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Hypertension Drug Appears to Relieve Psychosis
Sodium nitroprusside is used to treat severe hypertension. But there is also evidence that it also regulates the activity of N-methyl-D-aspartate (NMDA) glutamate receptors, said the researchers.
Since blocking those receptors in animals leads to psychosis-like behavior, the researchers wondered if the drug could benefit humans with schizophrenia.
In a small randomized trial, many patients experienced a diminishing of their symptoms within four hours, while those who got a matching placebo did not, according to Serdar Dursun, M.D., Ph.D., of the University of Alberta in Edmonton, and colleagues.
The improvements lasted up to four weeks without any noticeable adverse effects.
Although the results should be considered preliminary because of the size of the study — only 20 patients — the authors said that the findings “are exciting in terms of effectiveness of the drug.”
The study involved 20 patients, in an acute phase of schizophrenia, all of whom required inpatient care. The participants were between the ages of 19 and 40 and were in the first five years since diagnosis. All were on stable antipsychotics at the time of the infusion.
Ten patients received sodium nitroprusside at 0.5 micrograms per kilogram of body weight per minute for four hours – the lowest recommended dose for humans. The remaining 10 patients got 5 percent glucose, also infused for four hours.
During the infusions and for four weeks afterward, psychiatrists monitored schizophrenia symptoms using the 18-item Brief Psychiatric Rating Scale and the negative subscale of the Positive and Negative Syndrome Scale. They also measured safety and tolerability of the drug, both physiologically and psychologically.
During the infusion, they found a positive effect on the brief rating scale that was apparent by the second hour. The effect was seen in all patients getting the drug, but not in any placebo patient.
A similar rapid effect was observed on the positive-negative symptom scale. On both scales, the improvement continued for at least four weeks, the researchers reported.
The findings offer further support that NMDA receptors are underperforming in schizophrenia, commented Joseph Coyle, M.D., of Harvard Medical School.
Coyle noted that the results are consistent with other studies that involve those receptors. But, he said, the current study remains too small to justify changes in clinical practice.
“Caution must be exercised until sufficiently powered clinical trials of nitroprusside are performed in patients with schizophrenia,” said Coyle.
The researchers note that participants were fairly early in their disease course. Future research, they said, should test the drug in patients with long-term illness.
They also noted that the study allowed for changes to supplemental medications (such as benzodiazepines and analgesics) 48 hours after the infusion and to antipsychotics after seven days. Because of this, there is “uncertainty to the antipsychotic effects of sodium nitroprusside alone at later time points.”
Source: JAMA Psychiatry
schizophrenia word collage photo by shutterstock.
Memory Problems in Seniors Tied to Changing Way Events are Perceived
The study, conducted at Washington University in St. Louis, found that perception is influenced by a part of the brain called the medial temporal lobe (MTL), which declines in functioning in old age.
“When you think back on what you did yesterday, you don’t just press ‘play’ and watch a continuous stream of 24 hours,” said psychological scientist Heather Bailey, Ph.D., of Washington University in St. Louis, who led the study. “Your brain naturally chunks the events in your day into discrete parts.”
Bailey and her colleagues hypothesized that older adults may have difficulty with memory for everyday events because they don’t segment them in the same way as they’re happening.
In the study, older adults, including some who had Alzheimer’s type dementia, watched short movies of people doing everyday tasks, such as a woman making breakfast or a man building a Lego ship. They were asked to separate the movie into chunks by pressing a button whenever they thought one part of the activity was ending and a new part beginning.
Afterward, the researchers asked the participants to recall what happened in the movie. They also measured the size of the older adults’ MTL using structural magnetic resonance imaging (MRI).
“The older adults who showed atrophy in the MTL weren’t as good at remembering the everyday activities, and they weren’t as good at segmenting and chunking the events as they were happening,” said Bailey.
“MTL size accounted for a huge portion of the relationship that we saw between participants’ ability to segment and their memory for the events.”
According to the researchers, this means that what people are doing while they are going through their daily lives — how well they’re segmenting their experiences into separate memories — has an influence on how well they will remember those experiences in the future. And how well they are able to segment and remember is partly due to how well their MTL is functioning, she adds.
Focusing on how to better form new memories may be one way to improve older adults’ memory for everyday events, even for those adults who have clinical diagnoses like Alzheimer’s, she noted.
“Alzheimer’s disease attacks the MTL in the early stages of the disease,” she said. “But even with MTL atrophy you may be able to train people to chunk better, which might help them to remember their everyday activities better, too.”
Bailey and colleagues hope to further investigate the link between event perception and memory to see if they can combat memory impairment in older adults.
“We want to see if we can intervene at an early point in perception, if it will affect memory,” she said.
The study was published in Psychological Science.
Source: Washington University in St. Louis
Brain abstract photo by shutterstock.
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