HOUSTON -

By now, you've probably seen the headlines about troubled individuals posting messages on social networks before ending their lives.

Around Christmas 2010, a British woman wrote on Facebook: "Took all my pills, be dead soon, bye bye everyone." 

Some of her so-called friends mocked her status.  Even those who lived within walking distance did nothing. 

This past summer, days before detectives said she killed her two children and then herself, a Houston woman wrote on Facebook: "Time is winding down...feeling really discouraged." 

Just last month, a Fort Bend County teenager poured her heart out on Twitter about feeling helpless, she said, after years of sexual abuse. No one stepped up to help and she committed suicide.

University of Houston psychologist Dr. Norma Ngo told Local 2 it can be hard to tell the difference between a person in crisis and someone who is just venting.  

"It just takes people to notice those signs of distress and reach out The signs may not mean a person wants to end their life, but it certainly means there's something going on and they would benefit by talking to someone about ," said Dr. Norma Ngo, the director of clinical services for the University of Houston.

That's where social networks can enter the equation and provide an outlet for important dialogue.

Christian Sistrunk, a Marine who served in Iraq, told Local 2 about how he lost a comrade to a roadside bomb and went on Facebook looking for support. 

"I did reach out to my family," Sistrunk said. "At the time the phones were down and the only thing we had was the broadband we had over there. I reached out to friends and people, and they consoled me and made me feel a lot better."

A University of Wisconsin study found those who write on websites like Facebook and Twitter to voice their dark thoughts and sad feelings do feel supported.  Researchers said these sites may act as a mini-support group, especially for those with depression.