Social anxiety in online interactions: an RDoC-informed systematic review of research methods and analysis of the effects of transcranial direct current stimulation on anxiety, affect and speech

Abstract

Social anxiety disorder (SAD) is highly prevalent, impairing and resistant to treatment. Technological advances offer new possibilities for assessment and intervention, but clinical integration of empirical advancement remains limited. This thesis applies the Research Domain Criteria (RDoC) framework to explore computer-based methods for studying SAD and neurostimulation as a potential intervention.
The first study presents a systematic review of 16 papers which use remote methods to research SAD. It reveals methodological variety including video and text-based interactions, and pre-recorded stimuli. We discuss the efficacy of paradigms in evoking anxiety and collecting subjective and objective data. The techniques map to the RDoC matrix and highlight future research possibilities. We highlight the value of multimodal remote research and importance of controlled, ecologically valid interactions which specifically induce social anxiety and facilitate objective data collection.
The second investigation empirically explores the effect of transcranial direct current stimulation (tDCS) on anxiety, affect and speech during an online interaction under social-evaluative threat in a double-blind, between-subjects study. Participants (n = 90) aged 18-45 were randomly allocated to receive bilateral, unilateral, or sham stimulation of the dorsolateral prefrontal cortex (dlPFC). Anxiety and affect were self-reported. Interaction speech was recorded, analysed using Linguistic Inquiry and Word Count (LIWC) software, and mapped to RDoC domains. Neither stimulation condition had a measurable effect on subjective anxiety or mood. We found that unilateral stimulation influenced linguistic markers of anxiety, increasing Cognitive Systems and decreasing Social Processes speech. Our results highlight advantages of multimodal SAD research over research relying solely on self-report, specifically linguistic analysis. Findings suggest stimulation of the left dlPFC increases cognitive-processing and decreases social vigilance manifested in speech, but bilateral stimulation including inhibition of cortical activity in the right dlPFC nullified these benefits.
This thesis demonstrates the potential of digital research and neurostimulation in measuring and modulating SAD.
Keywords: social anxiety, online, multimodal, transcranial direct current stimulation, dorsolateral prefrontal cortex, speech analysis, linguistic inquiry and word count, research domain criteria

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Identifiers

ORCID for Matthew Garner: orcid.org/0000-0001-9481-2226

ORCID for Nathan Huneke: orcid.org/0000-0001-5981-6707

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