Mania is a possible but rare side effect of treatment with antidepressant medication in adults, but there is little known about its occurrence in children and adolescents. A newly published paper in JAMA Psychiatry investigated this, finding no evidence of mania/hypomania induced by antidepressants by 12 weeks after treatment initiation. However, caution is necessary in treatment for children with more severe depression or where a parent has bipolar disorder.
“In children and adolescents with unipolar depression, we did not find evidence of antidepressant-induced mania/hypomania by 12 weeks after treatment initiation”, says first author Suvi Virtanen, postdoctoral researcher at Karolinska Insitutet. “This corresponds to the timeframe for antidepressants to exert their psychotropic effect and when treatment-induced mania is expected to emerge. Hospitalisations, parental bipolar disorder, and the use of antipsychotics and antiepileptics were the most important predictors of mania/hypomania.”
Antidepressants are increasingly prescribed to paediatric patients with unipolar depression (as opposed to bipolar depression which is seldom diagnosed in childhood), but little is known about the risk of treatment-emergent mania (ie, the transition from depression into mania shortly after the initiation of antidepressant treatment). Previous research suggests paediatric patients may be particularly vulnerable to this adverse outcome. The results provide complementary information to randomised clinical trials (RCTs) from a large cohort of patients treated in a real-world setting.
The researchers conducted a register-based study on children and adolescents, aged 4–17, diagnosed with unipolar depression between 2006 and 2019. They applied the emulation of target trial framework to guide the study design and analysis, reducing the bias of observational studies and mimicking a RCT.
Antidepressant treatment was unrelated to the risk of mania/hypomania, suggesting other characteristics are more relevant when evaluating which patients may have an increased risk of switching from unipolar depression into mania. “Our model using administrative information from several national registers had a moderate predictive ability, suggesting it is possible to identify patients at high risk for mania/hypomania with a prognostic clinical prediction model. The model has potential to be improved in later work”, says senior author Zheng Chang, Principal Researcher at the Department of Medical Epidemiology and Biostatistics.
Researchers in Japan have shown that the commonly prescribed antipsychotic drug aripiprazole helps reduce sleep disruptions in patients with certain psychiatric disorders by improving their natural entrainment to light and dark cycles. Their findings are published in Frontiers in Neuroscience.
Many patients with psychiatric conditions, such as bipolar disorder and major depressive disorder, frequently experience disruptions in their sleep–wake cycles. Research has shown that the administration of aripiprazole, a commonly prescribed antipsychotic drug, alleviates the symptoms of circadian sleep disorders in these patients. This improvement may be attributed to the effects of aripiprazole on the circadian central clock, specifically the hypothalamic suprachiasmatic nucleus (SCN), which regulates various circadian physiological rhythms, including the sleep–wake cycle, in mammals. However, the precise mechanism through which aripiprazole addresses these sleep disorder symptoms remains elusive.
Researchers from the University of Tsukuba have discovered that aripiprazole can directly affect the mammalian central circadian clock; specifically, it can modulate the photic entrainment in mice. Located in the hypothalamic suprachiasmatic nucleus (SCN), the central circadian clock comprises clock neurons that synchronize with each other, maintaining a roughly 24-hour rhythm. Simultaneously, SCN is receptive to external inputs like light, aligning itself with the environmental light-dark cycle. The researchers have found that aripiprazole disrupts the synchronization among the clock neurons in the SCN, heightening the responsiveness of these neurons to light stimuli in mice. Additionally, aripiprazole influences intracellular signalling within the SCN by targeting the serotonin 1A receptor, a prominent receptor in the SCN.
These findings suggest that the efficacy of aripiprazole in alleviating circadian rhythm sleep disorder symptoms in psychiatric patients might be attributed to the modulation of the circadian clock by the drug. This study expands the potential clinical usage of aripiprazole as a treatment for circadian rhythm sleep disorders.
A new study suggests that depression after traumatic brain injury (TBI) could be a clinically distinct disorder rather than traditional major depressive disorder. The findings, which are published in Science Translational Medicine, hold important implications for patient treatment.
