Akathisia is a syndrome of motor restlessness, principally seen in association with antipsychotic medication. It is characterized by a subjective experience of mental unease and the urge to move, and manifests physically as particular patterns of restless movement. This review focuses on the signs and symptoms of the condition, and its diagnosis and assessment using the Barnes Akathisia Rating Scale. This scale was generated 15 years ago, and was derived from the findings of studies exploring the clinical features of antipsychotic-induced akathisia. Subsequently, its validity and reliability have been established, and it has been used extensively in clinical studies worldwide.