Neurofunctional changes in adolescent cannabis users with and without bipolar disorder

Area of Science:

• Neuroscience
• Psychiatry
• Addiction Medicine

Background:

• Bipolar disorder (BP) and cannabis use disorder (C-UD) are prevalent in adolescents.
• Co-occurrence of BP and C-UD may impact neurobiological pathways.
• Understanding regional brain activation differences is crucial for targeted interventions.

Purpose of the Study:

• To compare regional brain activation patterns between adolescents with BP, C-UD, co-occurring BP and C-UD (BPMJ), and healthy controls (HC).
• To investigate the neural correlates of emotional processing and cannabis cue reactivity in these groups.

Main Methods:

• Cross-sectional study involving four groups: BP (n=14), C-UD (n=13), BPMJ (n=25), and HC (n=15).
• Functional magnetic resonance imaging (fMRI) was used to assess Blood Oxygenation Level Dependent (BOLD) signal during a cannabis cue-reactivity task.
• Standardized questionnaires assessed cannabis craving (MCQ) and substance use severity (T-ASI).

Main Results:

• The BP group showed significantly greater activation in the right amygdala, left nucleus accumbens, and bilateral thalamus compared to the BPMJ group.
• Adolescents with BP also exhibited greater activation in the left nucleus accumbens, right thalamus, and left striatum compared to HC.
• Left amygdala activation in the BPMJ group trended towards a negative correlation with the number of joints smoked.

Conclusions:

• Adolescents with co-occurring BP and C-UD do not display the same heightened activation in emotional processing regions as those with BP alone.
• This suggests a potentially unique endophenotype in adolescents with comorbid BP and C-UD.
• Cannabis use may uniquely modulate brain activation in adolescents diagnosed with bipolar disorder.