“Our findings help explain how the physical trauma to specific brain circuits can lead to development of depression. If we’re right, it means that we should be treating depression after TBI like a distinct disease,” said corresponding author Shan Siddiqi, MD, from Brigham and Women’s Hospital,. “Many clinicians have suspected that this is a clinically distinct disorder with a unique pattern of symptoms and unique treatment response, including poor response to conventional antidepressants – but until now, we didn’t have clear physiological evidence to prove this.”
Siddiqi, who led the study, was motivated by a patient he shared with David Brody, MD, PhD, a co-author on the study and a neurologist at Uniformed Services University. The two started a small clinical trial that used personalised brain mapping to target brain stimulation as a treatment for TBI patients with depression. In the process, they noticed a specific pattern of abnormalities in these patients’ brain maps.
The current study included 273 adults with TBI, usually from sports injuries, military injuries, or car accidents. People in this group were compared to other groups who did not have a TBI or depression, people with depression without TBI, and people with posttraumatic stress disorder. Study participants went through a resting-state functional connectivity MRI, a brain scan that looks at how oxygen is moving in the brain. These scans gave information about oxygenation in up to 200 000 points in the brain at about 1000 different points in time, leading to about 200 million data points in each person. Based on this information, a machine learning algorithm was used to generate an individualised map of each person’s brain.
The location of the brain circuit involved in depression was the same among people with TBI as people without TBI, but the nature of the abnormalities was different. Connectivity in this circuit was decreased in depression without TBI and was increased in TBI-associated depression. This implies that TBI-associated depression may be a different disease process, leading the study authors to propose a new name: “TBI affective syndrome.”
“I’ve always suspected it isn’t the same as regular major depressive disorder or other mental health conditions that are not related to traumatic brain injury,” said Brody. “There’s still a lot we don’t understand, but we’re starting to make progress.”
With so much data, the researchers were not able to do detailed assessments of each patient beyond brain mapping. To overcome this limitation, investigators would like to assess participants’ behaviour in a more sophisticated way and potentially define different kinds of TBI-associated neuropsychiatric syndromes.
Siddiqi and Brody are also using this approach to develop personalized treatments. Originally, they set out to design a new treatment in which they used this brain mapping technology to target a specific brain region for people with TBI and depression, using transcranial magnetic stimulation (TMS). They enrolled 15 people in the pilot and saw success with the treatment. Since then, they have received funding to replicate the study in a multicentre military trial.
“We hope our discovery guides a precision medicine approach to managing depression and mild TBI, and perhaps even intervene in neuro-vulnerable trauma survivors before the onset of chronic symptoms,” said Rajendra Morey, MD, a professor of psychiatry at Duke University School of Medicine, and co-author on the study.
Depression and anxiety are thought to increase a person’s risk of developing cancer, but research results have been inconclusive. In an analysis of multiple studies from the Netherlands, the UK, Norway, and Canada, investigators found that depression and anxiety are not linked to higher risks for most types of cancer among this population. The analysis is published in the journal CANCER.
Experts have suspected that depression and anxiety may increase cancer risk by affecting a person’s health-related behaviours or by having biological effects on the body that support cancer development. Some research has supported an association between depression, anxiety, and cancer incidence, while other investigations have found no or negligible associations.
To provide additional insights, Lonneke A. van Tuijl, PhD, of the University Medical Center Groningen, and her colleagues examined data from the international Psychosocial Factors and Cancer Incidence consortium, which includes information from 18 prospective study groups with more than 300 000 adults from the Netherlands, the United Kingdom, Norway, and Canada.
The team found no associations between depression or anxiety and overall, breast, prostate, colorectal, and alcohol-related cancers during a follow-up of up to 26 years. The presence of depression or anxiety was linked with a 6% higher risk of developing lung cancer and smoking-related cancers, but this risk was substantially reduced after adjusting for other cancer-related risk factors including smoking, alcohol use, and body mass index. Therefore, this analysis supports the importance of addressing tobacco smoking and other unhealthy behaviours including those that may develop as a result of anxiety or depression.
