Abnormal Structural Network Communication Reflects Cognitive Deficits in Schizophrenia.

Schizophrenia has long been thought to be a disconnection syndrome and several previous studies have reported widespread abnormalities in white matter tracts in individuals with schizophrenia. Furthermore, reductions in structural connectivity may also impair communication between anatomically unconnected pairs of brain regions, potentially impacting global signal traffic in the brain. Therefore, we used different communication models to examine direct and indirect structural connections (polysynaptic) communication in large-scale brain networks in schizophrenia. Diffusion-weighted magnetic resonance imaging scans were acquired from 62 patients diagnosed with schizophrenia and 35 controls. In this study, we used five network communication models including, shortest paths, navigation, diffusion, search information and communicability to examine polysynaptic communication in large-scale brain networks in schizophrenia. We showed less efficient communication between spatially widespread brain regions particulary encompassing cortico-subcortical basal ganglia network in schizophrenia group relative to controls. Then, we also examined whether reduced communication efficiency was related to clinical symptoms in schizophrenia group. Among different measures of communication efficiency, only navigation efficiency was associated with global cognitive impairment across multiple cognitive domains including verbal learning, processing speed, executive functions and working memory, in individuals with schizophrenia. We did not find any association between communication efficiency measures and positive or negative symptoms within the schizophrenia group. Our findings are important for improving our mechanistic understanding of neurobiological process underlying cognitive symptoms in schizophrenia.

Negative symptoms are associated with modularity and thalamic connectivity in schizophrenia.

Negative symptoms, including avolition, anhedonia, asociality, blunted affect and alogia are associated with poor long-term outcome and functioning. However, treatment options for negative symptoms are limited and neurobiological mechanisms underlying negative symptoms in schizophrenia are still poorly understood. Diffusion-weighted magnetic resonance imaging scans were acquired from 64 patients diagnosed with schizophrenia and 35 controls. Global and regional network properties and rich club organization were investigated using graph analytical methods. We found that the schizophrenia group had higher modularity, clustering coefficient and characteristic path length, and lower rich connections compared to controls, suggesting highly connected nodes within modules but less integrated with nodes in other modules in schizophrenia. We also found a lower nodal degree in the left thalamus and left putamen in schizophrenia relative to the control group. Importantly, higher modularity was associated with greater negative symptoms but not with cognitive deficits in patients diagnosed with schizophrenia suggesting an alteration in modularity might be specific to overall negative symptoms. The nodal degree of the left thalamus was associated with both negative and cognitive symptoms. Our findings are important for improving our understanding of abnormal white-matter network topology underlying negative symptoms in schizophrenia.

Dermatological aspects of synthetic cannabinoid addiction.

CONTEXT: Synthetic cannabinoids (SCs) have recently become one of the most abused substances among young population and have caused severe health consequences in our country and worldwide. OBJECTIVE: The aim of this study was to investigate sociodemographic and dermatological findings in SC addicts. MATERIALS AND METHODS: A total of 136 SC users who applied to our hospital's Substance Dependence Center outpatient clinic and diagnosed with drug addiction according to DSM-4 criteria between September 2014 and September 2015 were enrolled to our study. Patients were evaluated by dermatologist and psychiatrist with sociodemographic and clinical data sheets. Data were obtained by direct conversation with patients, clinical examination findings, and laboratory tests, if necessary. RESULTS: Of 136 patients, 12 (8.8%) were female and 124 (91.2%) were male, aged between 17 and 53 with mean age of 25.8 ± 9.2. Most common use way of SC was smoking and patients majorly used opiates before SC. The majority of the patients enrolled to our study were low-educated and almost 50% did not have a regular job. The most frequent dermatologic complaints were periorbital darkening, hallowed-cheeks and premature aging, hair loss and gray hair, and acnes, whereas most frequent dermatologic examination findings were artifact lesions such as blade scars and tobacco scars-stains, tattoos, and acnes. DISCUSSION AND CONCLUSIONS: Given the increased prevalence of SC use in our country and around the world, dermatologists should continue to familiarize themselves with the common mucocutaneous markers of this substance use. Awareness of signs of SCs use will facilitate earlier diagnose, intervention, and directed treatment.

Facial emotion recognition deficits in abstinent cannabis dependent patients.

