Kate, patron of addiction recovery charity The Forward Trust, said addiction was “a serious health condition” and “not a choice”.
Her message of support for the Taking Action on Addiction campaign was released on video for the start of Addiction Awareness Week.
“Addiction is a serious mental health condition that can happen to anyone, no matter what age, gender, race or nationality,” she said.
“As patron of The Forward Trust, I have met many people who have suffered from the effects of addiction.
“Attitudes to addiction are changing. But we are not there yet, and we need to be. Still the shame of addiction is stopping people and families asking for help and people are still tragically losing their lives.”
The Forward Trust’s campaign hopes to reframe perceptions of addiction, build awareness of the causes and nature of addiction, improve understanding, reduce prejudice and enable more people to get help.
“We as a society need to recognise that the only way to help those suffering is to try to understand what has led them to addiction, to empathise with them and to be compassionate to their struggles,” Kate said.
“And so today, during Addiction Awareness Week, I want to share a message of support to those who are continuing to suffer.
“Please know that addiction is not a choice. No one chooses to become an addict.
“I want you to know that this is also a serious health condition. Please do not let shame hold you back from getting the help you so desperately need.
“The charities leading the Taking Action on Addiction Campaign, along with others, are working across the country delivering life-changing work to help people recover and move forward.
“They are here for you. So please ask for help. I know this was not a choice. Recovery is possible.”
In the video, Kate appears to be speaking from home as she sits on a sofa with framed family photographs behind her.
Mike Trace, chief executive of The Forward Trust, said: “Addiction Awareness Week speaks directly to people affected by addiction, offering support and understanding so that more people ask for and receive help.
“At a time when addiction is growing across the UK, it is crucial we build awareness of its causes and act quickly to stop this tide, to get in early to reduce the impact on families and children, and make sure that people are able to access the support and treatment that we know makes recovery from addiction possible.”