A University of Geneva study carried out in hospitals in the Swiss city suggests why schizophrenia and apathy go hand in hand.
The study, published in the journal Brain, suggests several potential treatments, including brain stimulation and targeted psychotherapy.
Schizophrenia, a neuropsychiatric disorder characterized by multiple symptoms, affects up to 1% of the population.
One of the most common symptoms, and one for which there is no treatment, is apathy and lack of motivation, according to the study.
It compared neural activation during a reward-based game, in a study carried out by a team from the University of Geneva and the University Hospitals of Geneva.
They collaborated with researchers from the non-governmental group Charite Berlin, deciphering the neural bases of this schizophrenia.
The brains of people who have schizophrenia are unable to discriminate between different levels of reward in a sufficiently subtle way, hampering their motivation to undertake everyday tasks, it said.
The scientists enrolled 152 volunteers – 86 people who have schizophrenia and 66 controls of similar age and gender – to play a reward game in an MRI scanner to observe the activation of their brain regions.
- Lack of motivation
"Lack of motivation is at the root of the difficulties encountered by people suffering from schizophrenia in pursuing their studies, holding down a job, or engaging in social contacts," said Geneva Hospitals and University psychiatry professor Stefan Kaiser.
When discussing schizophrenia, people first think of hallucinatory or delusional symptoms, such as ideas of persecution.
However, the study found that apathy and lack of motivation are less visible and are just as burdensome in everyday life.
"Furthermore, the antipsychotics prescribed for hallucinatory phenomena and delusions have no effect on motivation, for which there is currently no effective treatment," said Kaiser.
The experiment took place in three stages: an assessment of motivation in different contexts, an initial game session, and, three months later, a second session identical to the first to measure the stability of the cerebral response over time.
By deciphering the neural response to a possible reward in people who have schizophrenia, the team suggested an origin to the lack of motivation, one of the symptoms of the illness.
According to the researchers, the results open several therapeutic avenues that precisely target the neuronal activation defect.
"For example, psychotherapy targeting the perception of reward and pleasure to reinforce motivation to engage in social behavior, or the use of non-invasive brain stimulation, a technique already used to treat depression" could be used, explained researcher Mariia Kaliuzhna.
"However, these techniques are complex and must be validated in clinical trials before any clinical implementation,” she added.
