Are We One Step Closer to Conquering Schizophrenia?

Hallucinations. Delusions. False beliefs. All of these are characteristic symptoms of the harrowing mental disorder, schizophrenia. Not to be confused with “multiple personality disorder” (as it so often is), schizophrenia is a terribly traumatising condition in which sufferers find it incredibly difficult to think as a healthy person would, and often display impairments in memory, attention, and other cognitive abilities.

Despite being such a prevalent disease in modern day society (in 2011, there were 24 million sufferers worldwide), the underlying biology and causation of the disease has long been unclear – until now. A new study in the field has shed light on the “black box” that was the origin of schizophrenia (as described by lead researcher, Dr Steven McCarroll). Although other factors had been considered in the quest to find the cause of schizophrenia (for example, in utero conditions), it had long been established that the role of one’s DNA must be highly significant, yet only in this new research has a specific gene been identified.

Analysis of 100,000 samples of human DNA from 30 different countries revealed that a key gene related to schizophrenia is the complement component 4 (C4) gene, already known to play a role in the immune system. Highly variable in structure, the C4 gene was found to have specific alleles that when present in a person, would cause higher expression of the gene, and make them more likely to develop schizophrenia.

The reasoning behind this is thought to be the role that C4 plays in synaptic “pruning” – a process by which excess neurons are physiologically destroyed in the nervous system, to allow more efficient communication between neurons. This function of the gene was demonstrated in this study by experiments on mice, in which C4 was found to mediate the elimination of synapses. This role for C4 would provide an explanation for both the fact that schizophrenia usually strikes during late adolescence (a period of time in which synaptic pruning is especially important for development) and that sufferers of schizophrenia often have a thinner cerebral cortex, with fewer synapses than a healthy person would have.

So what are the implications for this research? It is, of course, still early days in terms of the effect this new information will have on treatment of schizophrenia. Having targeted a specific gene, however, is a huge leap forward in this field, in that now experiments can be undertaken to manipulate the gene, and try to establish its mechanism of function, so that methods to reduce the symptoms of schizophrenia can be developed (for example, repressing the gene to reduce the excessive synaptic pruning in sufferers of the disease). This study certainly holds promise for this field, and a new treatment for schizophrenia may be on the horizon much sooner than anyone could have anticipated.

Photo: Craig Finn (schizophrenia patient)