A Narrative Review of Network Studies in Depression: What Different Methodological Approaches Tell Us About Depression

The network theory of psychopathology proposes that mental disorders arise from direct interactions between symptoms. This theory provides a promising framework to understand the development and maintenance of mental disorders such as depression. In this narrative review, we summarize the literature on network studies in the field of depression. Four methodological network approaches are distinguished: (i) studies focusing on symptoms at the macro-level vs. (ii) on momentary states at the micro-level, and (iii) studies based on cross-sectional vs. (iv) time-series (dynamic) data. Fifty-six studies were identified. We found that different methodological approaches to network theory yielded largely inconsistent findings on depression. Centrality is a notable exception: the majority of studies identified either positive affect or anhedonia as central nodes. To aid future research in this field, we outline a novel complementary network theory, the momentary affect dynamics (MAD) network theory, to understand the development of depression. Furthermore, we provide directions for future research and discuss if and how networks might be used in clinical practice. We conclude that more empirical network studies are needed to determine whether the network theory of psychopathology can indeed enhance our understanding of the underlying structure of depression and advance clinical treatment.

AIM against survey fraud

Objectives Although there exists a variety of anonymous survey software, this study aimed to develop an improved system that incentivizes responses and proactively detects fraud attempts while maintaining anonymity. Materials and Methods The Anonymous Incentive Method (AIM) was designed to utilize a Secure Hash Algorithm, which deterministically assigned anonymous identifiers to respondents. An anonymous raffle system was established to randomly select participants for a reward. Since the system provided participants with their unique identifiers and passwords upon survey completion, participants were able to return to the survey website, input their passwords, and receive their rewards at a later date. As a case study, the validity of this novel approach was assessed in an ongoing study on vaping in high school friendship networks. Results AIM successfully assigned irreversible, deterministic identifiers to survey respondents. Additionally, the particular case study used to assess the efficacy of AIM verified the deterministic aspect of the identifiers. Discussion Potential limitations, such as scammers changing the entry used to create the identifier, are acknowledged and given practical mitigation protocols. Although AIM exhibits particular usefulness for network studies, it is compatible with a wide range of applications to help preempt survey fraud and expedite study approval. Conclusion The improvements introduced by AIM are 2-fold: (1) duplicate responses can be filtered out while maintaining anonymity and (2) the requirement for the participant to keep their identifier and password for some time before returning to the survey website to claim a reward ensures that rewards only go to actual respondents.

The Usage of OHDSI OMOP – A Scoping Review

OHDSI, a fast growing open-science research community seeks to enable researchers from around the globe to conduct network studies based on standardized data and vocabularies. There is no comprehensive review of publications about OHDSI’s standard: the OMOP Common Data Model and its usage available. In this work we aim to close this gap and provide a summary of existing publications including the analysis of its meta information such as the choice of journals, journal types, countries, as well as an analysis by topics based on a title and abstract screening. Since 2016, the number of publications has been constantly growing and the relevance of the OMOP CDM is increasing in terms of multi-country studies based on observational patient data.

Why Do Homogeneous Friendships Persist in a Diverse Population? Making Sense of Homophily

Homophily is one of the robust findings in social network studies. It persists even in a diverse population where the opportunity to develop homogeneous friendship is not greater than a mere chance and the process of developing heterogeneous friendship is facilitated. In this study, we introduce the Framework for Intergroup Relations and Multiple Affiliations Networks (FIRMAN), derived from social identity theory and social network framework, that can explain why that is the case. We begin by explaining its components: social identity space, social identity distance, length of ties, tie outreachability, and tie capacity. Then, through 7000 agent-based simulations, we demonstrate how the interaction of tie outreachability and tie capacity constraints heterogeneous friendship formations, which in turn make homophily inevitable even in a very diverse population. Surprisingly, the presence of even a small percentage (< 15%) of agents who can only develop homogeneous friendships can affect the whole population, preventing other agents from developing heterogenous friendships. We conclude by providing some directions for future research.

Stepwise neuronal network pattern formation in agarose gel during cultivation using non-destructive microneedle photothermal microfabrication

Conventional neuronal network pattern formation techniques cannot control the arrangement of axons and dendrites because network structures must be fixed before neurite differentiation. To overcome this limitation, we developed a non-destructive stepwise microfabrication technique that can be used to alter microchannels within agarose to guide neurites during elongation. Micropatterns were formed in thin agarose layer coating of a cultivation dish using the tip of a 0.7 $$\upmu \mathrm{m}$$ μ m -diameter platinum-coated glass microneedle heated by a focused 1064-nm wavelength infrared laser, which has no absorbance of water. As the size of the heat source was 0.7 $$\upmu \mathrm{m}$$ μ m , which is smaller than the laser wavelength, the temperature fell to 45 $$^\circ \hbox {C}$$ ∘ C within a distance of 7.0 $$\upmu \mathrm{m}$$ μ m from the edge of the etched agarose microchannel. We exploited the fast temperature decay property to guide cell-to-cell connection during neuronal network cultivation. The first neurite of a hippocampal cell from a microchamber was guided to a microchannel leading to the target neuron with stepwise etching of the micrometer resolution microchannel in the agarose layer, and the elongated neurites were not damaged by the heat of etching. The results indicate the potential of this new technique for fully direction-controlled on-chip neuronal network studies.