"There should be no shame in discussing or seeking help for treatable illnesses that affect too many people that we love," he said in opening a White House conference on mental health awareness.
"We've got to get rid of that embarrassment; we've got to get rid of that stigma. Too many Americans who struggle with illnesses are still suffering in silence rather than seeking help," Obama said.
The conference's main goal wasn't to start a conversation but to "elevat[e] that conversation to a national level, and bring mental illness out of the shadows," he said.
The conference was convened nearly six month after December's mass shooting at an elementary school in Connecticut by a man diagnosed with a form of autism, a neural development disorder rather than a mental illness.
Obama assured the audience that the majority of those with a mental illness are not violent.
People living with mental health challenges need to know they're not alone and "we've got to be making sure that we're committed to support those fellow Americans, because struggling with a mental illness or caring for someone who does can be isolating. And I think everybody here who's experienced the issue in one way or another understands that," he said.
One in five adult Americans each year experience mental illness, and young people also are affected at a similar rate, Obama said.
"So, we all know somebody -- a family member, a friend, a neighbor -- who has struggled or will struggle with mental health issues at some point in their lives," Obama said.
Two ways that the mental health system could improve, Obama said, such as doing a better job recognizing mental health issues in children and make it easier to receive help, and ensuring treatment is available when people are ready to seek it.
For many who suffer from a mental illness, "recovery can be challenging," Obama said. But what can give them strength is the knowledge that they are not alone.
"You're surrounded by people who care about you and who will support you on the journey to get well," he said. "We're here for you, and that what this conference is about, why these issues are so important."
Near the end of his speech, a man in the crowd yelled, "Thank you, Mr. President."
"You're welcome," Obama said.
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