<prompt> A PATIENT OF SCHIZOPHRENIA TREATED FOR 5 YEARS DEVELOPE PERIORAL MOVEMENTS. LIKELY DIAGNOSIS IS:Tardive dyskinesiaMuscular dystoniaAkathisiaMalignant neuroleptic syndrome  <response>: TARDIVE DYSKINESIA IS THE MOST COMMON DELAYED LATE COMPLICATION OF ANTIPSYCHOTIC MEDICATION IT IS CHARACTERISED BY PURPOSELESS, INVOLUNTARY FACIAL AND LIMB MOVEMENTS TARDIVE DYSKENYSIS MUSCULAR DYSTONIA : - IS CHARACTERISED BY BIZZARE MUSCLE SPASMS SPECIALLY AFFECTING LINGUOFASCIAL MUSCLES - GRIMACING ETC.OCCURS WITHIN FEW HOURS OF A SINGLE DOSE AT MOST MOST WITHIN A WEEK. MUSCULAR DYSTONIA THUS W HILE FACIAL MOVEMENTS CAN BE A FEATURE OF BOTH TARDIVE DYSKINESIA AND MUSCULAR DYSTONIA, THOSE DEVELOPING AS LATE AS 5 YEARS AFTER ITUTION OF TREATMENT ARE LIKELY TO BE DUE TO BE DUE TO TARDIVE DYSKINESIA. AKATHASIA : REFERS TO REST LESSNESS F EELING OF DISCOMFO APPARENT AGITATION FACIAL MOVEMENTS ARE NOT A FEATURE. AKATHASIA MALIGNANT NEUROLEPTIC SYNDROME : IS CHARACTRISED BY RIGIDITY, IMMOBILITY, FEVER, FLUCTUATING BP AND HEA RATE. FACIAL MOVEMENTS ARE NOT A FEATURE REF : HARRISONS 20TH ED 