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Dive into the research topics where Selim Tümkaya is active.

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Featured researches published by Selim Tümkaya.


Psychiatry Research-neuroimaging | 2009

Schizophrenia with obsessive-compulsive disorder and obsessive-compulsive disorder with poor insight: A neuropsychological comparison

Selim Tümkaya; Filiz Karadag; Nalan Kalkan Oguzhanoglu; Çiğdem Tekkanat; Gülfizar Sözeri Varma; Osman Ozdel; Figen C. Atesci

Schizophrenia patients with obsessive-compulsive disorder (OCD) may be a subgroup of schizophrenia, and OCD patients with poor insight may show psychotic-like symptoms. The aim of this work is to compare the neuropsychological performance of those patients with schizophrenic patients who do not have OCD symptoms and with OCD patients who have good insight. The sample consisted of 89 patients (16 OCD-schizophrenic patients, 30 non-OCD schizophrenic patients, 30 OCD patients with good insight, 13 OCD patients with poor insight). Neuropsychological evaluation included executive functions, verbal and visual memory and attention tasks. While schizophrenic patients with OCD did not differ from the non-OCD schizophrenia and OCD with poor insight groups on long-term visual and verbal memory performance, they showed poorer performance than the OCD group on long-term visual and verbal memory tests. Considering executive function, the OCD group with poor insight performed significantly worse than their counterparts with good insight, and the latter group performed better than the schizophrenia patients. The results of this study suggest that the neuropsychological performance of schizophrenia patients with OCD did not differ from that of non-OCD schizophrenic patients, and that OCD patients with poor insight were more likely to share similar cognitive characteristics with the schizophrenia groups. Our results also provide neuropsychological support for the hypothesis that OCD and schizophrenia may be a spectrum disorders.


European Neuropsychopharmacology | 2016

Executive dysfunction and cognitive subgroups in a large sample of euthymic patients with bipolar disorder

Emre Bora; Ceren Hıdıroğlu; Ayşegül Özerdem; Ömer Faruk Kaçar; Gökhan Sarısoy; Filiz Civil Arslan; Ömer Aydemir; Zeynep Cubukcuoglu Tas; Simavi Vahip; Adnan Atalay; Nuray Atasoy; Figen C. Atesci; Selim Tümkaya

Bipolar disorder (BP), at the group level, is associated with significant but modest cognitive deficits, including executive dysfunction. Among executive functions, response inhibition deficits have been suggested to be particularly relevant to BP. However, BP is associated with significant heterogeneity in neurocognitive performance and level of functioning. Very few studies have investigated neurocognitive subgroups in BP with data-driven methods rather than arbitrarily defined criteria. Other than having relatively small sample sizes, previous studies have not taken into consideration the neurocognitive variability in healthy subjects. Five-hundred-fifty-six euthymic patients with BP and 416 healthy controls were assessed using a battery of cognitive tests and clinical measures. Neurocognitive subgroups were investigated using latent class analysis, based on executive functions. Four neurocognitive subgroups, including a good performance cluster, two moderately low-performance groups, which differ in response inhibition and reasoning abilities, and a severe impairment cluster were found. In comparison to healthy controls, BP patients were overrepresented in severe impairment cluster (27% vs 5.3%) and underrepresented in good performance cluster. BP patients with lower educational attainment and older age were significantly more likely to be members of cognitively impaired subgroups. Antipsychotic use was less common in good performance cluster. These results suggest that there is a considerable overlap of cognitive functions between BP and healthy controls. Neurocognitive differences between BP and healthy controls are driven by a subgroup of patients who have severe and global, rather than selective, cognitive deficits.


Progress in Neuro-psychopharmacology & Biological Psychiatry | 2011

Neurological soft signs in obsessive compulsive disorder with good and poor insight.

Filiz Karadag; Selim Tümkaya; Duygu Kırtaş; Muharrem Efe; Huseyin Alacam; Nalan Kalkan Oguzhanoglu

OBJECTIVE Obsessive compulsive disorder (OCD) is a clinically heterogeneous disorder; OCD with poor insight has been suggested to be a specific clinical subtype. Neurological soft signs (NSSs) may be helpful to identify the specific subtypes of OCD patients. METHODS In the present study, we aimed to compare OCD patients with poor insight with OCD patients having good insight, and healthy individuals. Sixty-four OCD patients (38 with good insight and 26 with poor insight), and 32 healthy subjects were enrolled in the present study. The Overvalued Ideas Scale (OVIS) was used to determine OCD patients with poor insight. NSSs were assessed by using the Neurological Evaluation Scale (NES). RESULTS Two OCD groups had significantly higher total NES scores compared to controls (p=.000). Compared to healthy controls, OCD patients with poor insight performed significantly worse on all NES subscales, and they had significantly more NSSs on motor coordination, and sensory integration subscales compared to the OCD with good insight group. CONCLUSION Our results suggested that OCD patients with poor insight exhibit more extensive neurodevelopmental impairments compared to OCD patients with good insight.


