Schizophrenia in the light of precision medicine: a time for reconsideration

Sri Lanka Journal of Psychiatry Vol 10(1) June 2019 1 Schizophrenia is a severe neurodevelopmental disorder affecting 0.7% of the global population regardless of nationality, social class, sex or ethnicity (1). It manifests between the ages of 15-25 years, is lifelong, persistent and crippling for most. There are three major symptom domains: positive, negative and cognitive symptoms (2). Psychotic symptoms such as delusions and hallucinations are terrifying and attract medical attention, but at least in part are responsive to treatment with antipsychotic medications. Conversely, negative symptoms such as social withdrawal and poverty of thought and cognitive symptoms such as impaired attention and executive dysfunction are functionally more impairing but have no effective treatments (3, 4). Many people with schizophrenia experience a gradual decline of 10 IQ points, impaired attention, memory deterioration and a decreased ability to think flexibly or creatively (executive dysfunction) (5). Negative symptoms such as social withdrawal, amotivation and anhedonia leave sufferers lonely, unable to work and often depressed (6). This symptom burden has marked psychosocial impacts, with loss of educational and vocational opportunities and ability, social isolation, reduced fertility and high rates of suicidality, up to 12 times that of the general population (3, 7). Additionally, mortality is increased and life expectancy is reduced by approximately 12 years (1). Economic costs include direct medical costs and indirect costs associated with lost productivity; this varies widely globally – from annual societal costs per patient of US dollars 5,818 in Thailand to US dollars 94,587 in Norway (8). The reason for these grim outcomes is because the illness starts in young people, and treatments are only symptomatic and partially effective. What is lacking is a precision medicine approach to schizophrenia, as has occurred in oncology, haematology and other areas of medicine (9). Ultimately, this gap is due to the failure to understand the pathology of schizophrenia, which has prevented the development of diagnostics, and disease modifying, breakthrough treatments, as well as truly preventative measures.