BACKGROUND: Cannabis is clearly the most popular illicit drug in North America, Europe and in other parts of the world. Evidence is accumulating for the involvement of the endocannabinoid system in emotional processing. However, only few studies examined emotional processing in chronic, heavy cannabis users and these studies were performed in cannabis dependent patients who were abstinent for 12-48 hours. The aim of this study was to investigate facial emotion identification and discrimination abilities in patients with cannabis dependence who were abstinent for at least 1 month. METHODS: The study included 30 males with cannabis dependency according to DSM-IV criteria and who had been abstinent for at least 1 month and 30 healthy controls. All the subjects were evaluated with Facial Emotion Identification Test (FEIT) and Facial Emotion Discrimination Test (FEDT). RESULTS: The main finding of this study was the presence of deficits in both identification and discrimination of facial emotions in cannabis dependent patients during abstinence. In addition, when we examined negative and positive emotions separately, we found out that abstinent cannabis dependent patients performed significantly worse than controls in the identification of negative emotions but not positive emotions. CONCLUSIONS: Our findings indicate that facial emotion recognition deficits which have previously been observed in current cannabis users are still detectable in abstinent cannabis dependent patients and do not improve quickly with abstinence (an average of 3.2 months).

Effort-cost decision-making associated with negative symptoms in schizophrenia and bipolar disorder.

Motivational deficits and reduced goal-directed behavior for external rewards have long been considered an important features of negative symptoms in patients with schizophrenia (SCZ). Negative symptoms have also a high prevalence in bipolar disorder (BP). We used a transdiagnostic approach in order to examine association between negative symptoms and effort allocation for monetary rewards. 41 patients with SCZ and 34 patients with BP were enrolled in the study along with 41 healthy controls (HC). Effort-Expenditure for Rewards Task (EEfRT) was used to measure subjects' effort allocation for monetary rewards. Generalized estimating equation models were used to analyze EEfRT choice behavior. Negative symptoms were assessed using the Brief Negative Symptom Scale (BNSS). SCZ and BP groups expended lower effort to obtain a monetary rewards compared to HC. Severity of negative symptoms was negatively correlated with EEfRT performance in both diagnostic groups. Each diagnostic group showed lower effort allocation for monetary rewards compared to HC suggesting reduced motivation for monetary rewards. In addition, our results suggest that abnormal effort-based decision-making might be a transdiagnostic factor underlying negative symptoms.

Reduced sensitivity but intact motivation to monetary rewards and reversal learning in obesity.

BACKGROUND: Obesity has been linked to altered reward processing but little is known about which components of reward processing including motivation, sensitivity and learning are impaired in obesity. We examined whether obesity compared to healthy weight controls is associated with differences in distinct subdomains of reward processing. To this end, we used two established paradigms, namely the Effort Expenditure for Rewards task (EEfRT) and the Probabilistic Reversal Learning Task (PRLT). METHODS: 30 individuals with obesity (OBS) and 30 healthy weight control subjects (HC) were included in the study. Generalized estimating equation models were used to analyze EEfRT choice behavior. PRLT data was analyzed using both conventional behavioral variables of choices and computational models. RESULTS: Our findings from the different tasks speak in favor of a hyposensitivity to non-food rewards in obesity. OBS did not make fewer overall hard task selections compared to HC in the EEfRT suggesting generally intact non-food reward motivation. However, in highly rewarding trials (i.e.,trials with high reward magnitude and high reward probability),OBSmadefewer hard task selections compared to normal weight subjects suggesting decreased sensitivity to highly rewarding non-food reinforcers. Hyposensitivity to non-food rewards was also evident in OBS in the PRLT as evidenced by lower win-stay probability compared to HC. Our computational modelling analyses revealed decreased stochasticity but intact reward and punishment learning rates in OBS. CONCLUSIONS: Our findings provide evidence for intact reward motivation and learning in OBS but lower reward sensitivity which is linked to stochasticity of choices in a non-food context. These findings might provide further insight into the mechanism underlying dysfunctional choices in obesity.

Neural correlates of mental state decoding and mental state reasoning in schizophrenia.

Theory of mind skills are disrupted in schizophrenia. However, various theory of mind tasks measure different neurocognitive domains. This multimodal neuroimaging study aimed to investigate the neuroanatomical correlates of mental state decoding and reasoning components of theory of mind in schizophrenia and healthy controls (HCs) using T1-weighted and diffusion-weighted (DTI) magnetic resonance imaging (MRI). Sixty-two patients with schizophrenia and 34 HCs were included. The Reading the Mind in the Eyes (RMET) and Hinting tests were used to evaluate mental state decoding and reasoning, respectively. Correlations between social cognition and cortical parameters (thickness, volume, surface area), or DTI scalars (fractional anisotropy, axial diffusivity, radial diffusivity) were cluster-based corrected for multiple comparisons. In schizophrenia, RMET scores showed positive correlations in 3 clusters, including left insula thickness, right superior-temporal thickness, left superior-temporal-sulcus volume, and DTI analysis revealed that fractional anisotropy showed positive correlations in 3 clusters, including right inferior-fronto-occipital fasciculus, left forceps-major, left inferior-fronto-occipital fasciculus. In schizophrenia, Hinting test scores showed positive correlations in 3 clusters in T1-weighted MRI, including left superior-temporal-sulcus volume, left superior-temporal-sulcus surface area, left pars-orbitalis volume. In conclusion, this study provided evidence for the involvement of particular cortical regions and white matter tracts in mental state decoding and reasoning.

