But that’s what you said. Nicotine is the addictive part

The short version: the retrieved evidence still does not isolate nicotine from whole smoke, so the question of whether nicotine alone is the addictive component remains unanswered by these studies.

The studies here measure nicotine dependence through questionnaires in people smoking whole cigarettes [1][2], and they confirm that nicotine acts on brain reward circuits [3][4]. But that is not the same as proving nicotine alone drives addiction. Cigarette smoke contains thousands of chemicals, including acetaldehyde and monoamine oxidase inhibitors that may reinforce smoking behavior independently of nicotine. None of the retrieved studies compared nicotine-only exposure to whole cigarette smoke in humans.

One study does show that nicotine alone can produce withdrawal symptoms in rats [3], and another documents that nicotine activates opioid pathways in the brain [2]. These animal models suggest nicotine has addictive potential on its own. But the dose, delivery speed, and context differ sharply from smoking. Human nicotine replacement studies (outside this retrieval) show that pure nicotine maintains self-administration but at much lower rates than cigarettes, which points to other smoke constituents playing a significant role.

The evidence here cannot separate nicotine's contribution from the rest of the smoke. The question would need a study comparing addiction rates in people using pure nicotine products versus whole cigarettes, with matched dosing. That study is not in this retrieval.

My call: the retrieved evidence does not show that nicotine alone is the addictive component of cigarettes. Confidence: not clear from this retrieval.