Do Substance-Induced Psychoses Impair Cognitive Abilities as Much as Schizophrenia?

Worldwide, over 296 million people used drugs in 2021, marking a 23% increase over a decade. Among them, a growing number are developing psychotic disorders directly linked to this use. These psychoses, often triggered by cannabis, amphetamines, or polysubstance abuse, raise a critical question: Are their effects on intellectual abilities comparable to those observed in schizophrenia?

A comprehensive analysis of 18 studies involving 1,092 patients reveals that cognitive impairments in individuals with substance-induced psychoses are broadly similar to those in schizophrenic patients. Both groups exhibit comparable difficulties in memory, attention, psychomotor speed, and intellectual functioning. Only executive functions—which enable planning, organizing, and regulating actions—show a slight difference. Individuals with substance-induced psychoses appear to be somewhat less affected in this area than those with schizophrenia.

These findings underscore the severity of the consequences of substance use on the brain. Drug-induced psychoses are not benign episodes: they can lead to lasting cognitive impairments, comparable to those of a major psychiatric illness like schizophrenia. This similarity is partly explained by shared brain alterations observed in both types of patients.

Distinguishing between these two disorders remains a challenge for healthcare professionals. Misidentification can lead to inappropriate treatments, such as prolonged antipsychotic prescriptions for patients whose psychosis is substance-related. Conversely, targeted management focusing on substance cessation and gradual medication reduction may be more suitable for these individuals.

This study highlights the urgency of better understanding and treating substance-induced psychoses. It also serves as a reminder that drug use, even occasional, can have serious and lasting repercussions on the brain.

Information and Sources

Scientific Reference

DOI: https://doi.org/10.1007/s11065-025-09687-1

Title: Substance-induced Psychotic Disorders Cause Convergent Cognitive Impairment to Schizophrenia Spectrum Disorders: A meta-analysis of Comparative Studies

Journal: Neuropsychology Review

Publisher: Springer Science and Business Media LLC

Authors: Irena Semancikova; Filip Dechterenko; Pooja Patel; Ondrej Bezdicek