Emma Roberts' recent domestic violence arrest came as a SHOCK to the public ... but not to some of her friends ... who fear the actress is headed down a deep, dark path a la Lindsay Lohan.

Sources close to Emma tell TMZ ... over the last year Emma has dug herself deep into the L.A. party scene. We're told it all started after she broke up with "Glee" star Chord Overstreet -- she began going out all night, hitting the clubs and surrounding herself with people who don't keep their noses clean.

Our sources say a lot of Emma's friends don't know how to help her because Emma won't acknowledge the change in her behavior.

Indeed, we're told after her arrest ... Emma wouldn't talk to her friends about it, acting like nothing happened. Her friends are convinced ... a night of partying contributed to the brawl and the arrest.

TMZ broke the story ... Emma was arrested​ in Canada earlier this month, after she allegedly gave her boyfriend a bloody nose during a blow-out fight. Sources connected with Emma say it was mutual combat. The matter was dropped after her BF chose not to press charges.