Final answer:
The addictive drug in tobacco is nicotine, a stimulant that causes addiction through interactions with brain receptors and is present in various tobacco products and cessation aids. Tobacco smoke contains numerous carcinogens like benzopyrene, increasing cancer risks.
Step-by-step explanation:
The addictive drug in tobacco is nicotine. Nicotine is the active chemical constituent in tobacco that causes addiction and dependence. It is present in a variety of tobacco products such as cigarettes, cigars, and chewing tobacco, as well as smoking cessation aids like nicotine patches and gum. Nicotine acts as a stimulant and exerts its effects through the agonism of nicotinic acetylcholine receptors, ultimately increasing activity in the brain's reward system and leading to addiction. Not only is nicotine addictive, but the use of tobacco products also increases the risks of heart disease, stroke, and a variety of cancers.
Among the multiple toxic chemicals found in tobacco smoke, benzopyrene, acrolein, and nitrosamines are some of the most potent carcinogens. The exposure to these substances can lead to DNA mutations and increase the risk of developing cancer. It is important to note that while nicotine replacement therapies are available for those trying to quit smoking, the success rates can be low, and it is critical for individuals to seek additional support and interventions for more effective outcomes.