(a) Except as otherwise provided in this Section, a claim under this Act shall not be brought more than 2 years after the cause of action accrues. A cause of action accrues under this Act when a person who may recover has reason to know of the harm from illegal drug use that is the basis for the cause of action and has reason to know that the illegal drug use is the cause of the harm.
     (b) For a plaintiff, the statute of limitations under this Section is tolled while the individual potential plaintiff is incapacitated by the use of an illegal drug to the extent that the individual cannot reasonably be expected to seek recovery under this Act or as otherwise provided by law. For a defendant, the statute of limitations under this Section is tolled until 6 months after the individual potential defendant is convicted of a criminal drug offense or as otherwise provided by law.