Amanda Bynes' bizarre antics are being fueled by marijuana, Breaking Celebrity News has exclusively learned.

The ex-Nickelodeon star "has used marijuana as a recreational user for several years," a source close to the troubled actress revealed.

"Amanda's increasingly disturbing behavior is related to the fact that she smokes pot.

"It makes her more paranoid and instead of mellowing her out, it does the opposite. Amanda begins talking faster and just can't seem to sit still."

The 27-year-old's use of drugs has long been serialized: When driving on a suspended licence in Sept. last year, Bynes was photographed p