British scientists believe they have found specific patterns of brain activity in children and young people which could be signs or "markers" of those who will later go on to develop mental illnesses such as schizophrenia.
Researchers from Nottingham University, who presented their study at the Forum for European Neuroscience in Amsterdam, said the patterns suggest it may be possible in future to identify those at risk of becoming ill before they develop symptoms.
"If we can identify people who are at particularly high risk of developing schizophrenia, perhaps using neurocognitive brain markers, then we might be able to reduce that risk and also help them to function better," said Dr Maddie Groom, who worked on the study and gave a briefing to reporters in London.
"If we give them a better start, they may encounter the illness in a more positive way and not get quite so ill."
Hundreds of millions of people worldwide are affected by mental, behavioural and neurological illnesses such as schizophrenia, attention deficit hyperactivity disorder (ADHD), depression, epilepsy and dementia.
Many people who go on to develop diverse mental health problems will have a history of behavioural problems going back to childhood, but experts say the problem with finding them at that stage is that differences then are often extremely subtle.
In one study, Groom and her colleagues investigated looked at the healthy siblings of people with schizophrenia, who also have a very slightly increased risk of developing schizophrenia compared with the general population.
Using brain imaging to read activity levels, the scientists asked the siblings to perform task which involved playing an alien-zapping computer game in which they needed to respond quickly, and crucially, halt the urge to respond if the wrong kind of alien popped up. The task was called a "go, no-go" task.
"When we measured the brain activity of the siblings of people with schizophrenia, their brain activity was reduced at the time when they needed to pay attention to the stimulus, and when they needed to inhibit their response," Groom explained.
She said this suggested the subtle differences in brain activity may act as a risk marker for the disorder.
In a second study, scientists compared brain activity of children with ADHD -- a mental disorder that affects between 8 and 12 percent of children, and 4 percent of adults worldwide.
The researchers used the same "go, no-go" task in various scenarios, including when the children were taking their medication, Ritalin, and when they were not, and then using an additional system of rewards and penalties.
Millions of people take ADHD drugs including Novartis Ritalin, which is known generically as methylphenidate, and Shire Plc's Adderall and Vyvanse. In the United States alone, 2008 sales for these drugs was about $4.8 billion, according to data from IMS Health.
Groom's results showed that children who were taking medication, and children given an incentive, performed better than those who had neither medicines nor incentives.
This suggests, Groom said, that doctors may be able to find new ways to treat children with ADHD using a combination of behavioural strategies and drugs. (Editing by Jon Boyle)