The federal government is studying how to use Twitter for surveillance on depressed people.

The University of California, San Diego (UCSD) began a study financed by the National Institutes of Health last month that will provide "population level depression monitoring" through the social media site.

The project, "Utilizing Social Media as a Resource for Mental Health Surveillance," is costing taxpayers $82,800.

While Twitter has been used by government agencies, such as the Secret Service and Department of Homeland Security, for national security related monitoring, the project suggests the social network can be used for public health surveillance as well.

"Major depressive disorder is one of the most common debilitating illnesses in the United States, with a lifetime prevalence of 16.2 [percent]," the project grant states. "Currently, nationwide mental health surveillance takes the form of large-scale telephone- based surveys."

The project argues that Twitter is preferable to phone surveys on the mentally ill because the site offers a "multilingual source of real time data for public health surveillance."

"We propose using twitter and [Natural Language Processing] NLP as a cost-effective and flexible approach to augmenting current telephone- based surveillance methods for population level depression monitoring," the grant said.

The researchers will create algorithms to determine if people are depressed through their tweets, which they hope will serve as a basis for monitoring mental illness. They will also engage with depressed individuals on Twitter directly.

"Developing these algorithms and resources will provide the bedrock for building social media based surveillance systems," the grant said.

The study will also look into ethical and privacy issues for using Twitter to survey the mentally ill.

Mike Conway, Project Scientist in the Division of Behavioral Medicine at UCSD, is leading the study. His research interests include "using social media to track health behaviours [sic]."

Conway’s most recent research subject was monitoring tweets about tobacco use.

The project’s "public health relevance statement" states that monitoring Twitter for depressed tweets has "public health at its core." The researchers say the project is innovative because "microblogs have not been used before for mental health surveillance."

The project differs from a 2011 study, which suggested Twitter itself is making its users unhappy.