The major difference between typical and atypical antipsychotics is that

The most impoant reason to classify the antipsychotics in typical and atypical agents is the occurrence of extrapyramidal symptoms. Typical antipsychotics have significant extrapyramidal symptoms such as parkinsonism, acute muscle dystonia and tardive dyskinesia. These side-effects are negligible or minimal with atypical agents like clozapine, olanzapine and risperidone.