them and explained that I was actually off ill, Murray didn't mind, they carried on just putting the boot in anyway.

“And it started basically giving permission for this narrative that I'm lazy, that I'm not up to the job and all the rest."

READ MORE: Mhairi Black to stand down as an MP at the next election

Ms Black added: “And the truth is, I've no get anything funny to say about this, right? It was s***. It was really horrible to experience, and it's bad enough when you're off with poor health, but then when somebody's just rubbing salt in the wound, it makes it so much more difficult for you to be able to heal and heal in a timely fashion.”

Mr Murray and Scottish Labour were approached for comment.