Brain Cortical Thickness Differences in Adolescent Females with Substance Use Disorders

Abstract

Methods: We recruited right-handed female patients, 14-19 years of age, from a university-based treatment program for youths with substance use disorders and community controls similar for age, race and zip code of residence. We obtained 43 T1-weighted structural brain images (22 patients and 21 controls) to examine group differences in cortical thickness across the entire brain as well as six a priori regions-of-interest: 1) medial orbitofrontal cortex; 2) rostral anterior cingulate cortex; and 3) middle frontal cortex, in each hemisphere. Age and IQ were entered as nuisance factors for all analyses.

Results: A priori region-of-interest analyses yielded no significant differences. However, whole-brain group comparisons revealed that the left pregenual rostral anterior cingulate cortex extending into the left medial orbitofrontal region (355.84 mm2 in size), a subset of two of our a priori regions-of-interest, was significantly thinner in patients compared to controls (vertex-level threshold p = 0.005 and cluster-level family wise error corrected threshold p = 0.05). The whole-brain group differences did not survive after adjusting for depression or externalizing scores. Whole-brain within-patient analyses demonstrated a positive association between cortical thickness in the left precuneus and behavioral disinhibition scores (458.23 mm2 in size).

Conclusions: Adolescent females with substance use disorders have significant differences in brain cortical thickness in regions engaged by the default mode network and that have been associated with problems of emotional dysregulation, inhibition, and behavioral control in past studies.

Fig 1. Whole-brain analyses testing for female patient-control differences in cortical thickness in QDEC using a vertex-level threshold of p<0.005 and Monte-Carlo simulation generated cluster level threshold.

Medial view of left hemisphere here shows control>patient differences in cortical thickness of the pregenual rostral anterior cingulate cortex extending to the medial orbitofrontal cortex.

Fig 2. Whole-brain regression analyses within the patient group for correlation between cortical thickness and BD severity in QDEC (see Methods, Data Analyses and Discussion, ROI vs. Whole Brain Results for explanation of BD scores).

Medial view of left hemisphere here shows positive correlation between BD scores and cortical thickness of the precuneus.