Gray matter volume differences in impulse control and addictive disorders (2020)

March 2020

BACKGROUNDS: The concepts of addictions and impulse control disorders are changing as reflected in the 11th version of International Classification of Disorders (ICD-11, WHO, 2018). However, studies focusing on direct comparison of structural brain differences in behavioral and substance addictions are limited.

AIM: Here we contrast gray matter volumes (GMVs) across groups of individuals with compulsive sexual behavior disorder (CSBD), gambling disorder (GD), and alcohol use disorder (AUD) with those with none of these disorders (healthy controls participants; HCs).

METHODS: Voxel-based morphometry (VBM) was employed to study brain structure and severities of addictions symptoms were assessed with questionnaires. To identify brain regions related to severities of addictions, correlations between questionnaires scores and GMVs were computed.

MAIN OUTCOME: We collected MRI (GMVs) data from 26 CSBD patients, 26 GD patients, 21 AUD patients and25 HC participants (all heterosexual males; age: 24-60; M = 34.5, SD = 6.48).

RESULTS: Affected individuals (CSBD, GD, AUD) compared to HC participants showed smaller GMVs in the left frontal pole, specifically in the orbitofrontal cortex. The most pronounced differences were observed in the GD and AUD groups, and the least in the CSBD group. There was a negative correlation between GMVs and disorder severity in the CSBD group. Higher severity of CSBD symptoms was correlated with decreased GMV in the right anterior cingulate gyrus.

CLINICAL IMPLICATIONS: Our findings suggest similarities between specific impulse control disorders and addictions.

STRENGTHS AND LIMITATIONS: This study is the first showing smaller GMVs in 3 clinical groups of CSBD, GD and AUD. But the study was limited only to heterosexual men. Longitudinal studies should examine the extent to which ventral prefrontal decrements in volume may represent preexisting vulnerability factors or whether they may develop with disorder progression.

CONCLUSIONS: Our research extends prior findings in substance use disorders of lower GMV in prefrontal cortical volumes among 3 clinical groups of patients with specific impulse control and behavioral and substance addictive disorders. The negative correlation between GMVs and CSBD symptoms and right anterior cingulate gyrus suggests a link with clinical symptomatology.