Cigarette smoking and other forms of tobacco addiction are very common among patients with mental disorders. For instance, in the United States, 25 to 30 percent of people smoke, but 75 to 90 percent of those with schizophrenia smoke, according to the National Institute of Mental Health (NIMH). Other mental disorders that are highly associated with smoking include:

• Mood disorders, such as depression, dysthymia and bipolar disorder
  
  
• Anxiety disorders, such as generalized anxiety disorder (GAD)
  
  
• Attention-deficit hyperactivity disorder (ADHD)
  

Smoking is also very common among patients who abuse or are dependent on other substances including alcohol, indicating that their may be an association between them.

Nicotine is known to promote the release of certain neurotransmitters, such as dopamine, serotonin and norepinephrine. These neurotransmitters are related to mental health and their levels are associated with a number of mental health problems. Some of these conditions, particularly mood disorders, may develop in patients at risk for the disorder when they stop smoking.

Nicotine has many affects on both the mind and the body, several of which may seem beneficial in the short run. For example, nicotine may reduce anxiety, boost a person’s energy level and help improve concentration and sensory perception (e.g., hearing) in some people.

The use of nicotine can affect the metabolism of certain medications.   This reduces their effectiveness and may require patients to take higher doses of a drug.

Research on the relationship between smoking and mental disorders continues. However, the medical consequences of smoking have been well documented. Smoking is the most preventable cause of death in the United States. Smokers have a greatly increased risk of many cancers (e.g., lung, oral, throat, bladder, kidney cancers), heart and lung diseases and peptic ulcer disease.