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Catherine, Princess of Wales, has called for "humility and compassion" towards those struggling with addiction.

The 42-year-old royal - who is slowly returning to public duties after completing a preventative course of chemotherapy - finds it "heartening" to see the progress made in "ending the stigma" surrounding such issues and urged people to show support to those in need and offer them a "shoulder to cry on".

In a message written in support of Addiction Awareness Week, Catherine wrote:

“Addiction is not a choice. It is a serious mental health condition that could affect any one of us.

"It has been heartening to see that progress is still being made to end the stigma surrounding those battling addiction. For too long, many have suffered in silence, harbouring feelings of shame and guilt about their condition, despite their vulnerability.

“Everyone suffering from addiction is another human being, with a story of their own, which many of us don’t understand or see.

“It is not our place to judge or criticise, we must take the time to sit by someone’s side, learning the values of love and empathy.

"Being a shoulder to cry on or an ear to listen, these simple acts of kindness are crucial in breaking down the misunderstandings that so many face.

“Addiction is not a choice. It is a serious mental health condition that could affect any one of us. By acting with humility and compassion we can all make a difference and support those who are suffering.”

Catherine - who is patron of the Forward Trust, which supports those in the criminal justice system to manage and recover from their addictions - insisted everyone has a part to play in tackling addiction.

She concluded: “Many charities up and down the country are guiding individuals and families through the toughest of times. But they cannot do it alone. It is up to each and every one of us to change the way we think about and consider the many people coping with addiction.

“Because recovery is possible.”

Last year, the princess - who has three children with husband Prince William - visited HMP High Down men's prison in her role as Forward Trust patron

to look at ways of making the visitor experience more positive for families, in particular children.

She sat with her hands on her knees for a check by drug detection dog Penny and was impressed when shown the black Labrador has been trained to sit very still if she detects drugs, rather than barking.

She said: "Amazing. It's incredible, it's very calm and controlled. It's not intimidating."

The princess was told about the programmes offered to help the prisoners with their addictions and spoke to a group of men whose addictions started the journey that ended with them in prison.

She said afterwards: "I asked one of the guys, 'Would you have liked help [with your addiction] earlier?' And he said, 'Yes, but I didn't know I needed it.'"