Background: Panic disorder (PD) is a kind of anxiety disorder that impacts the life quality
and functional perspectives in patients. However, the pathophysiological study of PD seems still
inadequate and many unresolved issues need to be clarified.
Objectives: In this review article of biomarkers in PD, the investigator will focus on the findings of
magnetic resonance imaging (MRI) of the brain in the pathophysiology study. The MRI biomarkers
would be divided into several categories, on the basis of structural and functional perspectives.
Methods: The structural category would include the gray matter and white matter tract studies. The
functional category would consist of functional MRI (fMRI), resting-state fMRI (Rs-fMRI), and
magnetic resonance spectroscopy (MRS). The PD biomarkers revealed by the above methodologies
would be discussed in this article.
Results: For the gray matter perspectives, the PD patients would have alterations in the volumes of
fear network structures, such as the amygdala, parahippocampal gyrus, thalamus, anterior cingulate
cortex, insula, and frontal regions. For the white matter tract studies, the PD patients seemed to have
alterations in the fasciculus linking the fear network regions, such as the anterior thalamic radiation,
uncinate fasciculus, fronto-occipital fasciculus, and superior longitudinal fasciculus. For the fMRI
studies in PD, the significant results also focused on the fear network regions, such as the amygdala,
hippocampus, thalamus, insula, and frontal regions. For the Rs-fMRI studies, PD patients seemed to
have alterations in the regions of the default mode network and fear network model. At last, the
MRS results showed alterations in neuron metabolites of the hippocampus, amygdala, occipital
cortex, and frontal regions.
Conclusion: The MRI biomarkers in PD might be compatible with the extended fear network model
hypothesis in PD, which included the amygdala, hippocampus, thalamus, insula, frontal regions, and