The Impact of Polysubstance Use and Substance Abuse on Cognitive and Clinical Measures in Individuals on the Psychosis Spectrum

Marlynn Lopez, BS

Beth Israel Deaconess Medical Center – Research Assistant

Scientific Abstract


Individuals with a psychosis spectrum disorder are at a significantly higher risk of abusing substances and polysubstance use (~50%). Additionally, polysubstance abuse has been linked to worsening positive symptoms. However, literature pertaining to the severity of substance use on cognition in psychosis are mixed. Here, we aimed to investigate the effects of polysubstance use and frequency of substance use on cognition in individuals with psychosis.


Clinical and cognitive performance were measured by the Positive and Negative Syndrome Scale (PANSS), Montgomery-Asperg Depression Rating Scale (MADRS), Young Mania Rating Scale (YMRS) and Brief Assessment of Cognition in Schizophrenia (BACS) in a cohort of 744 individuals with idiopathic psychosis. Substance use and frequency were quantified through standard clinical interviews. Three groups (200 = high, 426 = mid, 193 = low) were derived using a composite score reflecting frequency of lifetime use in 7 different categories of drugs: cannabis, stimulants, cocaine, alcohol, hallucinogens, opioids, and other substances. Group comparisons were performed and an FDR threshold of p<0.10 was set.


The group with the highest severity of substance use performed better all cognitive domains for the BACS, when compared to moderate and low users (p < 0.001). Individuals with the lowest substance use had the poorest cognitive performance in comparison to the other groups (p < 0.001). High and moderate substance users had significantly elevated levels of manic symptoms in comparison to low substance users (p <0.08). In accordance with the literature, positive symptoms were worse for high substance users when compared to low users (p < 0.09).


Our findings suggest that cognitive changes due to severity of polysubstance use could be independent from cognitive impairments seen in individuals with psychosis. Specifically, greater severity of substance use did not worsen cognitive ability but rather was associated with increased cognitive performance. This indicates the potential of employing severity of substance use as a parameter for forming a subgroup of individuals on the psychosis spectrum.

Live Zoom Session – March 9th

research Areas


Marlynn Lopez, BS, Nicolas Raymond, BA, Sarah Keedy, PhD, Scott K. Hill, PhD, Godfrey D. Pearlson, MD, Jeffrey Bishop, MS, BCPP, FCCP, Carol A. Tamminga, MD, John Sweeney, PhD, Elliot S. Gershon, MD, Brett Clementz, PhD, Matcheri Keshavan, MD, Paulo Lizano, MD, PhD

Principal Investigator

Paulo Lizano, MD, PhD