The contestants on “Celebrity Jeopardy!” were stumped in the fall when asked about the new “3-digit national hotline phone number for suicide prevention” in the United States, which debuted last July.

“What is 311?” the comedian Iliza Shlesinger guessed, wrongly.

As it turns out, she was not alone. It has been one year since the National Suicide Prevention Lifeline underwent a transformation, recasting its 10-digit number as 988, yet many people are unaware of the change or what the hotline provides.

The new number is supposed to make it easier for callers to connect with help when they’re having suicidal thoughts, experiencing emotional distress or having a substance-use-related crisis, but only 17 percent of Americans say they are very or somewhat familiar with it, according to a survey released on Thursday by the National Alliance on Mental Illness. In addition, the survey found, people are still confused about what to expect when they call.

Many still assume that “you call 988 and — much like 911 — that means someone is going to be dispatched to you,” said Hannah Wesolowski, NAMI’s chief advocacy officer. “For the vast majority — almost all callers — that’s not actually the case.”

Here’s a look at what everyone should know about 988 and the challenges that lie ahead in continuing to fund and expand the network.

What should you know about 988?

The three-digit dialing code for the 988 Suicide and Crisis Lifeline became available in July of last year after receiving bipartisan support. (President Donald J. Trump signed the law establishing the new number in 2020.) Since then, more than five million calls, chats and texts have been routed to 988, a 66 percent increase from the previous 12 months, before the arrival of the new number.

Almost one million of those contacts were answered by Veterans Crisis Line, which is linked to 988.

According to the survey, most people either assume that calling 988 will automatically dispatch emergency services such as the police, or aren’t sure, but in reality, less than 2 percent of Lifeline calls require a connection to services like 911. In fact, 988 does not currently use geolocation, so those who call the hotline remain anonymous unless they choose to disclose identifying information. Part of the impetus behind creating 988 was to reduce the reliance on law enforcement or emergency departments to handle mental health crises, and instead to build an expanded group of services, the Substance Abuse and Mental Health Services Administration has said. In some areas, that includes mobile crisis teams and stabilization centers, which offer people a place to go that isn’t an emergency room.

But you don’t need to be in crisis or suicidal to call 988 and speak with a counselor. It is a free service available at all hours, day or night, for anyone who needs support.

“It’s our hope that people will come to us before they are in a mental health crisis,” said Tia Dole, chief officer of the 988 Suicide and Crisis Lifeline at Vibrant Emotional Health, the New York-based nonprofit that manages the Lifeline for SAMHSA.

Why do so few people know about it?

The NAMI survey found that most Americans did not know crucial facts about the Lifeline or what to expect if they call.

This is partly by design. Over the last year, none of the Lifeline’s nearly $1 billion in federal funding was allocated toward a public relations campaign. Initially, advocates and administrators alike worried that promoting 988 too early might cause it to become overwhelmed by demand.

But the time has come to raise broader awareness, Dr. Dole said. Vibrant is aiming to start a campaign in the fall that will not only get the word out but also attempt to decrease some of the disparities among those who understand and embrace 988.

According to NAMI, for example, Black people and adults 50 and older were the least likely to have heard of 988. A Pew study released in April found similar results, and uncovered disparities along economic lines as well: People who were more affluent or had higher levels of education were also more likely to be aware of 988.

What other hurdles remain?

Aside from increasing public awareness, one of the biggest problems facing the expanded network is long-term funding.

The national network has more than 200 call centers, mostly composed of nonprofits with small budgets. Many rely on volunteers and private contributions.

The law that established 988 gave state lawmakers the option of raising money for call centers by adding a monthly fee on phone bills. But so far only a handful of states have done so.

The Biden administration’s 2024 budget proposal includes $836 million for 988, an increase of more than $300 million from the amount allocated last year to get the Lifeline up and running. But experts say more is needed, particularly at the local and state levels.

In the coming year, the number of calls, texts and chats that come to 988 could be as high as nine million, almost double the number of contacts in the first year, said Bob Gebbia, the chief executive of the American Foundation for Suicide Prevention.

“That’s an enormous increase, and we want to make sure that there’s someone there to answer the calls and texts and chats,” he said. “We need to have additional funding.”

The expansion of the network is further complicated by a shortage in behavioral health professionals. When local centers cannot pick up, calls are pushed to national backup centers, which can result in higher wait times or cause callers to simply hang up.

Finally, the current method of routing callers by area code can be problematic if someone’s phone number doesn’t reflect where they currently live. Crisis counselors who assist people who live in other states may have more difficulty offering local referrals.

What is the Lifeline doing right?

The Lifeline encountered record demand in the last year, but it managed to reduce the wait time for a response from a counselor.

“This means that more people are getting help and they are getting help more quickly, which is crucial for a person in crisis,” Miriam E. Delphin-Rittmon, the leader of SAMHSA, said in a statement on Thursday.

Before 988 was implemented, it might take several minutes to reach someone. Now the average response time has decreased from 2 minutes and 39 seconds to 41 seconds, according to SAMHSA. The wait time can vary substantially, however, depending on the location or time of day.

Another big change: The new Lifeline has invested in answering texts and chats. In the past the Lifeline had the capacity to handle only 56 percent of text messages and 30 percent of chats. So far recent data indicates that the new Lifeline is answering a much higher proportion of chats and texts on average.

Overall, “I am convinced it is helping to save lives,” Mr. Gebbia said of 988.

What’s next?

Demand for the Lifeline is expected to surge in the years ahead as mental illness continues to be a large public health problem. Anxiety and depression are widespread, particularly among young adults: A KFF analysis of census data found that half of adults ages 18 to 24 reported anxiety and depression symptoms in 2023, compared with about a third of adults overall. In addition, the suicide rate has increased by 35 percent over the last two decades.

In addition to serving the population at large, the 988 Lifeline also aspires to provide help tailored to specific groups. The Lifeline now offers an L.G.B.T.Q. “subnetwork” for those under the age of 25 and this month rolled out Spanish text and chat options.

In addition, Dr. Dole said that later this year the Lifeline is planning to add a video phone service for the deaf and hard of hearing.

If you are having thoughts of suicide, call or text 988 to reach the 988 Suicide and Crisis Lifeline or go to SpeakingOfSuicide.com/resources for a list of additional resources. Go here for resources outside the United States.