Is the Mini-Mental State Examination (MMSE) useful for eligibility screening of research participants with substance use disorder?

Abstract

Introduction: the MMSE is used for eligibility screening of potential research participants diagnosed with substance use disorder (SUD), as abilities needed to provide a valid informed consent or accurate information could be impaired in these clinical populations. Knowledge about the capacity of the MMSE to detect impairment in these abilities or at least to assess impact of SUD on its total score, however, is rather diffuse. This has important ethical and methodological implications. Objective: to analyze effects of SUD only, main substances of abuse, age of onset of substance use, recent substance use, and psychiatric comorbidity upon MMSE outcome. The overall purpose of the study was to assess the utility of the MMSE for eligibility screening of potential research participants with SUD. Method: individuals were recruited from residential facilities for substance use treatment. A demographic questionnaire, MMSE and Mini International Neuropsychiatric Interview were used. Results: A total of 601 participants were gathered for main analysis. Controlling for education, no differences in MMSE score were detected within main substances of abuse (F=1.25[4,529], p=.28), nor between SUD only versus SUD with psychiatric comorbidity (F=.58[1,597], p=.44). Effects of age of onset and recent use of specific substances upon MMSE score were also absent. Discussion and conclusions: If there is some cognitive impairment in this clinical population, it may not be pertinently assessed by the MMSE, thus casting doubt on its pertinence for eligibility screening.