What is the most addictive drug?

Research suggests that nicotine is often considered one of the most addictive drugs.

Addiction Mechanism: Nicotine rapidly affects the brain, triggering the release of dopamine and other neurotransmitters associated with pleasure and reward. This creates a strong reinforcing effect, making users want to repeat the experience. Over time, the brain adapts to the presence of nicotine, leading to tolerance (needing more to achieve the same effect) and withdrawal symptoms (unpleasant physical and psychological effects when stopping).
Accessibility and Social Acceptability: Nicotine, often consumed through smoking or vaping, is widely available and, despite increasing restrictions, remains socially acceptable in some contexts. This ease of access contributes to its addictive potential.
Withdrawal Symptoms: Nicotine withdrawal can cause a range of symptoms, including intense cravings, irritability, anxiety, difficulty concentrating, restlessness, increased appetite, and sleep disturbances. These symptoms can be very difficult to manage, often leading users to relapse.
Health Consequences: While nicotine itself is not the primary cause of many smoking-related diseases, it is highly addictive and sustains the addiction to tobacco products, which contain thousands of harmful chemicals. These chemicals cause cancer, heart disease, lung disease, and other serious health problems.
Prevalence of Use: The widespread use of nicotine-containing products around the world significantly contributes to its impact as an addictive substance.