One occasion, she claims, was after being subjected to what she called "intimate terrorism" by her millionaire ex-husband Charles Saatchi.
The 53-year-old was testifying at the trial of two of her personal assistants who are facing fraud charges.
They're accused of misusing hundreds of thousands of pounds on a credit card belonging to Saatchi's company.
Sisters Elisabetta and Francesca Grillo, who worked for Lawson for more than a decade, deny the fraud accusations and their lawyers claim there was a "tacit understanding" that they could spend what they liked as long as they didn't tell anyone about Lawson's alleged drug use.
But Lawson maintains she has "never been a drug addict or abuser".
The court heard the assistants spent some of the money on lavish purchases like flights to New York, hotel stays, designer handbags and clothes.
The trial continues.