European Psychiatry | 2012

Neurological soft signs in schizophrenia and obsessive compulsive disorder spectrum.

Selim Tümkaya; Filiz Karadag; Nalan Kalkan Oguzhanoglu

Obsessive compulsive symptoms are more frequent in patients with schizophrenia compared to normal population. Patients with obsessive compulsive disorder may also exhibit psychosis-like symptoms. Based on these findings, it has been suggested that there is a spectrum of disorders between OCD and schizophrenia. We compared two OCD groups (with good and poor insight) and two schizophrenia groups (with and without OCD) in this recommended spectrum especially in terms of neurological soft signs (NSSs) associated with sensory integration. The schizophrenia with OCD (schizo-obsessive) group exhibited worse performance than the schizophrenia group (p=0.002) in only graphesthesia tasks. Moreover, schizo-obsessive patients exhibited worse performance compared to OCD patients in terms of graphesthesia (p=0.001) and audiovisual integration (p=0.001). Interestingly, OCD patients with poor insight tended to exhibit graphesthesia deficit in a similar manner to schizo-obsessive patients rather than OCD patients. According to our results, graphesthesia disorder is strongly associated both with OCD and schizophrenia. This suggests that neurodevelopmental disorders that lead to graphesthesia disorder overlap in comorbid OCD and schizophrenia patients.


Psychiatry Research-neuroimaging | 2013

Situation awareness in obsessive-compulsive disorder

Selim Tümkaya; Filiz Karadag; Shane T. Mueller; Tugce Toker Ugurlu; Nalan Kalkan Oguzhanoglu; Osman Ozdel; Figen C. Atesci; Mustafa Bayraktutan

Past studies have suggested that OCD patients suffer memory impairment on tasks using complex stimuli that require memory for combined elements to be maintained, but not for more simplistic memory tests. We tested this with 42 OCD patients and 42 healthy controls performed a computerized situation awareness task. In addition, participants completed the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and Maudsley Obsessive-Compulsive Inventory (MOCI). The OCD patients had poorer accuracy in integration/comprehension and perception levels than controls. There were significant correlations between situational awareness scores (i.e., visuo-spatial monitoring and processing) and Y-BOCS obsession-compulsion and slowness and doubt scores of MOCI in OCD patients. In addition, there were also significant correlations between situational awareness and controlling, cleaning, slowness, rumination and total scores of MOCI in control group. Results indicated that (I) OCD patients have problems of perception, integration, and comprehension of complex visual perceptions; (II) situation awareness deficits associated with severity and prevalence of obsessions and compulsions.


Progress in Neuro-psychopharmacology & Biological Psychiatry | 2012

A proton magnetic resonance spectroscopy study in schizoaffective disorder: Comparison of bipolar disorder and schziophrenia

Demet Kalaycı; Osman Ozdel; Gülfizar Sözeri-Varma; Yilmaz Kiroglu; Selim Tümkaya

The aim of this study was to compare schizoaffective disorder, bipolar disorder and schizophrenia based on (1)H-MRS metabolite values in dorsolateral prefrontal cortex and executive functions. The subjects comprised 15 patients with bipolar disorder type I (BD), 15 with schizophrenia (SCH), 15 with schizoaffective disorder (SAD) and 15 healthy controls. We performed proton magnetic resonance spectroscopy ((1)H-MRS) of the dorsolateral prefrontal cortex (DLPFC) bilaterally. Levels of N-acetyl aspartate (NAA), choline-containing compounds (Cho) and creatine-containing compounds (Cr) were measured in the DLPFC using (1)H-MRS. We administered the Wisconsin Card Sorting Test (WCST) and the Stroop Test (ST) to evaluate executive functions. The SAD, BD and SCH patients had lower levels of NAA than the control group. The SAD and BD patients had low levels of Cho compared to the control group. The left DLPFC Cr levels in all of the patient groups and the right DLPFC Cr levels in the BD and SAD groups were lower than in the control group. The levels of NAA Cho and Cr were not related to executive functions and attention performance. Cr level were related to attention processes, only in SCH. Our results indicate that NAA levels are reduced in schizoaffective disorder, bipolar disorder and schizophrenia, but the reduction in the levels of NAA is not a distinctive feature among these three illnesses. Schizoaffective and bipolar disorders have similar features related to the levels of compounds containing Cho and Cr. This similarity may be related to these illnesses both having an affective basis.


