Why Teens Started Using Cannabis Predicted Their Schizophrenia Risk and Severity

The reasons adolescents gave for starting cannabis use - sedation, stimulation, social pressure, or recreation - predicted both their risk of developing schizophrenia-spectrum disorder and the severity of their symptoms.

Shahzade, C et al.·Schizophrenia research·2018·Moderate EvidenceCross-Sectional
RTHC-01834Cross SectionalModerate Evidence2018RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Moderate Evidence
Sample
N=178

What This Study Found

Factor analysis of cannabis use motives produced four groups (sedation, stimulation, social pressure, recreation). These motive factor scores significantly predicted schizophrenia-spectrum disorder risk and schizotypal symptom severity. The factors followed a hierarchical structure explaining their relative involvement in SSD risk.

Key Numbers

178 participants total: healthy controls with cannabis use and schizophrenia patients with cannabis use. Four motive factors identified: sedation, stimulation, social pressure, and recreation.

How They Did This

178 participants in two samples: healthy controls with cannabis use and schizophrenia patients with cannabis use. Structured interviews with participants and family informants assessed diagnostic information, cannabis use motives, and clinical measures.

Why This Research Matters

If the reasons for starting cannabis use can predict psychosis risk, this offers a potential screening tool. Rather than simply asking "do you use cannabis," clinicians could assess why someone uses to better identify who is at highest risk.

The Bigger Picture

This study suggests that not all adolescent cannabis use carries the same risk. The motivation behind use may reflect underlying neurobiological differences that predispose certain individuals to psychosis, offering a more nuanced view than "cannabis causes schizophrenia."

What This Study Doesn't Tell Us

Cross-sectional design limits causal conclusions. Retrospective recall of motives may be inaccurate. No assessment of cannabis potency, frequency, or duration. Relatively small sample for factor analysis.

Questions This Raises

  • ?Do certain motives for cannabis use reflect pre-existing neurobiological vulnerability?
  • ?Could motive-based screening identify at-risk individuals before psychosis onset?
  • ?Would the same motive patterns predict risk in larger, prospective studies?

Trust & Context

Key Stat:
Four distinct motives for adolescent cannabis use (sedation, stimulation, social pressure, recreation) formed a hierarchical structure predicting schizophrenia risk.
Evidence Grade:
Moderate - novel finding with appropriate statistical methods, but cross-sectional with retrospective motive reporting.
Study Age:
Published in 2018.
Original Title:
Patterns in adolescent cannabis use predict the onset and symptom structure of schizophrenia-spectrum disorder.
Published In:
Schizophrenia research, 197, 539-543 (2018)
Database ID:
RTHC-01834

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

Does it matter why teens start using cannabis?

This study found that the reasons for starting cannabis use - whether for sedation, stimulation, social pressure, or recreation - predicted schizophrenia risk and symptom severity. This suggests not all cannabis use carries the same risk.

Can you predict who will develop psychosis from cannabis use?

This study found that motives for initiating cannabis use in adolescence predicted both schizophrenia risk and symptom severity. The researchers propose this could form the basis of a screening model for at-risk individuals.

Read More on RethinkTHC

Cite This Study

RTHC-01834·https://rethinkthc.com/research/RTHC-01834

APA

Shahzade, C; Chun, J; DeLisi, L E; Manschreck, T C. (2018). Patterns in adolescent cannabis use predict the onset and symptom structure of schizophrenia-spectrum disorder.. Schizophrenia research, 197, 539-543. https://doi.org/10.1016/j.schres.2018.01.008

MLA

Shahzade, C, et al. "Patterns in adolescent cannabis use predict the onset and symptom structure of schizophrenia-spectrum disorder.." Schizophrenia research, 2018. https://doi.org/10.1016/j.schres.2018.01.008

RethinkTHC

RethinkTHC Research Database. "Patterns in adolescent cannabis use predict the onset and sy..." RTHC-01834. Retrieved from https://rethinkthc.com/research/shahzade-2018-patterns-in-adolescent-cannabis

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.