it's not about a mental illness. deductive reasoning is a natural, largely untrainable, cognative mesurement like iq. you either have it or you don't. for some reason, it's mostly not tested for in iq tests (which focus on inductive reasoning primarily). many high iq indivduals may have an average logical deduction ability, which in turn renders you less capable than someone with a very high deductive ability. as i stated before a upper-average midwit who scores highly on a deductive reasoning test will likely outperform a 140+ iq individual who scores average deductive reasoning test in the majority of fields, save for high level abstract professions.
United Kingdom