Nicotine increases the release of norepinephrine and epinephrine, leading in a rise in heart rate and blood pressure phenomenologically. Nicotine, at high quantities, can cause physiological consequences similar to panic attacks. This is known as nicotine toxicity. The symptoms include dizziness, headache, rapid heartbeat, shortness of breath, and chest tightness. People who smoke or use tobacco products often report experiencing anxiety-related feelings such as fear, panic, apprehension, anger, frustration, embarrassment, guilt, loneliness, disappointment, shame, and remorse. These individuals are also likely to report feeling depressed. It is possible that the chronic exposure to nicotine causes changes in the brain that lead to these effects. It is well documented that people who suffer from panic disorder are more likely to be smokers. Studies have shown that if you ask patients with panic disorder about cigarettes, they will tell you that they love them. However, if you probe further and ask how many cigarettes they are smoking daily or weekly, the number usually comes down to less than ten. People who experience anxiety tend to think that nothing will help them feel better except for something that produces the same effect on their body as the thing that makes them feel bad. For example, someone who is anxious about having a panic attack might try smoking marijuana to make themselves feel better.