Multiple sclerosis and cannabis: a cognitive and psychiatric study.

Area of Science:

• Neurology
• Psychiatry
• Neuroscience

Background:

• A notable portion of multiple sclerosis (MS) patients use cannabis.
• Previous research has not investigated cannabis's effects on mentation in MS.
• This study examines the emotional and cognitive associations of cannabis use in MS patients.

Purpose of the Study:

• To investigate the emotional and cognitive effects of street cannabis use in patients diagnosed with multiple sclerosis.
• To determine if cannabis use is associated with psychiatric diagnoses in MS patients.
• To assess the impact of cannabis on cognitive functions, including information processing speed, working memory, and sustained attention.

Main Methods:

• 140 consecutive MS patients were interviewed using the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-IV) to record cannabis use details.
• Cognitive function was evaluated using the Neuropsychological Battery for MS and the Symbol Digit Modalities Test (SDMT).
• Current cannabis users (n=10) were matched with non-users (n=40) based on demographic and disease variables for comparison.

Main Results:

• Current cannabis users (7.7%) were younger than non-users.
• A higher proportion of cannabis users met DSM-IV criteria for psychiatric diagnoses compared to non-users (p=0.04).
• Cannabis users exhibited slower performance on the SDMT (p=0.006) and a different response pattern, indicating impaired information processing speed, working memory, and sustained attention.

Conclusions:

• Inhaled cannabis use is associated with impaired mentation, particularly cognitive deficits, in multiple sclerosis patients.
• The findings suggest a potential negative relationship between cannabis use and cognitive health in MS.
• Further research is needed to establish the causal direction of this association.