The core symptoms of Autistic Spectrum Disorder (ASD) are impairment in reciprocal social interaction, communication, narrow interests, and stereotyped behaviour. These are frequently severe and persistent, although their severity may change over the course of life. Furthermore, the frequently associated symptoms of self-injury, aggressive behaviour, impulsivity, poor attention, anxiety, depression, and sleep disruption, can become a major source of additional distress and interference in functioning. The causes of autism are not yet known, but there is a general consensus that ASDs are highly heritable. Comprehension of the neurobiological basis for autism-spectrum disorders is still in its initial stages: a large body of research, however, has established ASD signs and symptoms are of neurological origin, and suggest that autism is a distributed neural system disorder, which disproportionately impairs many higher order abilities. Currently available medical treatments, primarily address co-morbid symptoms, rather than core symptoms. Thus, in spite of recent advances in psychopharmacology, the treatment approach still has important limits and shows poor efficacy on global outcomes. A potential pathway for improving clinical outcomes is that of the personalised treatment for autism, by using therapeutic drug monitoring (TDM) - a valuable tool for drugs with narrow therapeutic index - as well as systematic genetic background assessment, foreseen in future applications. However, it is already possible to implement an active surveillance programme to address safety concerns and to optimise therapeutic drug interventions in ASD.