“Our results may come as a relief to many patients with cancer who believe their diagnosis is attributed to previous anxiety or depression,” said Dr van Tuijl. “However, further research is needed to understand exactly how depression, anxiety, health behaviours, and lung cancer are related.”
A low-cost version of ketamine to treat severe depression has performed strongly in a placebo-controlled double-blind trial. Results published in the British Journal of Psychiatry showed that more than one in five participants achieved total remission from their symptoms after a month of bi-weekly injections, while a third had their symptoms improve by at least 50%.
“For people with treatment-resistant depression – so those who have not benefitted from different modes of talk-therapy, commonly prescribed antidepressants, or electroconvulsive therapy – 20 per cent remission is actually quite good,” lead researcher Professor Colleen Loo says.
“We found that in this trial, ketamine was clearly better than the placebo – with 20 per cent reporting they no longer had clinical depression compared with only 2 per cent in the placebo group. This is a huge and very obvious difference and brings definitive evidence to the field which only had past smaller trials that compared ketamine with placebo.”
How the trial worked
The researchers, led by UNSW Sydney and the affiliated Black Dog Institute, recruited 179 people with treatment-resistant depression. All were given an injection of either a generic form of ketamine that is already widely available in Australia as a drug for anaesthesia and sedation – or placebo. Participants received two injections a week in a clinic where they were monitored for around two hours while acute dissociative and sedative effects wore off, usually within the first hour. The treatment ran for a month and participants were asked to assess their mood at the end of the trial and one month later.
In this double-blind trial, a placebo was chosen that also causes sedation, to improve treatment masking. Midazolam is a sedative normally administered before a general anaesthetic, while in many previous studies the placebo was saline.
“Because there are no subjective effects from the saline, in previous studies it became obvious which people were receiving the ketamine and which people received placebo,” Prof Loo says.
“In using midazolam – which is not a treatment for depression, but does make you feel a bit woozy and out of it – you have much less chance of knowing whether you have received ketamine, which has similar acute effects.”
Other features of the recent trial that set it apart from past studies included accepting people into the trial who had previously received electroconvulsive therapy (ECT).
“People are recommended ECT treatment for their depression when all other treatments have been ineffective,” Prof. Loo says.
“Most studies exclude people who have had ECT because it is very hard for a new treatment to work where ECT has not.”
Another difference about this trial was that the drug was delivered subcutaneously (injected into the skin) rather than by drip, thus greatly reducing time and medical complexity. The study is also the largest in the world to date that compares generic ketamine with placebo in treating severe depression.
Much more affordable
Apart from the positive results, one of the standout benefits of using generic ketamine for treatment-resistant depression is that it is much cheaper than the patented S-ketamine nasal spray currently in use in Australia. Where S-ketamine costs about AUS$800 (R9 600) per dose, the generic ketamine is a mere fraction of that, costing as little as AUS$5 (R60), depending on the supplier and whether the hospital buys it wholesale. On top of the cost for the drug, patients need to pay for the medical care they receive to ensure their experience is safe – which at Black Dog Institute clinics, comes to AUS$350 (R4200) per session.
“With the S-ketamine nasal spray, you are out of pocket by about AUS$1200 for every treatment by the time you pay for the drug and the procedure, whereas for generic ketamine, you’re paying around AUS$300-350 for the treatment including the drug cost,” Prof Loo says.
She adds that for both S-ketamine and generic ketamine treatments, the positive effects often wear off after a few days to weeks, so ongoing treatment may be required, depending on someone’s clinical situation. But the prohibitive costs of the drug and procedure make this an unsustainable proposition for most.
The researchers will next be looking at larger trials of generic ketamine over longer periods, and refining the safety monitoring of treatment.
A small South African study published in the open-access journal PLOS ONE suggests that programmes promoting interaction between retirement home residents and children may provide quality of life improvements and could help manage residents’ anxiety and depression.
Among retirement home residents, previous research has shown that common mental health conditions often go undetected and untreated. These conditions, which include anxiety and depression, are typically treated with a combination of drugs and non-pharmacological interventions.
One intervention is the Eden Alternative, which identifies loneliness, helplessness and boredom as key challenges to overcome provide a higher quality of life. Evidence suggests that programmes that enable older adults to regularly interact with children may improve mental health, but these have mostly been done outside of retirement homes and few have looked at such programmes in South Africa.
To deepen the understanding of potential benefits of intergenerational interactions, Elizabeth Jane Earl and Debbie Marais of Stellenbosch University, South Africa, conducted a study at a retirement home in South Africa. Residents were able to regularly interact with children who attend an onsite preschool. Activities include playing games, doing puzzles, reading, or singing with the children.
Ten female residents were recruited and invited to complete a questionnaire evaluating their anxiety and depression levels, as well as asking them to describe their experiences with the children. Four of the participants were screened as possible having anxiety, depression, or both. The participants all took part in the same interactions, though to varying degrees of participation.
Generally, the participants reported positive experiences with the children. Analysing their responses, the researchers found that the interactions fostered a sense of purpose and belonging, fond reminiscences of their own childhood and a positive influence on mood and emotions. Recollections of childhood also sparked a sense of playfulness and positive self-evaluation. They noted that the participants differed in their preconceptions of children, which might have affected their experiences.
The authors wrote that, “Interactions with children promote a sense of belonging and purpose, evoke reminiscence, and positively influence the mental well-being of older persons.”
Based on their findings, Earl and Marais concluded that intergenerational interaction programmes may help manage the mental health conditions that are common for retirement home residents. They suggest that trained staff facilitate the interaction, preparing the children and residents, and should be voluntary, which helps preserve the residents’ agency. Running the interaction as a regular programme should help build bonds and give the residents something to look forward to. Additionally, there should be an educational aspect for the children, giving the residents a sense of purpose.
Looking to the future, they wrote that larger studies would be able to better outline the benefits of such programmes.
In a new study, scientists at Stanford Medicine have described a new category of depression, the cognitive biotype, which accounts for 27% of depressed patients and is not effectively treated by commonly prescribed antidepressants. The findings were reported in JAMA Network.
For these patients, cognitive tasks showed difficulty in planning ahead, self-control, sustaining focus despite distractions and suppressing inappropriate behaviour; imaging showed decreased activity in two brain regions responsible for those tasks.
Because depression has traditionally been defined as a mood disorder, doctors commonly prescribe selective serotonin reuptake inhibitors (SSRIs), but these are less effective for patients with cognitive dysfunction. Researchers said that targeting these cognitive dysfunctions with less commonly used antidepressants or other treatments may alleviate symptoms and help restore social and occupational abilities.
The study is part of a broader effort by neuroscientists to find treatments that target depression biotypes, according to the study’s senior author, Leanne Williams, PhD, professor of psychiatry and behavioural sciences.
“One of the big challenges is to find a new way to address what is currently a trial-and-error process so that more people can get better sooner,” Williams said. “Bringing in these objective cognitive measures like imaging will make sure we’re not using the same treatment on every patient.”
Finding the biotype
In the study, 1008 adults with previously unmedicated major depressive disorder were randomly given one of three widely prescribed typical antidepressants: escitalopram (Lexapro) or sertraline (Zoloft), which act on serotonin, or venlafaxine-XR (Effexor), which acts on both serotonin and norepinephrine. Seven hundred and twelve of the participants completed the eight-week regimen.
Before and after treatment with the antidepressants, the participants’ depressive symptoms were measured using two surveys – one, clinician-administered, and the other, a self-assessment, which included questions related to changes in sleep and eating. Measures on social and occupational functioning, as well as quality of life, were tracked as well.
The participants also completed a series of cognitive tests, before and after treatment, measuring verbal memory, working memory, decision speed and sustained attention, among other tasks.
