Background 
Marijuana and khat, as commonly called cannabis and cathine respectively are widely used in Ethiopia. However, there are very limited and conflicting data about their effects on memory of patients with vascular dementia. Besides it is not clear if these recreational addictive substances have improving or worsening impacts on these patients.
Objective 
Assess impacts of Cannabis and Cathine on memory among patients with vascular dementia.
Methods 
We reviewed medical records of 300 patients with vascular dementia in Black Lion Hospital from January 2010 to December 2017 and identified 4 groups (Cannabis and Khat users, Cannabis only, Khat only and non-users) and compared their memory using Montreal cognitive assessment test score done at the beginning and their follow-up visits.
Results
Baseline characteristics, including risk factors for stroke were all comparable except for gender where 216(90%) were male substance abusers.120 (40%) patients use Cannabis and Cathine. 54 (18%) use cannabis only and 66 (22%) use Cathine only. For age, education level matched analysis, baseline and 2 follow up Montreal cognitive assessment test scores demonstrated sharp decline in memory function in patients who abuse cannabis and Khat (OD of 2.31, 95% CI 1.61 - 2.45), moderate decrement in Cannabis users (OD of 1.24, 95% CI 0.93 - 1.45) and no significant change noticed among khat users (OD of 0.86, 95% CI 0.83 - 1.12).
CONCLUSION 
Cannabis plays a major role in deterioration of memory, especially if taken together with Khat among patients with vascular dementia while khat alone has no effect on memory.

RETROSPECTIVE STUDY ON EFFECTS OF MARIJUANA AND KHAT ON MEMORY AMONG VASCULAR DEMENTIA PATIENTS