A functional polymorphism in the interleukin-1beta and severity of nicotine dependence in male schizophrenia: a case-control study

Nicotine dependence in Croatian male inpatients with schizophrenia

BACKGROUND

Patients with schizophrenia have the highest known rates of cigarette smoking, but less is known about their smoking behavior and the differences across geographical regions, including Croatia. The aim of this study was to compare patterns of nicotine dependence between patients with schizophrenia and healthy individuals, and to determine the relationship between clinical presentation and the severity of smoking.

METHODS

This cross-sectional study included 182 recently hospitalized male inpatients and 280 healthy males, who were daily smokers. All participants have fulfilled the Fagerstrom Test for Nicotine Dependence (FTND). Patients were also evaluated by the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Patients had higher FTND total score (p = 0.010), smoked their first cigarette earlier in the morning (p = 0.000), consumed higher number of cigarettes (p = 0.000), while healthy subjects had more difficulties to refrain from smoking in places where it is forbidden (p = 0.000) and smoked more even when they were sick (p = 0.000). While severe dependence was more prevalent in the patient group, light dependence was more frequent in control subjects (p = 0.04). Smoking behavior was not associated with either PANSS total score or any of its subscales and items.

CONCLUSIONS

Smokers with schizophrenia differ from healthy smokers in both smoking behavior and level of dependence. Longitudinal studies are needed to shed more light on the complex relationship between smoking and psychopathology in schizophrenia.

Nicotine dependence is associated with depression and childhood trauma in smokers with schizophrenia: results from the FACE-SZ dataset

In a perspective of personalized care for smoking cessation, a better clinical characterization of smokers with schizophrenia (SZ) is needed. The objective of this study was to determine the clinical characteristics of SZ smokers with severe nicotine (NIC) dependence. 240 stabilized community-dwelling SZ smokers (mean age = 31.9 years, 80.4% male gender) were consecutively included in the network of the FondaMental Expert Centers for Schizophrenia and assessed with validated scales. Severe NIC dependence was defined by a Fagerstrom questionnaire score ≥ 7. Depression was defined by a Calgary score ≥ 6. Childhood trauma was self-reported by the Childhood Trauma Questionnaire score (CTQ). Ongoing psychotropic treatment was recorded. Severe NIC dependence was identified in 83 subjects (34.6%), depression in 60 (26.3%). 44 (22.3%) subjects were treated by antidepressants. In a multivariate model, severe NIC dependence remained associated with depression (OR = 3.2, p = 0.006), male gender (OR = 4.5, p = 0.009) and more slightly with childhood trauma (OR = 1.03, p = 0.044), independently of socio-demographic characteristics, psychotic symptoms severity, psychotropic treatments and alcohol disorder. NIC dependence was independently and strongly associated with, respectively, depression and male gender in schizophrenia, and only slightly with history of childhood trauma. Based on these results, the care of both nicotine dependence and depression should be evaluated for an effective smoking cessation intervention in schizophrenia.

An association between the PPARα-L162V polymorphism and nicotine dependency among patients with schizophrenia

OBJECTIVE

Patients with schizophrenia are more likely to be smokers than the general population, which makes them an interesting group with which to study the etiology of nicotine dependency. We studied the prevalence of a gene variant of peroxisome proliferator-activated receptor alpha (PPARα) in schizophrenia, together with nicotine dependency, to investigate whether the PPARα-L162V polymorphism (rs1800206) influences nicotine dependency in schizophrenia. Given evidence suggesting that smoking influences the severity of schizophrenia, together with our recent data linking the PPARα-L162V polymorphism to clinical manifestations of schizophrenia (in the Croatian population), we hypothesized that interactions between the two (smoking and the PPARα-L162V polymorphism) might contribute to disease onset and scores for the Positive and Negative Syndrome Scale. To the best of our knowledge, this is the first study to investigate the possible associations between the PPARα gene and nicotine dependency.

PATIENTS AND METHODS

Genotyping was performed for 267 chronically ill schizophrenia patients (males/females: 140/127) by polymerase chain reaction.

RESULTS

A significant excess of PPARα-L162V genotypes and PPARα-162V alleles were detected among female smokers in comparison to female nonsmokers (18.2% vs. 2.0%, and 9.1% vs. 1.0%, p<0.01, respectively). We also revealed a significant PPARα genotype-smoking interaction that predicted positive symptom severity among male patients (F=4.43, p<0.05). These data indicated that the PPARα-L162V heterozygous genotype, depending on smoking status, might be of relevance as either protective, or a risk factor, for the severity of positive symptoms. No interaction between the PPARα-L162V polymorphism and smoking for the time of onset of schizophrenia was detected (p>0.05, respectively).

CONCLUSION

We demonstrated two significant yet weak effects. The first showed an effect of the PPARα-L162V polymorphism on the risk of nicotine dependency. The second linked the PPARα genotype-smoking interaction to positive symptoms severity among schizophrenia patients; both effects manifested in a gender-specific fashion.