Less than half of Americans can recognize anxiety. Most people don't know what to do about depression even when they spot it. And nearly 8 in 10 don't recognize prescription drug abuse as a treatable problem.

Those are just some of the findings of a new national survey on issues surrounding mental-health literacy by Michigan State University scholars.

"Our work is designed to help communities think about how to address behavioral health challenges as they emerge, whether that's drug abuse, anxiety or other issues, and the challenges such as suicide that can accompany them," said Mark Skidmore, an MSU professor and co-investigator on the project.

The national survey examines mental health literacy on four major issues: anxiety, depression, alcohol abuse and prescription drug abuse. The work is funded by the U.S. Department of Agriculture and the Substance Abuse and Mental Health Services Administration, an agency within the U.S. Department of Health and Human Services, and administered by the National Institute of Food and Agriculture, within Agriculture Department.

Skidmore said the web-based survey -- which involved nearly 4,600 total participants -- aims to give health officials and policymakers a better understanding of where to target education and prevention efforts for major societal issues such as prescription drug abuse. Public health officials are calling the opioid epidemic -- which killed more than 33,000 people in 2015 -- the worst drug crisis in American history.

According to the survey, 32 percent of all respondents were unable to identify the signs of prescription drug abuse (taking higher doses than prescribed, excessive mood swings, changes in sleeping patterns, poor decision-making and seeking prescriptions from more than one doctor). Those percentages were even more concerning for people aged 18-34 (47 percent) and among all men (44 percent).

"Although great strides have been made in the area of mental health literacy in recent decades," the authors write, "the discrepancies in mental health knowledge, helping behaviors and stigma show the importance of continuing to educate the public about mental health issues."