The tragic news of Robin Williams's death by apparent suicide on Monday has again reignited a larger conversation about the need to eliminate the social stigma still surrounding depression and mental illness. It's a conversation that seems to keep resurfacing around tragic incidents over the past couple of years, so it's worth asking whether the stigma is at all getting smaller.

Unfortunately, there aren't very many rigorous polls capturing American attitudes toward diagnosis and treatment of mental illness. There are some signs of changing attitudes, though.

A 2010 study in the American Journal of Psychiatry showed that Americans, between 1996 and 2006, developed a greater awareness of the neurobiological basis of mental illness and became more supportive of medical treatment. Despite that, the social stigma associated with mental illness is still significant— and in some instances, actually increased from 1996 to 2006, according to research led by Indiana University professor Bernice Pescosolido, director of the Indiana Consortium for Mental Health Services Research.

Analyzing responses to the General Social Survey in 1996 and 2006, researchers found that people have become more likely to support the idea that someone with depression should see a psychiatrist (up from 75 percent in 1996 to 85 percent in 2006). People also gave a greater endorsement of psychiatric treatment for alcohol dependence, up from 61 percent in 1996 to 79 percent in 2006. There was also a greater understanding of the neurobiological causes of mental illness, though there was less understanding when it came to alcoholism; respondents were actually more likely to think alcohol dependence was an indicator of a person's "bad character," increasing from 49 percent in 1996 to 65 percent in 2006.

Those improvements in understanding mental illness, however, didn't help reduce the social stigma, researchers found. People were more likely to say they didn't want an alcoholic to marry into the family (up from 70 percent to 79 percent) or have someone with schizophrenia as a neighbor (up from 34 percent to 45 percent). Most in 2006 also said they were unwilling to work closely with someone who had schizophrenia (62 percent) or alcohol dependence (74 percent), and most thought people with either illness would likely be violent.

"There was no support that greater scientific understanding translated into reduced prejudice in the United States or elsewhere," Pescosolido wrote in a more recent March 2013 review of research into the social stigma around mental illness. Reducing the stigma, she points out, will depend on a better understanding of the social and cultural factors shaping it.

We do know that there has been a recent increase in those receiving mental health services. About 34.1 million adults (or 14.5 percent of those 18 or older) received mental health services in 2012, more than any other year in the preceding decade, according to the 2012 National Survey on Drug Use and Health.

And we also know that there are still major barriers to care. The cost of treatment was the highest barrier for those with unmet mental health care needs, according to the same 2012 survey. Most seeking outpatient treatment for mental health services faced anywhere between $100 and $500 in outpatient costs, according to another government survey tracking 2005-2009 data. But you can also see that concerns about stigma, like what a neighbor or an employer might think, were a factor: