Depressed adolescents' brains shown to mute distressing information
Scientists have measured brain activity in young people with and without depression, and found that the brains of depressed adolescents give a muted reaction to distressing images. Previous research with depressed adults does not show this effect, implying that brain development in adolescence may have specific vulnerabilities to unsettling information, and that perhaps the depressed adolescent brain avoids information which in the end could aggravate the depression. Antidepressant treatment was shown to restore this depressed brain activity to ‘healthy’ levels. This work was presented at the ECNP conference.
The researchers, from the University of Oxford, compared brain activity of 29 depressed adolescents with that of 16 healthy adolescents, aged 13 to 18. They found that when depressed adolescents were shown a series of photos of distressing images, there was reduced activity, as shown on an fMRI brain scan, (compared to non-depressed adolescents) in brain areas related to visual processing; the occipital pole (which processes visual information, found at the rear of the brain) and the fusiform gyrus (which is involved in the processing of faces, body and colours, found near the brain stem). The images depicted scenarios such as someone crying, someone visibly hurt, someone being attacked.
Lead researcher, Dr Liliana Capitão, University of Oxford, said:
'The ability to regulate emotions is key to social and emotional development in adolescents. What we have seen in this study makes us believe that depressed adolescents may avoid distressing information, which could potentially intensify their experience of depression. There are also other possible interpretations for this intriguing pattern, so further research is needed to confirm our ideas. For instance, this could also reflect a form of “emotional numbness”, where depressed adolescents shut down their emotions and do not feel “involved” in what’s happening around them, or even reflect difficulties with taking another person’s perspective, as the images showed distressing situations that were happening to others. This effect has not been found in previous work using the same distressing images in adults with depression, which could imply that there are potential vulnerabilities in the brains of depressed adolescents which are not found in the brains of depressed adults.'
Read more about this research, which is currently under review in Psychological Medicine.
Intestinal drug shown to boost memory and cognition
The development of drugs to treat cognitive problems in patients with mental illness may be a step closer after a team of researchers discovered that an existing drug – used to treat constipation – may be able to boost our ability to think more clearly.
Severe psychiatric disorders can have a devastating impact on a patient’s life. Cognitive impairments - ranging from decreased attention and working memory to disrupted social cognition and language - are widespread in psychiatric disorders such as major depression, schizophrenia, and bipolar disorder. These common problems are poorly treated with current medications and often have a large impact on people’s lives, and so scientists are searching for ways of improving or restoring these functions.
Previous animal studies have shown that the drugs which target one of the serotonin receptors (the 5-HT4 receptor) have shown promise in improving cognitive function (serotonin is the neurotransmitter which is targeted by SSRI antidepressants). However, it has been difficult to translate these animal findings into humans because of worries about side effects. Now a group of UK researchers have tested an existing approved drug, prucalopride, which targets the 5-HT4 receptor, and found that it may improve cognition. Prucalopride is primarily prescribed for constipation, and has an acceptable level of side effects if taken under medical supervision.
Presenting the work at the ECNP conference (with simultaneous publication), lead researcher, Dr Angharad de Cates of the University of Oxford said:
'Participants who had taken prucalopride for 6 days performed much better than those receiving placebo on the memory test; the prucalopride group identified 81% of previously viewed images versus 76% in the placebo group. Statistical tests indicate that this was a fairly large effect – such an obvious cognitive improvement with the drug was a surprise to us.'
Read more about this research, Déjà-vu? Neural and behavioural effects of the 5-HT4 receptor agonist, prucalopride, in a hippocampal-dependent memory task, published in Translational Psychiatry.
For more information about the ECNP Conference 2021.