^ Klein C, Karanges E, Spiro A, Wong A, Spencer J, Huynh T, Gunasekaran N, Karl T, Long LE, Huang XF, Liu K, Arnold JC, McGregor IS (November 2011). "Cannabidiol potentiates Δ⁹-tetrahydrocannabinol (THC) behavioural effects and alters THC pharmacokinetics during acute and chronic treatment in adolescent rats". Psychopharmacology. 218 (2): 443–457. doi:10.1007/s00213-011-2342-0. PMID 21667074.
The symptoms of nicotine overdose are clearer indicators of what is happening in your body than the symptoms of withdrawal. This is because nicotine overdose has been studied a fair bit. Nicotine withdrawal has not been studied nearly as much. What has been studied a lot is cigarette withdrawal which is a different thing – it includes no longer inhaling a few thousand chemicals, not just nicotine.