Reuters reports on studies that link smoking to psychosis, which includes schizophrenia. 

Psychosis is a mental disorder where the patient hears voices, has delusions and gets paranoid.  It is an abnormal condition, where the patient seems to have his own world, detached from reality.  A person with this disorder may act abnormally, and does not interact well with others.  Psychosis, being a broad field, includes schizophrenia.  A person suffering from this is detached from reality, with incidents of confusions and hallucinations.

Dr James Macabe is one of the authors of this study.  He is a member of the King's Institute of Psychiatry, Psychology and Neuroscience. 

One of the links as the study shows is that 57% of the people that enter mental institutions for the first time are smokers.  While non-smokers also may be affected by psychosis, smokers experience it earlier.

The research was made on 15,000 smokers and 273,000 smokers, and although the link between smoking and schizophrenia can be established, still other factors play a role.  These are genetics, diet, lifestyle and other influences. 

The key ingredient of tobacco is nicotine, which causes excess in dopamine.  This functions as a neuro-transmitter that sends signals from one nerve cell to another. "Dopamine plays a role in learning from undesirable outcomes and information".  The bottom-line is that tobacco is known to cause psychosis and schizophrenia.  Marijuana, which is from Cannabis plant, also causes these. 

People who experience stress believe they relieve themselves when they smoke.  But if this study is to be used as basis, the opposite may be true.  You smoke, and then you experience stress.

Further genetic investigation will reveal absolute links between smoking and psychosis.  As of this research, smoking is just one of the factors. 

The next time you light up, look behind you.  There might be someone stalking you.  But then again, that may just be your psychotic self you're seeing.