We were looking for factors which corresponded to the overall rise in homicides in people with psychosis; factors which showed increases of a similar magnitude, over a similar timescale. This was the case for drug misuse, allowing us to infer an association. Evidence has been found linking income inequality to both violent crime ^{Reference Wilkinson1} and rates of substance misuse, ^{Reference Wilkinson and Picket2} although this has been disputed and there is controversy ^{Reference Pickett, James and Wilkinson3} over the validity of the association found between income inequality and mental illness. ^{Reference Huisman and Avendano4} There has been a marked increase in income inequality in recent years ^{Reference Davey Smith, Dorling, Mitchell and Shaw5} but, from the data which we have available to us, we are unable to comment as to whether this is also the case among those with mental illness, and whether there is any causal association with homicide rates. In future research we hope to explore the data using deprivation indices which might provide further information on any association between income inequality, mental illness and homicide.