Schizophrenia is a very common disease that affects about 1% of the population. This means that in Spain there are around 500,000 sufferers. It is a very complex disorder that usually appears in adolescence. It varies greatly in both its causes and clinical presentation. It typically begins with an episode of psychosis involving distortion of reality, in the form of delusions and hallucinations.
As there is no specific test to prove that a patient has schizophrenia, the diagnosis is made exclusively on the basis of the symptoms presented by that person. When a person is diagnosed for the first time, they must be medically monitored for the first few months, even years, because the symptoms can be confused with other mental disorders.
Currently, no biomarkers are available that would allow a clear diagnosis of schizophrenia. In other words, it still cannot be detected in blood or imaging tests, molecules or signals, which could be used to confirm schizophrenia.
Studies in this field have proposed various markers, including metabolic syndrome, which involves a series of characteristics associated with cardiovascular health. For example, high cholesterol, fat accumulation around the waist, and high blood pressure.
Another proposed marker is shortening of the telomere, part of the DNA found at the end of the chromosomes. Telomeres shorten each time the cell replicates and, when they reach a certain degree of shortening, this triggers cell death.
Some studies also propose increased pulse pressure (PP) as a schizophrenia biomarker. PP is a measurement that reflects arterial elasticity. For this reason, a high pulse pressure (above 50 mmHg) indicates that the walls of the large arteries are stiff.
In addition to breakthroughs in the study of biomarkers, there have also been significant improvements in neuroimaging techniques, recovery predictors have been established in long-term follow ups (more than ten years), and there is better early antipsychotic treatment.
These studies are important milestones down a path that will significantly assist future clinical decision making, and improve the situation for people with this disorder.
To reach this goal, many more longitudinal studies must be undertaken; in other words, individuals must be observed for long periods of time. In addition, these studies must be evaluated in a standardised manner, using the same questions, in order to enable comparisons between them. In this way, we generate the most scientific evidence possible to tackle the heterogeneity and complexity of illnesses like schizophrenia.