High resolution brain SPECT imaging of marijuana smokers with AD/HD

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Marijuana abuse is prevalent among young Americans, especially those with attention deficit/hyperactivity disorder (AD/HD).
• Many young individuals perceive marijuana as safe, despite evidence of cognitive impairment from chronic use.
• Brain SPECT imaging is increasingly utilized in psychiatry to investigate functional brain abnormalities, including those in AD/HD.

Purpose of the Study:

• To investigate the effects of chronic heavy marijuana use on cerebral blood flow in adults with AD/HD using SPECT imaging.
• To compare brain perfusion patterns between heavy marijuana users with AD/HD and a control group of AD/HD individuals without drug history.

Main Methods:

• Brain SPECT imaging was conducted on 30 heavy marijuana users (weekly use for ≥1 year) with AD/HD and 10 AD/HD controls (no drug history).
• Subjects were matched for age and sex.
• Three-dimensional surface images were analyzed by blinded interpreters unaware of the clinical data.

Main Results:

• Both groups showed decreased prefrontal cortex perfusion during a concentration task.
• The marijuana group exhibited significant decreases in activity in the right and left temporal lobes.
• Severe and moderate perfusion decreases were associated with heavier, not necessarily longer-term, marijuana use.

Conclusions:

• Chronic marijuana use is associated with decreased cerebral perfusion in the temporal lobes, observable via SPECT imaging.
• Findings suggest potential neurobiological alterations in heavy marijuana users with AD/HD.
• The study highlights the need for greater awareness regarding the risks of marijuana use in vulnerable populations.