Britney Spears will blame a recent positive drug test on her medication for Attention Deficit Disorder when her lawyer appears at an emergency hearing on Friday (16Nov07) relating to her custody battle with KEVIN FEDERLINE. Federline's lawyer Mark Vincent Kaplan called for the meeting earlier this week (begs12Nov07), claiming the dancer was becoming increasingly concerned over the safety of the couple's sons Sean Preston and Jayden James while in Spears' care. And Kaplan will also demand an explanation for media reports the Toxic hitmaker tested positive for amphetamines in a recent court-ordered drug test. The 25-year-old must undergo mandatory drug and alcohol tests as part of an earlier court order relating to her custody case. But TMZ.com claims Spears' attorney, Sorrell Trope, will now argue the positive test was caused by the amphetamine Adderall - a drug she has been prescribed to treat the illness. According to further media reports, Spears has previously claimed her sleeping aid Provigil was the drug responsible for the positive result, before changing her argument to lay blame on her asthma inhaler, Albuterol. Kaplan is also expected to call for a driving ban on the singer while the kids are in her custody, after video footage emerged last week (ends09Nov07) showing Spears running through a red traffic light at a busy Los Angeles junction.