Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (2 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2007)

Background: Depressed mood has been associated with decreased white matter and reduced hippocampal volumes. However, the relationship between brain structure and mood may be unique among adolescents who use marijuana heavily. The goal of this study was to examine the relationship between white matter and hippocampal volumes and depressive symptoms among adolescent marijuana users and controls. Methods: Data were collected from marijuana users (n = 16) and demographically similar controls (n = 16) aged 16-18. Extensive exclusionary criteria included psychiatric and neurologic disorders, including major depression. Substance use, mood, and anatomical measures were collected after 28 days of monitored abstinence. Results: Marijuana (MJ) users demonstrated more depressive symptoms than controls (p < .05). MJ use (beta = .42, p < .005) and smaller white matter volume (beta = -.34, p < .03) each predicted higher levels of depressive symptoms on the Hamilton Depression Rating Scale. MJ use interacted with white matter volume (beta = -.55, p < .03) in predicting depression scores on the Beck Depression Inventory: among MJ users, but not controls, white matter volume was negatively associated with depressive symptoms. Conclusions: Marijuana use and white matter volume were additive and interactive in predicting depressive symptoms among adolescents. Subtle neurodevelopmental white matter abnormalities may disrupt the connections between areas involved in mood regulation.

    Cover page: Depressive symptoms in adolescents: associations with white matter volume and marijuana use
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2015)

    Background

    Amygdala volume abnormalities have been reported in relation to craving in substance-dependent adults, but it remains unclear if these effects are seen in adolescent marijuana (MJ) users, particularly following abstinence.

    Objectives

    The aim of this study was to examine the relationship between amygdala volume and craving during 28 days of abstinence in adolescent MJ users.

    Methods

    MJ-using adolescents (n = 22) aged 16-19 were recruited as part of a larger study on brain function in teen drug users. Craving measures were collected twice per week throughout a 28-day abstinence period. High-resolution anatomical magnetic resonance imaging data were collected at the end of the 28 days of confirmed abstinence. Left and right amygdala volumes were traced by hand (ICC > 0.86). Composite scores for self-reported craving and withdrawal symptoms throughout the 28-day abstinence period were calculated to provide four composite measures of total craving, mood, sleep, and somatic complaints.

    Results

    Results revealed that greater craving during abstinence was significantly associated with smaller left and right amygdala volumes, after controlling for age and gender. Other measures of withdrawal, including mood, somatic complaints and sleep problems, were not related to amygdala morphometry.

    Conclusion

    These results are consistent with previous findings in adult alcohol- and cocaine-dependent individuals, who demonstrated a relationship between reduced amygdala volumes and increased craving. Future studies are needed to determine if these brain-behavior relationships are attributable to MJ use or predate the onset of substance use.
      Top