Patients with schizophrenia who are heavy cigarette smokers are more likely to use substances such as alcohol than are those with the disease who are non–heavy smokers. Heavy smokers also are more likely to have elevated cholesterol, a retrospective analysis of 745 patient records has found.

In light of the health risks associated with heavy smoking and elevated cholesterol, “every effort to decrease cigarette intake or stop smoking should be made for smokers with schizophrenia as part of a multifaceted treatment plan,” wrote Heidi J. Wehring, Pharm.D., of the Maryland Psychiatric Research Center, Baltimore, and her colleagues.

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“Every effort to decrease cigarette intake or stop smoking should be made for smokers with schizophrenia as part of a multifaceted treatment plan,” wrote Heidi J. Wehring, Pharm.D.

The investigators reviewed the records of patients who had been admitted to inpatient mental health facilities in Maryland between 2003 and 2007 with a diagnosis of schizophrenia and a history of cigarette smoking. The number of records that met the criteria totaled 745 (Schizophrenia Res. 2012;138:285-9).

Patients were identified as either heavy smokers, which means they smoked one or more packs of cigarettes per day, or non–heavy smokers, which was defined in the study as less than one pack per day at admission. Records that did not specify the extent to which patients smoked were not included in the data analysis.

Dr. Wehring and her colleagues then looked at the records to determine patients’ use of substances such as alcohol, cocaine, cannabis, heroin, lysergic acid diethylamide (LSD), phencyclidine (PCP), inhalants, and amphetamines. They also looked at other health risks, such as history of diabetes and cardiovascular disease, height and weight used to calculate body mass index, systolic and diastolic blood pressure, blood glucose, cholesterol, and triglyceride levels.

A total of 43% of the smokers were classified as heavy smokers, and 57% were non–heavy smokers. Other factors between the two groups were similar, including average age (40 for heavy smokers and 42 for non–heavy smokers), gender, and race. In addition, no significant differences were found between the two groups in triglyceride levels, glucose, systolic or diastolic blood pressure, or mean BMI.

However, Dr. Wehring found that total cholesterol was significantly higher among heavy smokers (190.7 mg/dL), compared with non–heavy smokers (178.2 mg/dL). In addition, significant differences were found between the two groups in the use of alcohol, (68% vs. 58%, P = .01); cocaine, (35% vs. 25%, P = .01); and other substances of abuse, (34% vs. 23%, P = .003). Significant differences in the use of either cannabis or heroin were not found.

“This may warrant future attention to distinguish if use and abuse patterns may differ between various substances,” Dr. Wehring wrote. “However, the increased use of alcohol and cocaine in the heavy smoking sample is of note for future research and clinical intervention, as use of other substances may also add to the challenge of tobacco cessation interventions for this population.”

When asked about the study results, Dr. Samuel G. Siris said in an interview that the paper is interesting. “One tricky issue is that causality is not addressed – although the casual reader may be at risk of assuming it,” said Dr. Siris, professor of psychiatry at Zucker Hillside Hospital of the North Shore–Long Island Jewish Health System, Glen Oaks, N.Y.

“In other words, it is not established that more severely elevated cholesterol, for example, is the result of ‘heavy’ smoking as opposed to ‘not heavy’ smoking,” Dr. Siris said. “But does this paper inadvertently tease the reader into thinking that cutting down on heavy smoking to non-heavy amounts would automatically benefit their health and/or substance use profile? Association does not necessarily imply causality.”

Despite these concerns, Dr. Siris said the paper has the benefit of drawing from a large database and is a contribution to the literature.

Limitations of the study include its retrospective design and missing data points for some patients. Also, the generalizability of these findings is difficult because the participants were from an inpatient sample.

The study was funded by the National Institute of Mental Health and the Advanced Centers for Intervention and Services. Neither Dr. Wehring nor her colleagues reported having financial disclosures.