Miliband attacked celebrities who poked fun at mental illness, including Jeremy Clarkson and Janet Street-Porter.
In his speech in London at The Royal College of Psychiatrists he said: "One in four of us will have a mental illness at some point in our lifetime. It is the biggest unaddressed health challenge of our age.
"There are still people who abuse the privilege of celebrity to belittle others."
Miliband added: "Janet Street-Porter says depression is 'the latest must-have accessory' promoted by the 'misery movement'.
"And Jeremy Clarkson, who may have at least acknowledged the tragedy of people who end their own lives, goes on to call them "Johnny Suicides" whose bodies should be left on train tracks rather than delay journeys.
"It is attitudes like these that reinforce the stigma that blights millions of people's lives, and holds our country back," said Miliband.
Miliband also went on to say: "We can't prevent all mental ill-health, there are not cures for all conditions, but we can help change the culture in our country."
Nigel Wilson, group chief executive of insurance provider Legal & General, this morning challenged employers to do more about mental health in the workplace: "We look after almost 200,000 employees in all sorts of different sectors, and know that if we intervene early, we can get 74% of people back to work in a year.
"Specialist treatment like Cognitive Behavioural Therapy can help people not just to come back to work but to stay at work in the first place."
