According to a recent small study published in BMC Psychiatry, deficits in motivation may not be accounted for entirely by institutionalization or long-term treatment in patients with schizophrenia and other forms of psychosis. According to Graham Murray, M.D., Ph.D., these deficits are present at the first episode of psychosis. Dr. Murray’s team measured “reinforcement-related speeding,” response time in relationship to the chance for reward, in patients with a first episode of psychosis; only four out of eighteen of these patients improved their response time to increase their chances for reward. Conversely, 17 out of 19 from a control group improved their response time to gain reward. The researchers believe that abnormalities in the brain’s reward center account for motivation deficits in psychosis. According to Dr. Murray, “Patients with psychosis already have motivational deficits the first time they present to health services… understanding the brain basis of these problems will ultimately help in developing new treatments.” The following is an excerpt of an article from Medpage Today that reviews the study:
It has been proposed that there are abnormalities in the brain’s reward system and in the processing of incentive motivation in psychosis, and that dopamine dysfunction may be responsible, but this has not been well evaluated clinically, the researchers said.
So the investigators recruited 18 patients (mean age 23, nine males) who had symptoms of psychosis for the first time and 19 healthy controls (mean age 25, nine males) to complete the Cued Reinforcement Reaction Time Task, which measures motivationally driven behavior.
Eleven of the 18 psychosis patients were taking atypical antipsychotics, including olanzapine (Zyprexa) (three), risperidone (Risperdal) (two), quetiapine (Seroquel) (two), clozapine (Clozaril) (one), aripiprazole (Abilify) (two), and amisulpride (one).
A year after the evaluation, nine patients were diagnosed by a psychiatrist with schizophrenia, two with schizoaffective disorder, five with bipolar disorder, one with delusional disorder, and one with a psychosis not otherwise specified.
On the task, all participants were asked to choose which of a simple set of three shapes did not belong in 96 trials, with varying likelihood of reward indicated by three different colors as the test progressed. Previous studies in healthy participants have shown increased reaction times associated with a higher likelihood of reward, the researchers said.