Before treatment, scientists scanned 96 of the participants using functional magnetic resonance imaging as they engaged in a task called the “GoNoGo” that requires participants to press a button as quickly as possible when they see “Go” in green and to not press when they see “NoGo” in red. The fMRI tracked neuronal activity by measuring changes in blood oxygen levels, which showed levels of activity in different brain regions corresponding to Go or NoGo responses. Researchers then compared the participants’ images with those of individuals without depression.
The researchers found that 27% of the participants had more prominent symptoms of cognitive slowing and insomnia, impaired cognitive function on behavioural tests, as well as reduced activity in certain frontal brain regions – a profile they labelled the ‘cognitive biotype’.
“This study is crucial because psychiatrists have few measurement tools for depression to help make treatment decisions,” said Laura Hack, MD, PhD, the lead author of the study and an assistant professor of psychiatry and behavioural sciences. “It’s mostly making observations and self-report measures. Imaging while performing cognitive tasks is rather novel in depression treatment studies.”
Pre-treatment fMRI showed those with the cognitive biotype had significantly reduced activity in the dorsolateral prefrontal cortex and dorsal anterior cingulate regions during the GoNoGo task compared with the activity levels in participants who did not have the cognitive biotype. Together, the two regions form the cognitive control circuit, which is responsible for limiting unwanted or irrelevant thoughts and responses and improving goal selection, among other tasks.
After treatment, the researchers found that for the three antidepressants administered, the overall remission rates were 38.8% for participants with the newly discovered biotype and 47.7% for those without it. This difference was most prominent for sertraline, for which the remission rates were 35.9% and 50% for those with the biotype and those without, respectively.
“Depression presents in different ways in different people, but finding commonalities – like similar profiles of brain function – helps medical professionals effectively treat participants by individualising care,” Williams said.
Depression isn’t one size fits all
Williams and Hack propose that behaviour measurement and imaging could help diagnose depression biotypes and lead to better treatment. A patient could complete a survey on their own computer or in the doctor’s office, and if they are found to display a certain biotype, they might be referred to imaging for confirmation before undergoing treatment.
Researchers under Williams and Hack are studying another drug, guanfacine, that specifically targets the dorsolateral prefrontal cortex region. They believe this treatment could be more effective for patients with the cognitive subtype.
Williams and Hack hope to conduct studies with participants who have the cognitive biotype, comparing different types of medication with treatments such as transcranial magnetic stimulation (TMS) and cognitive behavioural therapy.
“I regularly witness the suffering, the loss of hope and the increase in suicidality that occurs when people are going through our trial-and-error process,” Hack said. “And it’s because we start with medications that have the same mechanism of action for everyone with depression, even though depression is quite heterogeneous. I think this study could help change that.”
It has been believed speed of information transmitted among regions of the brain stabilised during early adolescence. A study in Nature Neuroscience has instead found that transmission speeds continue to increase into early adulthood, which may explain the emergence of mental health problems over this period. In fact, transmission speeds increase until around age 40, reaching a speed twice that of a 4-year old child.
As mental health problems such as anxiety, depression and bipolar disorders can emerge in late adolescence and early adulthood, a better understanding of brain development may lead to new treatments.
“A fundamental understanding of the developmental trajectory of brain circuitry may help identify sensitive periods of development when doctors could offer therapies to their patients,” says senior author Dora Hermes, PhD, a biomedical engineer at Mayo Clinic.
Called the human connectome, the structural system of neural pathways in the brain or nervous system develops as people age. But how structural changes affect the speed of neuronal signalling has not been well described.
“Just as transit time for a truck would depend on the structure of the road, so does the transmission speed of signals among brain areas depend on the structure of neural pathways,” Dr Hermes explains. “The human connectome matures during development and aging, and can be affected by disease. All these processes may affect the speed of information flow in the brain.” In the study, Dr Hermes and colleagues stimulated pairs of electrodes with a brief electrical pulse to measure the time it took signals to travel among brain regions in 74 research participants between the ages of 4 and 51. The intracranial measurements were done in a small population of patients who had electrodes implanted for epilepsy monitoring at University Medical Center Utrecht, Netherlands.
