The Poldark screenwriter Debbie Horsfield has revealed that her postnatal depression helped her write the hit BBC drama and explore the mental health issues that affect its major characters.

Horsfield, who adapted Winston Graham’s Poldark novels, said there is still a hesitation to speak up about mental health problems, even though they can strike anyone at any time. She added that although more public figures are talking about their struggles, the public reaction has often been mixed.

She spoke to the Radio Times of her own difficulties with depression shortly after giving birth when she adapted Poldark, currently being broadcast on Sunday nights on BBC1.

“After the birth of my first child, it didn’t occur to me to talk about the permanent fog I felt I was wading through, let alone consider it a form of postnatal depression,” she said.

“When I eventually confided in a family member, she actually got up and ran out of the room! This was something of a blow – it had taken courage to ‘come clean’ – until I realised the person concerned had probably struggled with that same issue herself and still found it hard to come to terms with,” said Horsfield.

The experience gave the screenwriter “insight into the challenges involved in acknowledging and addressing the stigma and fear surrounding the subject”.

The popular series has been applauded for how it has delved into a number of mental health issues, including post-traumatic stress disorder and bereavement.

Annie Belasco, head of services at Pandas Foundation, a charity that supports people coping with perinatal mental illnesses, said: “Sadly Debbie’s story is not uncommon. We frequently work with parents whose expected joy is overcast with anxiety, stress and depression, which can be unexpected.

“We are grateful to many people like Debbie who open up and talk about their lived experiences as it encourages others who may be struggling with their perinatal mental illness to seek the support they need,” said Belasco. She called on maternity services to discuss perinatal mental health from conception through to birth and beyond.

Jane Caro, programme lead for families, children and young people at the Mental Health Foundation, said: “The first weeks and months of life are incredibly special and important for both mother and baby. Postnatal depression that remains undiagnosed and untreated can harm their developing bond, so it is crucial for all women during pregnancy and after birth to have access to the right support.”

Caro added that provision for women with postnatal depression is inconsistent across the country and called for increased investment. “This will ensure that the next generation of children get the best possible start in life.”