CHICAGO (Reuters) - A spike in suicide rates in the United States has cast fresh light on the need for more effective treatments for major depression, with researchers saying it is a tricky development area that has largely been abandoned by big pharmaceutical companies.

FILE PHOTO: Kate Spade arrives at the Council of Fashion Designers of America awards in New York on June 2, 2003, at the New York Public Library. REUTERS/Chip East/File Photo

U.S. health authorities said on Thursday that there had been a sharp rise in suicide rates across the country since the beginning of the century and called for a comprehensive approach to addressing depression. The report was issued the same week as the high-profile suicides of celebrities Anthony Bourdain and Kate Spade.

Reuters was not able to determine if either Bourdain or Spade were getting drug treatment.

Kate Spade’s husband Andy Spade said in a statement this week that she had suffered from depression for many years and was working closely with her doctors. A representative for Andy Spade said he had no further comment on Saturday. A representative for Bourdain could not immediately be reached for comment.

With the availability of numerous cheap generic antidepressants, many of which offer only marginal benefit, developing medicines for depression is a tough sell.

Drugmakers have 140 therapies in development targeting mental health issues, including 39 aimed at depression, according to the Pharmaceutical Research and Manufacturers of America trade group. That compares with the industry’s work on some 1,100 experimental cancer drugs, which can command some of the highest prices.

“Psychiatry has become a disfavored area for investment,” said Harry Tracy, whose newsletter NeuroPerspective tracks developments in drug treatments for psychiatric problems. “Insurers say ‘why should we pay more for a new treatment?’”

Some say anti-depressant drugs take too long to become effective, if they are effective at all.

About half of people with depression fail to respond to current therapies, said Dr. Husseini Manji, global head of neuroscience at Johnson & Johnson JNJ.N's Janssen unit.

Developing antidepressants is risky. Patients in clinical trials often show a big placebo response, masking the efficacy of the drug being tested. In addition, once approved, antidepressants require a large sales force to reach psychiatrists as well as primary care providers.

Another impediment is the difficulty of conducting early depression research on animals that could form a basis for trials in people.

“This has been a big challenge to translate over to human clinical trials,” said Caroline Ko, project leader of NewCures, a newly formed program at Northwestern University aimed at reducing the risk of investment in treatments for depression, pain, Parkinson’s and other diseases.

J&J is the only large pharmaceutical company making a major investment in a new antidepressant, Tracy said. Smaller players include Sage Therapeutics SAGE.O, which expects a decision from U.S. regulators on a treatment for post-partum depression by the end of the year.

J&J’s esketamine targets treatment-resistant depression. It is similar to ketamine, which is used as an anesthetic and to relieve pain, and often abused as a recreational party drug with the street nickname Special K.

The company expects to file for U.S. Food and Drug Administration approval of esketamine, a rapid-acting nasal spray, this year.

“Standard antidepressants can take weeks to work. They really are not useful in a crisis situation,” said Carla Canuso, who is leading J&J’s effort testing the drug in people deemed at imminent risk for suicide, which is most commonly associated with depression.

Allergan Plc AGN.N is developing rapastinel, a fast-acting intravenous antidepressant the company purchased in 2015.

The drug has breakthrough therapy designation from the FDA, with clinical trial results expected in early 2019. Last month, the company acquired another depression drug from its collaborator Aptinyx.

Dr. Julie Goldstein Grumet, a behavioral health expert from the Suicide Prevention Resource Center, said 122 people in the United States took their lives by suicide each day last week. Many were never even diagnosed with a mental illness.

“We’re missing opportunities to screen people for the risk of suicide,” she said.