arijuana. In fact, some people experience a worsening of their schizophrenic symptoms when they are taking such drugs. Substance abuse also reduces the likelihood that patients will follow the treatment plans recommended by their doctors.Schizophrenia and NicotineThe most common form of substance use disorder in people with schizophrenia is nicotine dependence due to smoking. While the prevalence of smoking in the U.S. population is about 25 to 30 percent, the prevalence among people with schizophrenia is approximately three times as high. Research has shown that the relationship between smoking and schizophrenia is complex. Although people with schizophrenia may smoke to self medicate their symptoms, smoking has been found to interfere with the response to antipsychotic drugs. Several studies have found that schizophrenia patients who smoke need higher doses of antipsychotic medication. Quitting smoking may be especially difficult for people with schizophrenia, because the symptoms of nicotine withdrawal may cause a temporary worsening of schizophrenia symptoms. However, smoking cessation strategies that include nicotine replacement methods may be effective. Doctors should carefully monitor medication dosage and response when patients with schizophrenia either start or stop smoking.Disordered ThinkingSchizophrenia often affects a person's ability to "think straight." Thoughts may come and go rapidly; the person may not be able to concentrate on one thought for very long and may be easily distracted, unable to focus attention.People with schizophrenia may not be able to sort out what is relevant and what is not relevant to a situation. The person may be unable to connect thoughts into logical sequences, with thoughts becoming disorganized and fragmented. This lack of logical continuity of thought, termed "thought disorder," can make conversation very difficult and may contribute to social isolation. If people cannot make sense of what a...