Nicotine has a reputation for relieving anxiety. Nicotine dependence is more common among people with ADHD, anxiety disorders, and depression. Research suggests nicotine may play a role in relieving symptoms of these mental illnesses.  At the same time, nicotine withdrawal can cause anxiety, depression, and difficulty concentrating. The science isn’t clear on why people with mental health issues are more likely to use tobacco. It could be because it relieves symptoms or because withdrawal symptoms compound the underlying issues, making it harder to quit.