The response delays in connected brain regions showed that transmission speeds in the human brain increase throughout childhood and even into early adulthood. They plateau around 30 to 40 years of age.
The team’s data indicate that adult transmission speeds were about two times faster compared to those typically found in children. Transmission speeds also were typically faster in 30- or 40-year-old subjects compared to teenagers.
Brain transmission speed is measured in milliseconds, a unit of time equal to one-thousandth of a second. For example, the researchers measured the neuronal speed of a 4-year-old patient at 45 milliseconds for a signal to travel from the frontal to parietal regions of the brain. In a 38-year-old patient, the same pathway was measured at 20 milliseconds. For comparison, the blink of an eye takes about 100 to 400 milliseconds.
The researchers are working to characterise electrical stimulation-driven connectivity in the human brain. One of the next steps is to better understand how transmission speeds change with neurological diseases. They are collaborating with paediatric neurosurgeons and neurologists to understand how diseases change transmission speeds compared to what would be considered within the normal range for a certain age group.
Scientists have developed two new drug candidates for potentially treating addiction and depression, modelled on the pharmacology of a traditional African psychedelic plant medicine called ibogaine. At very low doses, these new compounds were able to blunt symptoms of both conditions in mice.
The study, published in Cell, took inspiration from ibogaine’s impact on the serotonin transporter (SERT), which is also the target of selective serotonin reuptake inhibitor (SSRI) drugs, such as fluoxetine. A team of scientists from UC San Francisco and Yale and Duke universities virtually screened 200 million molecular structures to find ones that blocked SERT in the same way as ibogaine.
“Some people swear by ibogaine for treating addiction, but it isn’t a very good drug. It has bad side effects, and it’s not approved for use in the US,” said Brian Shoichet, PhD, co-senior author and professor in the UCSF School of Pharmacy. “Our compounds mimic just one of ibogaine’s many pharmacological effects, and still replicate its most desirable effects on behaviour, at least in mice.”
Dozens of scientists from the laboratories of Shoichet, Allan Basbaum, PhD, and Aashish Manglik, MD, PhD, (UCSF); Gary Rudnick, PhD, (Yale); and Bill Wetsel, PhD, (Duke) helped demonstrate the real-world promise of these novel molecules, which were initially identified using Shoichet’s computational docking methods.
Docking involves systematically testing virtual chemical structures for binding with a protein, enabling scientists to identify new drug leads without having to synthesise them in the lab. “This kind of project begins with visualizing what kinds of molecules will fit into a protein, docking the library, optimising and then relying on a team to show the molecules work,” said Isha Singh, PhD, a co-first author of the paper who did the work as a postdoc in Shoichet’s lab. “Now we know there’s a lot of untapped therapeutic potential in targeting SERT.”
Optimising a shaman’s cure
Ibogaine is found in the roots of the iboga plant, which is native to central Africa, and has been used for millennia during shamanistic rituals. In the 19th and 20th centuries, doctors in Europe and the US experimented with its use in treating a variety of ailments, but the drug never gained widespread acceptance and was ultimately made illegal in many countries.
Part of the problem, Shoichet explained, is that ibogaine interferes with many aspects of human biology.
“Ibogaine binds to hERG, which can cause heart arrhythmias, and from a scientific standpoint, it’s a ‘dirty’ drug, binding to lots of targets beyond SERT,” Shoichet said. “Before this experiment, we didn’t even know if the benefits of ibogaine came from its binding to SERT.”
Shoichet, who has used docking on brain receptors to identify drugs to treat depression and pain, became interested in SERT and ibogaine after Rudnick, an expert on SERT at Yale, spent a sabbatical in his lab. Singh picked up the project in 2018, hoping to turn the buzz around ibogaine into a better understanding of SERT.
