An autistic teenager who started writing thank you cards to health and care workers to deal with his anxiety about the pandemic has now sent almost 600 cards and is aiming for 5,000.

Patrick Joyce, 16, from Glasgow, began writing to healthcare staff in mid-January to thank them for helping Covid-19 patients.

He has since received many responses to his cards, including from former Irish taoiseach Leo Varadkar.

Patrick’s mother, Indra Joyce, said he had been struggling with severe anxiety stemmed from the pandemic, but writing the letters has “transformed him”.

“He was having a complete breakdown. I had to get emergency (child and mental health services) support,” Ms Joyce told the PA news agency.

“He was so fixated on the Covid stats and particularly the deaths.

“He’s now a happy boy! It has transformed him. Paddy feels useful and that he is making a difference.”

Former taoiseach Mr Varadkar returned to medicine last year as a doctor to aid the response to Covid-19 in Ireland.

Writing in response to Patrick – also known as Paddy – Mr Varadkar thanked the teenager for his “lovely colourful” card and said the letter is now sitting on his window sill in his office.

Ms Joyce is Patrick’s full-time carer after his father died in 2014, when he was 10.

After a traumatic birth, Patrick was diagnosed with various cognitive disabilities, including global developmental delay (GDD) and autism.

“Patrick is 16, but due to GDD he is more like a seven to eight-year-old,” Ms Joyce said.

“But throughout all his struggles and difficulties, he has always been sweet-natured and he gets upset when people are sad and wants to hug them to make it better.”

The family’s card-writing journey began last month when Ms Joyce posted to Twitter asking for the names and hospital addresses of NHS workers, so Patrick could start penning the letters.

The post was warmly received and Ms Joyce said her son has since been averaging between 10 and 50 cards per day, with him writing and his mum filling the envelopes.

“It depends how keen he is and how much energy he has, and if the footie is on,” she said, noting Patrick is a keen Everton fan.

Ms Joyce said she expects him to exceed his 5,000-card target, adding: “Once he decides something, he’s fairly determined to stick to it.”

Speaking during children’s mental health week, Ms Joyce said she would recommend parents to find similar activities if their child is struggling with anxiety about the pandemic.

“If it helps (I’m) all for it” she said.

“I knew Paddy loved writing … others might find solace in art, or fitness, or music, but I support and help him too, so it’s also helped our relationship.”

If you would like to share the name and address of a health worker so Patrick can send them a card, you can send Ms Joyce a direct message via Twitter with her handle @Indra68.