Different biogenetic causal explanations and attitudes towards persons with major depression, schizophrenia and alcohol dependence: is the concept of a chemical imbalance beneficial?

OBJECTIVE: It is unclear whether different biogenetic causal beliefs affect stigmatization of mentally-ill patients differently. It has been argued that in particular believing in a 'chemical imbalance' as a cause of mental disorder might be associated with more tolerant attitudes.
METHOD: In a representative population survey in Germany (n=3642), using unlabelled case vignettes of persons with depression, schizophrenia, or alcohol dependence, we elicited agreement with three different biogenetic explanations of the illness: 'Chemical imbalance of the brain', 'brain disease' and 'heredity'. We further investigated emotional reactions as well as the desire for social distance. For each vignette condition we calculated linear regressions with each biogenetic explanation as independent and emotional reactions as well as social distance as dependent variable controlling for socio-demographic variables. LIMITATIONS: Our cross-sectional study does not allow statements regarding causality and the explanatory power of our statistical models was low.
RESULTS: 'Chemical imbalance of the brain' and 'brain disease' were both associated with a stronger desire for social distance in schizophrenia and depression, and with more social acceptance in alcohol dependence, whereas 'heredity' was not significantly associated with social distance in any of the investigated illnesses. All three biogenetic causal beliefs were associated with more fear in all three illnesses.
CONCLUSION: Our study corroborates findings that biogenetic explanations have different effects in different disorders, and seem to be harmful in depression and schizophrenia. A particular de-stigmatizing potential of the causal belief 'chemical imbalance' could not be found. Implications for useful anti-stigma messages are discussed.