Preserved reading and spelling ability in psychotic disorders.

Standard scores on tests of intelligence, memory and academic achievement were obtained from individuals with either schizophrenic spectrum disorders, mania, alcohol abuse, antisocial personality disorders or no mental disorder. The three cognitive measures were highly and positively correlated in three groups (normal controls, alcohol abusers and antisocial personality disorders), while in the schizophrenic spectrum and manic groups a pattern of average reading and spelling achievement was contrasted with lower intelligence and memory quotients. It was suggested that reading and spelling ability are more accurate predictors of premorbid ability in psychotic disorders than other psychometric scales. This parallels previous findings with organic dementias and raises questions about possible shared aetiological bases between dementias and psychoses.