Delayed preattentional functioning in early psychosis patients with cannabis use

Nicole Pesa, Daniel F. Hermens, Robert A. Battisti, Manreena Kaur, Ian B. Hickie, Nadia Solowij

Research output: Contribution to journalArticleResearchpeer-review

18 Citations (Scopus)


Rationale: Cannabis use is prevalent among the early psychosis (EP) population. The event-related potentials, mismatch negativity (MMN) and P3a are reduced in EP. Cannabinoids have been shown to modulate N-methyl-Daspartate receptors which are involved in MMN generation. 

Objectives: This study is the first to investigate the effects of cannabis use on MMN/P3a in EP. 

Methods: EP was defined as a history of psychosis or psychotic symptoms with no progression to date to chronic schizophrenia. Twenty-two EP patients with cannabis use (EP+CANN), 22 non-cannabis-using EP patients (EPCANN) and 21 healthy controls participated in this study. MMN/P3a was elicited using a two-tone, auditory paradigm with 8% duration deviants. 

Results: As expected, EP-CANN showed marked reductions in MMN/P3a amplitudes compared to controls. However, EP+CANN showed evidence of a different pattern of neurophysiological expression of MMN/P3a compared to nonusing patients, most notably in terms of delayed frontal MMN/P3a latencies. 

Conclusions: This study provides further evidence that MMN/P3a deficits are present during early psychosis and suggests that this biomarker may have utility in differentiating substance- from non-substance-related psychoses.

Original languageEnglish
Pages (from-to)507-518
Number of pages12
Issue number3
Publication statusPublished - Aug 2012
Externally publishedYes


  • Cannabis
  • Marijuana
  • Mismatch negativity
  • MMN
  • P3a
  • Psychosis

Cite this