Computational analysis of probabilistic reversal learning deficits in male subjects with alcohol use disorder.

Background: Alcohol use disorder is characterized by perseverative alcohol use despite negative consequences. This hallmark feature of addiction potentially relates to impairments in behavioral flexibility, which can be measured by probabilistic reversal learning (PRL) paradigms. We here aimed to examine the cognitive mechanisms underlying impaired PRL task performance in patients with alcohol use disorder (AUDP) using computational models of reinforcement learning. Methods: Twenty-eight early abstinent AUDP and 27 healthy controls (HC) performed an extensive PRL paradigm. We compared conventional behavioral variables of choices (perseveration; correct responses) between groups. Moreover, we fitted Bayesian computational models to the task data to compare differences in latent cognitive variables including reward and punishment learning and choice consistency between groups. Results: AUDP and HC did not significantly differ with regard to direct perseveration rates after reversals. However, AUDP made overall less correct responses and specifically showed decreased win-stay behavior compared to HC. Interestingly, AUDP showed premature switching after no or little negative feedback but elevated proneness to stay when accumulation of negative feedback would make switching a more optimal option. Computational modeling revealed that AUDP compared to HC showed enhanced learning from punishment, a tendency to learn less from positive feedback and lower choice consistency. Conclusion: Our data do not support the assumption that AUDP are characterized by increased perseveration behavior. Instead our findings provide evidence that enhanced negative reinforcement and decreased non-drug-related reward learning as well as diminished choice consistency underlie dysfunctional choice behavior in AUDP.

Clinical Characteristics, Comorbid Medical Diagnoses, and Causes of Death of Individuals with Severe Mental Illness Who Died During Follow-up in Community Mental Health Centers: A Multicenter, Retrospective Study. / Toplum Ruh Sagligi Merkezlerinde Takipleri Sirasinda Ölen Siddetli Ruhsal Hastaligi Olan Bireylerin Klinik Özellikleri, Ek Tibbi Tanilari ve Ölüm Nedenleri: Çok Merkezli, Geriye Dönük Bir Arastirma.

OBJECTIVE: In this study, it was aimed to define the clinical characteristics, causes of death, disease and treatment of patients who died while being followed for severe mental illness. METHOD: The study was carried out in ten community mental health centers from six provinces. The clinical characteristics, causes of death, course of the illness and treatment characteristics of the patients who had a death report from the date the community mental health centers were opened until the start date of the study were analyzed by retrospective file scanning method. RESULTS: In an average of 52 months, files of 3715 patients were examined. There were death declarations for 106 patients. The diagnosis of most patients with death declarations was schizophrenia (78%), most of them were male (66%), mean age was 57, mean disease duration was 24 years. The rate of multiple antipsychotic medication use was 61%. The most common comorbidities were metabolic syndrome (36%), hypertension (22%), diabetes (18%) and chronic obstructive pulmonary disease (15%). The most frequently reported causes of death were cardiovascular diseases (39%), infectious diseases (14%) and cancer (11%). CONCLUSION: Individuals with severe mental illness followed up in community mental health centers are mostly die due to preventable natural causes of death. Therefore, a sensitive approach should be taken to evaluate psychiatric and other medical conditions together. In our country, there is a need for natural follow-up studies investigating the average age of death and causes of death of individuals with severe mental illness.

An unusual suicide attempt: a case with psychosis during an acute porphyric attack.

The porphyrias are a heterogeneous group of disorders characterized by abnormal heme biosynthesis. Although all subtypes are rare, acute intermittent porphyria (AIP) is the most common form of the neuroporphyrias. Abdominal pain, peripheral neuropathy, and changes in cognitive function are the classical triad of an acute porphyric attack but the variability of the symptoms may interfere with the diagnosis of AIP. Delayed diagnosis and treatment of acute porphyric attacks, however, can be fatal or may cause long-term or permanent neurological damage. We hereby report a case of 45-year-old male with suicide attempt because of his psychotic symptoms during an AIP attack.