Don't blame it on the alcohol.

Given Lindsay Lohan's past substance abuse issues -- the 26-year-old star has been to rehab five times -- many may have assumed that her Nov. 29 arrest was fueled by booze or drugs. But her lawyer says the Liz & Dick actress was "perfectly appropriate" and clear-headed when police charged her with assault following a fight at NYC hotspot Avenue.

"I can tell you when I was with her this morning, she was in great condition," attorney Mark Heller told E! News of his client. "She was certainly not intoxicated, certainly not under the influence of drugs. She was clear [and] lucid, her eyes were clear. No alcohol involvement whatsoever on this occasion."

Lohan was taken into custody early Thursday morning after she reportedly yelled at and punched a fellow clubgoer. She's set to face formal third-degree assault charges at an arraignment on Jan. 7, but Heller told E! that he's hoping her case won't even get that far.

"We are going to be working very earnestly to establish that no charges should even be lodged," he said. "[The police] have already made arrangements to get the video from the...club, which hopefully will reveal some exonerating information. After that, they could just walk away from the case and decline to even prosecute."

Even so, Heller has his hands full with Lohan, who was also charged Thursday with obstructing an officer, providing false information, and reckless driving -- all related to her June car accident in Santa Monica, Calif. But he's not the only one on her side.

"Our family's bond grows deeper and stronger during the tough times, and I am beyond proud of all of my children for the love and devotion they provide for each other," the star's mom, Dina, told Radar Online. "We are there for and stand by one another unconditionally."

This article originally appeared on Usmagazine.com: Lindsay Lohan Was Not Drinking, Doing Drugs Before Club Fight, Her Lawyer Says