Publications (18) View all
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Article: Testing the psychosis continuum: differential impact of genetic and nongenetic risk factors and comorbid psychopathology across the entire spectrum of psychosis.
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ABSTRACT: A growing number of studies demonstrate high rates of subthreshold psychotic experiences, but there is considerable heterogeneity in rates due to study cohort and design factors, obscuring how prevalent psychotic experiences may or may not relate to rare psychotic disorders. In a representative general population sample (n = 4011) in Izmir, Turkey, the full spectrum of expression of psychosis was categorized across 5 groups representing (1) absence of psychosis, (2) subclinical psychotic experiences, (3) low-impact psychotic symptoms, (4) high-impact psychotic symptoms, and (5) full-blown clinical psychotic disorder and analyzed for continuity and discontinuity in relation to (1) other symptom dimensions associated with psychotic disorder and (2) proxies of genetic and nongenetic etiology. Results were tested for linear and extralinear contrasts between clinical and nonclinical and between disorder and nondisorder expression of psychosis. Demographic variables, indexing premorbid social adjustment and socioeconomic status, impacted mostly linearly; proxy variables of genetic loading (more or more severely affected relatives) impacted in a positive extralinear fashion; environmental risk factors sometimes impacted linearly (urbanicity and childhood adversity) and sometimes extralinearly (cannabis), occasioning a disproportional shift in risk at the clinical disorder end of the spectrum. Affective symptoms were associated with a disproportionally higher risk below the disorder threshold, whereas a disproportionally higher risk above the threshold was associated with psychotic symptom load, negative symptoms, disorganization, and visible signs of mental illness. Liability associated with respectively affective and nonaffective symptom domains, in interaction with environmental risks, may operate by impacting differentially over a quasi-continuous extended psychosis phenotype in the population.Schizophrenia Bulletin 04/2011; 38(5):992-1002. · 8.80 Impact Factor -
Article: Izmir mental health survey for gene-environment interaction in psychoses (TürkSch): objectives and methodology.
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ABSTRACT: To describe the objectives and design of a multistage study on the prevalence and risk factors of mental health problems, in particular psychotic disorders and psychotic symptoms, by assessing a probabilistic sample of household residents in the Izmir Metropolitan Area, aged 15-64 years. The study included three different observation frames. In the first stage, of which methodology is in the focus of this paper, the primary screening instrument was the Composite International Diagnostic Interview 2.1, which assesses lifetime and/or last one year occurrence of several DSM-IV disorders. Second, a parallel survey of social capital of administrative wards was conducted in the same neighbourhoods. Third, a nested-case control study was performed to study effects of genetic and environmental risk factors on wide psychosis phenotype. A total of 4011 males and females were contacted through a multistage clustered area probability sample of administrative neighbourhoods and households, covering 9 districts and 302 neighbourhoods. The response rate for the first stage was 76.5% in 5242 eligible households. Respondents were interviewed at home in 2008 for the screening of included mental health problems. The screened disorders were mood disorders (last 1 year), schizophrenia and other non-affective psychotic disorders (lifetime), and dependence and abuse of psychoactive substances (lifetime). Although cross-sectional in nature, the TürkSch has a unique study design and yields data of high quality. This enables study of the prevalence, risk and higher-order interactions underlying ill-health in the Turkish population, with a specific focus on psychosis.Turk psikiyatri dergisi = Turkish journal of psychiatry 01/2011; 22(2):65-76. · 0.43 Impact Factor -
Article: [The psychosis epidemiology in Turkey: a systematic review on prevalence estimates and admission rates].
