Mental illness affected 43.8 million people last year - that's more than one in five Americans. The Substance Abuse and Mental Health Administration's (SAMHSA) 2013 National Survey on Drug Use and Health shined a spotlight on how extensive the problems are.

More than 15 million Americans over the age of 18 experienced major depression, with more than nine million having serious thoughts of suicide. Suicide was attempted by 1.3 million Americans in 2013, according to SAMHSA.

Only 38 percent of teenagers coping with major depression received treatment; one in 10 teenagers suffered from major depression in 2013.

"It is a serious issue that millions of Americans are needlessly affected by mental illness when they can get effective treatment to restore their well-being," SAMHSA Administrator Pamela S. Hyde said in a statement, according to CBS News. "Now more than ever, people can get the help they need to recover from mental disorders and live full, active lives - they just need to take the first step and seek help."

Many people suffering from mental illness thought they could not afford treatment, according to CBS News. The second reason for not seeking help was thinking the problem could be handled without treatment or just not knowing where to turn.

SAMHSA has an online guide for people to find mental health treatment, and it also runs a 24-hour, toll-free information line: 1-800-662-HELP (4357).