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Causality assessment · Causality: well established

Quetiapine (antipsychotics) and Diabetes mellitus: is the FAERS signal real?

n=8,357 co-reports · PRR 13.3 · ROR 13.9
Quetiapine (antipsychotics) side-effect profileAll assessmentsSee in the full list
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Causality: well established

Quetiapine (antipsychotics) ↔ Diabetes mellitus

n=8,357 co-reports · PRR 13.3 · ROR 13.9

Reporting over time (stimulated-reporting check)

2004: 1 reports (1.82% of the drug's reports)2005: 7 reports (1.58% of the drug's reports)2006: 38 reports (9.13% of the drug's reports)2007: 65 reports (15.01% of the drug's reports)2008: 1 reports (0.18% of the drug's reports)2009: 4 reports (0.70% of the drug's reports)2010: 3 reports (2.03% of the drug's reports)2011: 5 reports (2.34% of the drug's reports)2012: 3 reports (0.49% of the drug's reports)2013: 0 reports (0.00% of the drug's reports)2014: 1 reports (0.21% of the drug's reports)2015: 5 reports (0.77% of the drug's reports)2016: 3 reports (0.38% of the drug's reports)2017: 2 reports (0.18% of the drug's reports)2018: 6 reports (0.35% of the drug's reports)2019: 10 reports (0.46% of the drug's reports)2020: 16 reports (0.76% of the drug's reports)2021: 18 reports (0.65% of the drug's reports)2022: 29 reports (0.98% of the drug's reports)2023: 17 reports (0.67% of the drug's reports)2024: 19 reports (0.58% of the drug's reports)2025: 17 reports (0.50% of the drug's reports)05081114172023

Reporting spiked in 2007 — 38% of all 270 reports arrived in two years (2006–2007). A burst like this usually follows a regulatory communication, media coverage or litigation advertising rather than a change in the drug's effect; it inflates disproportionality for those years.

Bars: reports per year as a share of all FAERS reports for this drug, 2004–2025; amber = spike year (>3× the median share, ≥50 reports). Source: openFDA count=receivedate, retrieved 2026-10-09.

Quetiapine is a second-generation antipsychotic, and weight gain, dyslipidaemia, and hyperglycaemia/diabetes are its best-known metabolic effects — shared across the class but differing in magnitude by molecule. The FDA required a class warning about hyperglycaemia and diabetes for all atypical antipsychotics in 2003. The mechanism (weight gain, insulin resistance, and possibly direct effects on glucose regulation) is well described, and the effect is dose- and duration-related and largely manageable with baseline and periodic metabolic monitoring.

Regulatory basis: FDA class warning on hyperglycemia and diabetes with atypical antipsychotics (2003); quetiapine prescribing information (metabolic monitoring).

Bradford Hill viewpointStatusNote
Temporality (necessary)partialMetabolic changes emerge over weeks–months of treatment
StrengthpartialPRR 13 — modest, and confounded by the population's baseline risk
ConsistencymetA consistent class effect across atypical antipsychotics
SpecificitypartialClass-wide, with real differences in magnitude between agents
Biological gradientmetTracks with dose and the degree of weight gain
PlausibilitymetWeight gain and insulin resistance are named, established mechanisms
CoherencemetCoheres with the class's documented metabolic syndrome risk
ExperimentpartialImprovement on switching/withdrawal is supportive, not a randomized test
AnalogymetShared with other second-generation antipsychotics

This page's own qualitative read, not an automated/citation-gated assessment.

✗ Searched; the trial that surfaced cannot characterize the risk. In a quetiapine-XR vs risperidone trial (NCT00600756), diabetes was recorded as a serious event in 0/391 on quetiapine XR and 1/402 on risperidone — far too few events, over too short a period, to measure a metabolic risk. The class warning rests on longer-term data.