Psychologists have made important discoveries into attention problems in schizophrenic individuals. Tobias Bast, Ph.D., and colleagues at Nottingham University in the U.K. explain that inhibitory signals between brain neurons are crucial for healthy brain activity.
But disruptions to this inhibition can cause attention problems. Hence increased brain activity is not always beneficial.
In tests on rats, the team either inhibited or disinhibited the prefrontal cortex, a brain region linked to planning, decision-making, and social behavior. This showed that both inhibiting and disinhibiting the prefrontal cortex led to attention deficits. In order to pay attention, neuron firing needed to be within a certain range.
Bast believes this is relevant for people with schizophrenia, as studies have indicated unusual neuron firing in their prefrontal cortex. Problems sustaining attention can have a significant impact on many aspects of patients’ lives, such as following conversations, driving, and keeping a job.
Full details are published in The Journal of Neuroscience.
Said Bast, “The implication of our findings is that the abnormalities we see in the prefrontal cortex of schizophrenia patients, for example, are indeed a plausible cause of the attention deficit these patients have.
“It also means that if we want to treat this pharmacologically, we can’t just boost activity of the prefrontal cortex or inactivate it, because that would actually result in impairment. What we need to do is look at restoring balance of activity through drugs which keep the activity within a certain range.”
The issue of attention problems in schizophrenia is less well-known than other more striking issues, but Bast said it is nevertheless a major problem.
“Initially people focused on the so-called ‘psychotic symptoms’, including hallucinations and delusions, so that’s what probably comes to mind when you think of schizophrenia,” he said.
“They have been in the fore because they have been so striking and that’s why referrals are made. But these can be treated, at least in a large proportion of patients, by using anti-psychotic medication, which we have had since the late 1950s.
“The problem is that unfortunately anti-psychotic drugs don’t improve cognitive deficits which are very debilitating, affecting many aspects of the patients’ lives. Cognitive deficits are a big problem and something that is currently not treated so finding something that helps this is really important.”
The team now hopes to investigate possible treatments for attention issues caused by imbalanced brain activity. Such treatments may also be beneficial for patients with early-stage Alzheimer’s disease, they said.
In the future, novel drugs that can restore balanced prefrontal activity may help overcome deficits in prefrontal-dependent attention, the researchers said.
But drugs that simply boost prefrontal activation (and cause too much activation) or reduce prefrontal activity (causing too much inhibition) would be less useful, because the treatment effect may “overshoot” either way, they warn.
“Attention’s high susceptibility to disruption by aberrant prefrontal activity implies that dysfunction in areas with strong prefrontal connectivity, such as the hippocampus, may induce attentional deficits,” they write.
Their studies “support a key role of prefrontal disinhibition in causing schizophrenia-related neurobehavioral abnormalities.”
Despite the attentional impairments in schizophrenia being well-documented, currently available drugs and psychosocial interventions have not been particularly effective. But one form of psychosocial treatment, attention-shaping, may show promise.
Attention shaping (AS) is a behavioral intervention for improving attentiveness and learning of social skills among highly distractible schizophrenia patients. It is a reward-based learning procedure, used to facilitate patients’ meeting clearly defined and individualized attentiveness and participation goals during social skills training groups.
The procedure was investigated by a team led by Dr. Steven M. Silverstein of Rutgers University, New Jersey. They say that AS “has been repeatedly demonstrated to produce significant and meaningful change in various aspects of participant attentiveness behaviors.”
So the team carried out the first randomized clinical trial of AS involving people with schizophrenia who are being treated in a partial hospital program, in which they live at home but have hospital appointments frequently throughout the week.
This showed that AS “is effective in improving attention in people with schizophrenia in these types of programs,” the team reports. They believe that the effects of AS “generalize outside of the immediate treatment context to both other treatment groups and real-world functioning.”
They conclude, “This project provides further evidence for the benefits of use of AS in the recovery-oriented treatment of people diagnosed with schizophrenia who have significant attentional impairments.”
Pezze, M. et al. Too little or too much: hypoactivation and disinhibition of medial prefrontal cortex cause attentional deficits. The Journal of Neuroscience, 4 June 2014, doi:10.1523/JNEUROSCI.3450-13.2014
Silverstein, S. M. et al. Enhancing and Promoting Recovery In Attentionally Impaired People Diagnosed With Schizophrenia: Results From A Randomized Controlled Trial Of Attention Shaping In A Partial Hospital Program. The American Journal of Psychiatric Rehabilitation. Volume 17, Issue 3, July 2014, pp. 272-305.