There is growing evidence suggesting that
adolescence is a key period for neuronal maturation. The
results of the current study support that heavy cannabis
use during adolescence is related to brain damage in areas
known to be involved in ongoing development during late
adolescence, particularly in the fronto-temporal connection
via arcuate fasciculus. These results suggest that earlyonset
substance use may affect the development of fronto-
temporal white matter circuits, potentially resulting in
disturbed memory, and deficits in executive and affective
functioning (Lubman et al., 2007). Since five of the HCU
subjects were alcohol abusers, conclusions from our report
should be considered preliminary as the DTI findings
reported here may be due to combination of alcohol and
marijuana use. Adolescence, however, being marked as a
critical time for brain maturation and development, may
be a vulnerable period to partake in risky behaviors, such
as marijuana or alcohol use, for both physiological

Source: extract from  Journal of Psychiatric Research 43 (2009) 189–204