Despite the concern that has been expressed about potential method biases, and the pervasiveness of research settings with the potential to produce them, there is disagreement about whether they really are a problem for researchers in the behavioral sciences. Therefore, the purpose of this review is to explore the current state of knowledge about method biases. First, we explore the meaning of the terms “method” and “method bias” and then we examine whether method biases influence all measures equally. Next, we review the evidence of the effects that method biases have on individual measures and on the covariation between different constructs. Following this, we evaluate the procedural and statistical remedies that have been used to control method biases and provide recommendations for minimizing method bias.

Sources of Method Bias in Social Science Research and Recommendations on How to Control It

Schizophrenia is a highly heritable disorder. Genetic risk is conferred by a large number of alleles, including common alleles of small effect that might be detected by genome-wide association studies. Here we report a multi-stage schizophrenia genome-wide association study of up to 36,989 cases and 113,075 controls. We identify 128 independent associations spanning 108 conservatively defined loci that meet genome-wide significance, 83 of which have not been previously reported. Associations were enriched among genes expressed in brain, providing biological plausibility for the findings. Many findings have the potential to provide entirely new insights into aetiology, but associations at DRD2 and several genes involved in glutamatergic neurotransmission highlight molecules of known and potential therapeutic relevance to schizophrenia, and are consistent with leading pathophysiological hypotheses. Independent of genes expressed in brain, associations were enriched among genes expressed in tissues that have important roles in immunity, providing support for the speculated link between the immune system and schizophrenia.

/pdf/biological-insights-from-108-schizophrenia-associated-3rfvth8dm9.pdf

Biological insights from 108 schizophrenia-associated genetic loci

https://bic.berkeley.edu/sites/default/files/Rossi_09_TMS%20safety%20review.pdf

Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research

Binge eating disorder (BED) is characterized by recurrent episodes of binge eating and, subsequently, significant psychological distress (e.g., shame, guilt). Recently recognized by the American Psychiatric Association (APA) as a distinct eating disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), BED is considered a significant public health problem independently and for its impact on obesity and diabetes. The related problem, loss-of-control (LOC) eating, describes recurrent binge-like eating behavior in individuals who cannot meet full criteria for BED such as post-bariatric surgery patients and children. LOC eating has detrimental psychological and physical health effects, including significant distress and symptoms of depression, as well as excess weight gain in children and suboptimal weight loss and weight regain in post-bariatric patients. Table 1 lists the diagnostic criteria for BED (as defined in the current DSM-5 and earlier, in the DSM, Fourth Edition [DSM-IV]) and frequently-used definitions of LOC eating.

Diagnostic and statistical manual of mental disorders, fifth edition

Current diagnostic systems for mental disorders rely upon presenting signs and symptoms, with the result that current definitions do not adequately reflect relevant neurobiological and behavioral systems - impeding not only research on etiology and pathophysiology but also the development of new treatments. The National Institute of Mental Health began the Research Domain Criteria (RDoC) project in 2009 to develop a research classification system for mental disorders based upon dimensions of neurobiology and observable behavior. RDoC supports research to explicate fundamental biobehavioral dimensions that cut across current heterogeneous disorder categories. We summarize the rationale, status and long-term goals of RDoC, outline challenges in developing a research classification system (such as construct validity and a suitable process for updating the framework) and discuss seven distinct differences in conception and emphasis from current psychiatric nosologies. Future diagnostic systems cannot reflect ongoing advances in genetics, neuroscience and cognitive science until a literature organized around these disciplines is available to inform the revision efforts. The goal of the RDoC project is to provide a framework for research to transform the approach to the nosology of mental disorders.

/pdf/toward-the-future-of-psychiatric-diagnosis-the-seven-pillars-30e28e7cj4.pdf

Toward the future of psychiatric diagnosis: the seven pillars of RDoC

/pdf/research-domain-criteria-rdoc-toward-a-new-classification-59j2rllxst.pdf

Research domain criteria (RDoC): toward a new classification framework for research on mental disorders