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ABSTRACT: To provide prevalence estimate, admission rates and related features of psychotic disorders in Turkey. Studies with data on prevalence and/or rates in outpatient or inpatient admissions after 1990 were included. Strings of ([schizo*OR psych*] AND Turkey) were used in PubMed and PsychINFO to detect relevant studies. Turkish Medical and Psychiatry indexes were screened with Turkish keywords. Abstract books of national congresses, national index of thesis, and references of the included papers were searched for additional data. Results were presented as prevalence per 1000 and median values of admission rates. A total of 56 studies were included, including 8 cross-sectional (4 core and 4 special group), 27 outpatient and 21 inpatient admission estimates or rates. The lifetime prevalence of schizophrenia in general population (pooled data, n: 6022) was 8.9 per 1000 (Standard error [SE]: 1.2; 95% confidence interval [CI]: 6.6-11.3). Psychosis prevalence is higher in subgroups including university students, prisoners and homeless people. Patients with a diagnosis of psychotic disorder constituted 7.6% and 26.9% of adult outpatient and inpatient psychiatry admissions. However, median rates vary depending on institutional, regional, temporal and residential features. Male gender was at higher risk in all kinds of estimates and rates for all age groups. Prevalence of schizophrenia in Turkey is higher than the formerly reported estimates in different countries. Higher prevalence may be a consequence of sample properties, environmental risk exposures, and study design. However more research is needed to further elaborate the relatively higher prevalence. Nevertheless, a major part of the psychiatry services are devoted to psychotic outpatients and inpatients.Turk psikiyatri dergisi = Turkish journal of psychiatry 01/2011; 22(1):40-52. · 0.43 Impact Factor -
Article: Body image and self-esteem in somatizing patients.
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ABSTRACT: The aim of the present study was to determine dissatisfaction with body appearance and bodily functions and to assess self-esteem in somatizing patients. Body image and self-esteem were investigated in 128 women; 34 of those had diagnosed somatoform disorders, 50 were breast cancer patients with total mastectomy surgery alone, and 44 were healthy subjects. Body image and self-esteem were assessed using the Body Cathexis Scale and Rosenberg Self-Esteem Scale. The two clinical groups did not differ from one another (z = -1.832, P = 0.067), but differed from healthy controls in terms of body image (somatizing patients vs healthy controls, z = -3.628, P < 0.001; total mastectomy patients vs healthy controls, z = -3.172, P = 0.002). They also did not differ significantly in terms of self-esteem (z = -0.936, P = 0.349) when depressive symptoms were controlled. No statistically significant difference was observed between total mastectomy patients and healthy controls in terms of self-esteem (z = -1.727, P = 0.084). The lower levels of self-esteem in somatizing patients were largely mediated by depressive symptoms. Depressed and non-depressed somatizing patients differed significantly from healthy controls with respect to their self-esteem and body image. Somatizing patients who were dissatisfied with their bodily functions and appearance had lower levels of self-esteem and high comorbidity of depression. In clinical practice it is suggested that clinicians should take into account psychiatric comorbidity, self-esteem, and body image in somatizing patients when planning treatment approaches.Psychiatry and Clinical Neurosciences 07/2009; 63(4):508-15. · 2.13 Impact Factor -
Article: The role of BDNF and HPA axis in the neurobiology of burnout syndrome.
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ABSTRACT: Chronic stress is known to affect the HPA axis. The few clinical studies which have been conducted on HPA-axis function in burnout have produced inconsistent results. The etiological relationship between sBDNF and burnout has not yet been studied. The aim of the current study was to investigate the role of BDNF and HPA axis in the neurobiology of burnout. In the current study 37 clinically diagnosed burnout participants were compared with 35 healthy controls in terms of BDNF, HPA axis, burnout symptoms, depression, anxiety and psychosomatic complaints. Basal serum cortisol, sBDNF and cortisol level after 1 mg DST was sampled. We found no significant differences in terms of HPA-axis function (for basal serum cortisol, p=0.592; for cortisol level after 1 mg DST, p=0.921), but we did find lowered sBDNF levels in burnout group (88.66+/-18.15 pg/ml) as compared to healthy controls (102.18+/-20.92 pg/ml) and the difference was statistically significant (p=0.005). Logistic Regression Analysis revealed that emotional exhaustion (p=0.05), depersonalization (p=0.005) and depression (p=0.025) were significantly associated with burnout. sBDNF levels correlated negatively with emotional exhaustion (r=-,268, p=0.026), depersonalization (r=-,333, p=0.005) and correlated positively with competence (r=0.293, p=0.015) sub-scales of burnout inventory. However, there were no significant relationships between cortisol levels and sBDNF levels (r=0.80, p=0.51), depression, anxiety, psychosomatic complaints and burnout inventory. Our results suggest that low BDNF might contribute to the neurobiology of burnout syndrome and it seems to be associated with burnout symptoms including altered mood and cognitive functions.Progress in Neuro-Psychopharmacology and Biological Psychiatry 06/2008; 32(6):1459-65. · 3.25 Impact Factor
