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. Author manuscript; available in PMC: 2017 May 1.
Published in final edited form as: Curr Psychiatry Rep. 2016 May;18(5):46. doi: 10.1007/s11920-016-0689-y

Table 1.

Summary of pre- and post-substance use initiation on adolescent brain development

Pre-existing neural features relating to ↑ substance use during adolescence Effects of alcohol and marijuana on neural development
Neuropsychological testing

  • ↓ Inhibitory functioning

  • ↓ Working memory

 Alcohol:

  • ↓ Verbal learning and memory

  • ↓ Visuospatial functioning

  • ↓ Psychomotor speed

  • ↓ Working memory

Marijuana:

  • ↓ Attention

  • ↓ Memory

  • ↓ Processing speed

  • ↓ Visuospatial functioning

  • ↓ Cognitive control

  • ↓ IQ
Brain structure

  • ↓ Frontal, nucleus accumbens, anterior cingulate, and cerebellar white matter volume

  • ↓ White matter integrity in fronto-limbic tracts

 Alcohol:

  • ↓ Accelerated decreases in gray matter (frontal, temporal)

  • ↓ Attenuated white matter development (pons, corpus callosum)

  • ↓ White matter integrity

Marijuana:

  • ↑ Cortical thickness (frontal, parietal)

  • ↓ White matter integrity
Brain functioning

  • ↓ Brain activation during tasks of inhibition and working memory

  • ↑ Reward response in frontal regions

Aberrant resting state functional connectivity		 Alcohol:

  • ↑ Brain activation during inhibition and working memory