Effects of rTMS on Cigarette Smoking and Cognition in Schizophrenia

Effects of Repetitive Transcranial Magnetic Stimulation on Cigarette Smoking and Cognitive Function in Smokers With and Without Schizophrenia

Cigarette smoking rates are extremely high in persons with schizophrenia and this increases the risk of disease and death due to tobacco-related disorders. One of the features of schizophrenia is reduced cognitive abilities, such as poor attention and memory. It is thought that people with schizophrenia smoke cigarettes to reduce these cognitive problems, as nicotine can improve cognitive function in these people. When people with schizophrenia stop smoking it causes further cognitive difficulties, which makes quitting harder for them compared to people without schizophrenia. A method called repetitive transcranial magnetic stimulation (rTMS) allows clinicians to give repeated magnetic pulses through the scalp to cause changes in brain activity and behaviour. rTMS can improve cognitive function in people with schizophrenia. Studies have also shown that rTMS can reduce tobacco craving and consumption of cigarettes. Therefore, we believe that rTMS will improve the cognitive deficits observed during cigarette smoking abstinence and help reduce cravings for cigarettes. Ultimately, rTMS may help smokers with schizophrenia who can't quit smoking with available treatments. This study will examine the effect of rTMS on tobacco cravings and cognitive problems produced by overnight abstinence from cigarette smoking in persons with schizophrenia in comparison to people without mental illness who smoke. Important information about the potential of rTMS for the treatment of cognitive deficits and tobacco addiction in schizophrenia will be obtained. Providing more effective smoking cessation treatments in people with schizophrenia may lead to improved physical and mental health for these patients, who are extremely susceptible to tobacco addiction and tobacco-related illness.

Inclusion Criteria for all subjects:

1. Have a Full Scale IQ ≥ 80 as determined by the Shipley-2 which provides an estimate of pre-morbid intelligence
2. Be non-treatment seeking smokers;
3. Have a score greater than 5 on the Fagerstrom Test of Nicotine Dependence (FTND), a 5-item multiple choice questionnaire which assesses nicotine dependence
4. Report smoking of at least 10 cigarettes per day using a self-report 7-day timeline follow-back
5. Have an expired breath CO level >10ppm
6. Be able to provide informed consent.

Inclusion Criteria for Schizophrenia Subjects:

1. Meet SCID for DSM-IV diagnostic criteria for schizophrenia or schizoaffective disorder
2. Be in stable remission from positive symptoms of psychosis as judged by psychiatric evaluation and a PANSS total score <70
3. Be receiving a stable dose of antipsychotic mediation(s) for at least one month.

Inclusion Criteria for Healthy Controls:

1. Do not meet SCID for DSM-IV criteria for any current or past psychiatric disorder except for past major depression if it has been in remission for a minimum of one year
2. Not taking any psychotropic medications

General Exclusion Criteria:

1. Meet criteria for abuse or dependence of alcohol or illicit substances within the past 3 months (with the exception of nicotine dependence or caffeine)
2. Use of nicotine replacement or tobacco products other than cigarettes
3. Concomitant medical illness (including unstable or other presentations thought by investigators to compromise study participation, e.g. diabetes mellitus, hypothyroidism or acute/chronic renal insufficiency) or neurological illness including a history of seizures or a first-degree relative with a history of a seizure disorder
4. Be pregnant or planning to become pregnant
5. Metallic implants.