Objective: The purpose of this study was to describe the clinical characteristics of a novel group of patients with obsessive-compulsive disorder (OCD) and tic disorders, designated as pediatric autoimmune neuropsychiatric disorders associated with streptococcal (group A β-hemolytic streptococcal [GABHS]) infections (PANDAS). Method: The authors conducted a systematic clinical evaluation of 50 children who met all of the following five working diagnostic criteria: presence of OCD and/or a tic disorder, prepubertal symptom onset, episodic course of symptom severity, association with GABHS infections, and association with neurological abnormalities. Results: The children’s symptom onset was acute and dramatic, typically triggered by GABHS infections at a very early age (mean=6.3 years, SD=2.7, for tics; mean=7.4 years, SD=2.7, for OCD). The PANDAS clinical course was characterized by a relapsing-remitting symptom pattern with significant psychiatric comorbidity accompanying the exacerbations; emotional lability, separation anxiety, nighttime fears and bedtime rituals, cognitive deficits, oppositional behaviors, and motoric hyperactivity were particularly common. Symptom onset was triggered by GABHS infection for 22 (44%) of the children and by pharyngitis (no throat culture obtained) for 14 others (28%). Among the 50 children, there were 144 separate episodes of symptom exacerbation; 45 (31%) were associated with documented GABHS infection, 60 (42%) with symptoms of pharyngitis or upper respiratory infection (no throat culture obtained), and six (4%) with GABHS exposure. Conclusions: The working diagnostic criteria appear to accurately characterize a homogeneous patient group in which symptom exacerbations are triggered by GABHS infections. The identification of such a subgroup will allow for testing of models of pathogenesis, as well as the development of novel treatment and prevention strategies. (Am J Psychiatry 1998; 155:264‐271)

https://ajp.psychiatryonline.org/doi/pdfplus/10.1176/ajp.155.2.264

Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections: Clinical Description of the First 50 Cases

There exists a divide between findings from integrative neuroscience and clinical research focused on mechanisms of psychopathology. Specifically, a clear correspondence does not emerge between clusters of complex clinical symptoms and dysregulated neurobiological systems, with many apparent redundancies. For instance, many mental disorders involve multiple disruptions in putative mechanistic factors (e.g., excessive fear, deficient impulse control), and different disrupted mechanisms appear to play major roles in many disorders. The Research Domain Criteria (RDoC) framework is a heuristic to facilitate the incorporation of behavioral neuroscience in the study of psychopathology. Such integration might be achieved by shifting the central research focus of the field away from clinical description to more squarely examine aberrant mechanisms. RDoC first aims to identify reliable and valid psychological and biological mechanisms and their disruptions, with an eventual goal of understanding how anomalies in these mechanisms drive psychiatric symptoms. This approach will require new methods to ascertain samples, relying on hypothesized psychopathological mechanisms to define experimental groups instead of traditional diagnostic categories. RDoC, by design, uncouples research efforts from clinically familiar categories to focus directly on fundamental mechanisms of psychopathology. RDoC proposes a matrix of domains and levels of analyses and invites the field to test and refine the framework. If RDoC is successful, the domains will ultimately relate to familiar psychopathologies in ways that promote new knowledge regarding etiology and more efficient development of new preventive and treatment interventions.

/pdf/developing-constructs-for-psychopathology-research-research-31asgdvqwl.pdf

Developing constructs for psychopathology research: research domain criteria.

Therapeutic plasma exchange and intravenous immunoglobulin for obsessive-compulsive disorder and tic disorders in childhood.

OBJECTIVE: The authors assessed selective basal ganglia involvement in a subgroup of children with obsessive-compulsive disorder (OCD) and/or tics believed to be associated with streptococcal infection. METHOD: Using computer-assisted morphometric techniques, they analyzed the cerebral magnetic resonance images of 34 children with presumed streptococcus-associated OCD and/or tics and 82 healthy comparison children who were matched for age and sex. RESULTS: The average sizes of the caudate, putamen, and globus pallidus, but not of the thalamus or total cerebrum, were significantly greater in the group of children with streptococcus-associated OCD and/or tics than in the healthy children. The differences were similar to those found previously for subjects with Sydenham’s chorea compared with normal subjects. CONCLUSIONS: These results support the hypothesis that there is a distinct subgroup of subjects with OCD and/or tics who have enlarged basal ganglia. These findings are consistent with the hypothesis of...

https://pandasweb.nl/cfsystem/userData/literatuur/1319009463__document__mristudy-swedo-20002811.pdf

Marjorie A. Garvey

Papers

Research domain criteria (RDoC): toward a new classification framework for research on mental disorders

Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections: Clinical Description of the First 50 Cases

Developing constructs for psychopathology research: research domain criteria.

Therapeutic plasma exchange and intravenous immunoglobulin for obsessive-compulsive disorder and tic disorders in childhood.

MRI assessment of children with obsessive-compulsive disorder or tics associated with streptococcal infection.