Is there a burden attached to synaesthesia? Health screening of synaesthetes in the general population.
Level 4 - case-series / case-control
Cross-sectional case-control screening studies
PubMed 30281144 · doi:10.1111/bjop.12354
What was done
Two cross-sectional screening cohorts assessed the prevalence of clinical health conditions among objectively identified grapheme-colour synaesthetes compared to non-synaesthete controls. Study 1 screened 3,742 individuals (95 synaesthetes and 3,647 controls). Study 2 evaluated an independent cohort of 286 individuals (120 synaesthetes and 166 non-synaesthetes) while addressing a methodological concern from the first study.
What was found
Study 1 found that grapheme-colour synaesthesia was significantly comorbid with anxiety disorder and obsessive-compulsive disorder. Study 2 replicated the significant comorbidity with anxiety disorder, while addressing methodological issues that likely elevated rates of obsessive-compulsive disorder in Study 1. The abstract reports no numerical prevalence rates, odds ratios, p-values, or confidence intervals.
Why it matters
This study provides population-level evidence challenging the notion that synaesthesia is strictly benign, demonstrating a replicated link between grapheme-colour synaesthesia and anxiety disorder that suggests potential shared genetic or neurological mechanisms.
Limits
No exact numbers, odds ratios, or significance values are provided in the abstract. Clinical conditions were assessed via participant-elicited screening rather than in-person clinical diagnostic interviews, the cross-sectional design cannot establish causality, and findings are restricted to grapheme-colour synaesthesia.
Cited by
- supports At least 3% of the human population has synesthesia.