Comprehensive Psychiatry | 2014

Involuntary social cue integration in patients with obsessive compulsive disorder

Selim Tümkaya; Filiz Karadag; Tjeerd Jellema; Nalan Kalkan Oguzhanoglu; Osman Ozdel; Figen C. Atesci; Gülfizar Sözeri Varma

OBJECTIVE Patients with obsessive compulsive disorder (OCD) have inferior social functioning compared to healthy controls, but the exact nature of these social deficits, and the underpinning mechanisms, are unknown. We sought to investigate social functioning in patients with OCD by measuring their involuntary/spontaneous processing of social cues using a specifically designed test, which might reveal deficits in these patients that explicit voluntary tasks do not detect. METHODS The sample of the study consisted of an OCD group (n = 25) and a control group (n = 26). Both groups performed an adaptation of the Social Distance Judgment Task (SDJT; Jellema et al., 2009), in which participants have to judge the geometrical distance between two human cartoon figures presented on a computer screen. Head/gaze direction and body direction were manipulated to be either compatible, i.e. both directed to the left or to the right (Compatible condition) or incompatible, i.e. body directed toward the observer (frontal view) and head/gaze directed to the left or right (Incompatible condition). RESULTS In the Compatible condition, controls nor OCD patients were influenced by the social cues in their judgments of the geometrical distances. However, in the Incompatible condition, where the attentional cue was more conspicuous, both groups were influenced by the cues, but the controls to a significantly larger extent than the OCD patients. CONCLUSIONS This study showed that patients with OCD are less likely, compared to controls, to automatically/spontaneously integrate the others direction of attention into their visual percept. This may have resulted in their judgments of the geometrical distances between the agents to be more accurate than those of controls. The suggested impairment in automatically integrating social cues may have important repercussions for the social functioning of OCD patients.


Neural Regeneration Research | 2012

Neurochemical metabolites in the medial prefrontal cortex in bipolar disorder: A proton magnetic resonance spectroscopy study

Osman Ozdel; Demet Kalaycı; Gülfizar Sözeri-Varma; Yilmaz Kiroglu; Selim Tümkaya; Tuğçe Toker-Uğurlu

The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.


Psychiatry Investigation | 2018

Modafinil Dependence: A Case with Attention-Deficit/Hyperactivity Disorder

Huseyin Alacam; Omer Basay; Selim Tümkaya; Mehmet Mart; Gokce Kar

Modafinil is generally known as a drug with low addiction potential. There are few case reports in the literature demonstrating that Modafinil, stated being capable of diminishing symptoms of attention deficit/hyperactivity disorder (ADHD), causes addiction. In the present article a Modafinil addicted ADHD case, consuming usurious doses (5,000 mg/per day) of Modafinil is presented. The case presented to our psychiatry outpatient clinic due to: requirement of in taking high dose Modafinil in order to achieve the initial effects, difficulty in obtaining the drug, irritability, anxiousness, sleep irregularities, fatigue and unpleasant vivid dreams when he did not use the drug. It was realized that the patient, himself increased doses of Modafinil incrementally, in order to keep its effects on attention symptoms at the same level. It has to be kept in mind that ADHD patients can develop Modafinil addiction. It is necessary to carry out systemic studies on this subject.


Archives of Neuropsychiatry | 2018

Metacognitive Beliefs and Their Relation with Symptoms in Obsessive-Compulsive Disorder

Selim Tümkaya; Filiz Karadag; ezgi hanci yenigun; Osman Ozdel; Himani Kashyap

Introduction Metacognitive constructs have shown promise in explaining the symptoms of Obsessive-Compulsive Disorder (OCD). Few studies have examined the role of metacognitions in symptom dimensions of OCD, despite mounting clinical, neuropsychological and imaging evidence for the distinctiveness of these dimensions. Methods Metacognitions were assessed using the Metacognitions Questionnaire (MCQ-30) in 51 participants with DSM IV OCD and 46 healthy controls. The Maudsley Obsessional Compulsive Inventory (MOCI) was used to quantify symptom dimensions, along with the Hamilton Anxiety Rating Scale (HAM-A) for anxiety, and Hamilton Depression Rating Scale (HAM-D) for depression. Results Individuals with OCD differed from healthy controls on beliefs of uncontrollability and danger when depression and anxiety were controlled for. Correlations between metacognitive beliefs and obsessive-compulsive symptom dimensions were largely similar across the OCD and healthy control groups. Hierarchical regression showed that need to control thoughts contributed to checking, cleaning and rumination symptoms; cognitive self-consciousness to symptoms of slowness; uncontrollability and danger to doubt symptoms; positive beliefs to checking symptoms. Conclusions Specific associations between metacognitive variables and the different symptom dimensions of OCD are evident, however, severity of anxiety and depression also contribute to these associations.

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Emre Bora

Dokuz Eylül University

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