Cortical thickness reductions in the middle frontal cortex in patients with panic disorder

BACKGROUND

Panic disorder (PD), an anxiety disorder characterized by the recurrence of panic attacks, has been reported to be associated with volumetric changes in several brain regions. There are, however, very few studies investigating abnormalities in cortical thickness, and little is known about the relationship between cortical thickness and social dysfunction in PD.

METHODS

Thirty-eight patients with PD and 38 healthy control participants (HC) were recruited for this study. A whole-brain analysis was performed to evaluate groupwise differences in cortical thickness using the FreeSurfer software. Symptom severity and social functioning were evaluated with the Panic Disorder Severity Scale (PDSS) and the Global Assessment of Functioning (GAF) scale.

RESULTS

The patients with PD demonstrated a significant reduction in cortical thickness in the left rostral middle frontal cortex (MFC), compared with the HC. Correlational analyses revealed that cortical thickness in the left rostral MFC showed a significant negative relationship with PDSS score and a significant positive relationship with GAF scores in the PD patients.

LIMITATIONS

All the patients received medication.

CONCLUSION

PD patients showed reduced cortical thickness in the left rostral MFC compared with HC. Furthermore, cortical thickness in this region was associated with patients' symptom severity and degree of social dysfunction.

Substance abuse risk in emerging adults associated with smaller frontal gray matter volumes and higher externalizing behaviors

BACKGROUND

During emerging adulthood, alcohol and substance use peak. Previous research has suggested that prefrontal and subcortical brain volumes may relate to risk for development of substance abuse. Epidemiological studies indicate that early initiation of alcohol or drug use significantly increases the likelihood of later substance use disorder diagnoses. We hypothesized that frontal regions would be smaller in young adults with early substance use and related problems (early-risk, ER), compared with a control group without early use/problems (C). We further hypothesized that these volumes would be associated with more externalizing behaviors, an additional robust predictor of substance abuse.

METHODS

One hundred and six subjects, ages 18-23, underwent high-resolution anatomical magnetic resonance image scanning. Individuals were categorized as C (n=64) or ER (n=42) using a composite-score of early alcohol/drug use and problems based on prospectively collected assessments; externalizing behaviors were also previously assessed during adolescence. Neuroanatomical volumes were compared between groups and correlated with behavioral measures.

RESULTS

ER subjects exhibited more externalizing behaviors than their control counterparts. Total left frontal cortex and left superior frontal cortex volumes were significantly smaller in the ER group, controlling for family history of alcoholism and current substance use. Total gray matter volumes were negatively associated with substance risk score. Further, externalizing behavior score was negatively correlated with both left superior cortical and left total cortical volumes.

CONCLUSIONS

These findings suggest that smaller frontal cortical volumes, specifically the left superior frontal cortex, represent an underlying risk factor for substance abuse in emerging adults.