It was the Shoichet lab’s first docking experiment on a transporter – a protein that moves molecules into and out of cells – rather than a receptor. One round of docking whittled the virtual library from 200 million to just 49 molecules, 36 of which could be synthesised. Rudnick’s lab tested them and found that 13 inhibited SERT.
The team then held virtual-reality-guided “docking parties,” to help Singh prioritise five molecules for optimization. The two most potent SERT inhibitors were shared with Basbaum and Wetsel’s teams for rigorous testing on animal models of addiction, depression and anxiety.
“All of a sudden, they popped – that’s when these drugs looked a lot more potent than even paroxetine [Paxil],” Shoichet said.
Manglik, an expert with cryo-electron microscopy (cryo-EM), confirmed that one of the two drugs, dubbed ‘8090,’ fit into SERT at the atomic level in a way that closely resembled Singh and Shoichet’s computational predictions. The drugs inhibited SERT in a similar way to ibogaine, but unlike the psychedelic, their effect was potent and selective, with no spillover impacts on a panel of hundreds of other receptors and transporters.
“With this sort of potency, we hope to have a better therapeutic window without side effects,” Basbaum said. “Dropping the dose almost 200-fold could make a big difference for patients.”
Problems with the brain’s ability to ‘prune’ itself of unnecessary connections may underlie a wide range of mental health disorders that begin during adolescence, according to research published in Nature Medicine.
The findings, from an international collaboration, led by researchers in the UK, China and Germany, may help explain why people are often affected by more than one mental health disorder, and may in future help identify those at greatest risk.
One in seven adolescents (aged 10-19 years old) worldwide experiences mental health disorders, according to the World Health Organization (WHO). Depression, anxiety and behavioural disorders, such as attention deficit hyperactivity disorder (ADHD), are among the leading causes of illness and disability among young people, and adolescents will commonly have more than one mental health disorder.
Many mental health problems emerge during adolescence, such as depression and anxiety, which manifest as ‘internalising’ symptoms, including low mood and worrying. Other conditions such as attention deficit hyperactivity disorder (ADHD) manifest as ‘externalising’ symptoms, such as impulsive behaviour.
Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge said: “Young people often experience multiple mental health disorders, beginning in adolescence and continuing – and often transforming – into adult life. This suggests that there’s a common brain mechanism that could explain the onset of these mental health disorders during this critical time of brain development.”
In the study, the researchers say they have identified a characteristic pattern of brain activity among these adolescents, which they have termed the ‘neuropsychopathological factor’, or NP factor for short.
The team examined data from 1,750 adolescents, aged 14 years, from the IMAGEN cohort, a European research project examining how biological, psychological, and environmental factors during adolescence may influence brain development and mental health. In particular, they examined imaging data from brain scans taken while participants took part in cognitive tasks, looking for patterns of brain connectivity – in other words, how different regions of the brain communicate with each other.
Adolescents who experienced mental health problems – regardless of whether their disorder was one of internalising or externalising symptoms, or whether they experienced multiple disorders – showed similar patterns of brain activity. These patterns – the NP factor – were largely apparent in the frontal lobes, the area at the front of the brain responsible for executive function which, among other functions, controls flexible thinking, self-control and emotional behaviour.
The researchers confirmed their findings by replicating them in 1799 participants from the ABCD Study in the USA, a long-term study of brain development and child health, and by studying patients who had received psychiatric diagnoses.
When the team looked at genetic data from the IMAGEN cohort, they found that the NP factor was strongest in individuals who carried a particular variant of the gene IGSF11 that has been previously associated with multiple mental health disorders. This gene is known to play an important role in synaptic pruning, a process whereby unnecessary brain connections – synapses – are discarded. Problems with pruning may particularly affect the frontal lobes, since these regions are the last brain areas to complete development in adolescents and young adults.
Dr Tianye Jia from the Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China and the Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK said: “As we grow up, our brains make more and more connections. This is a normal part of our development. But too many connections risk making the brain inefficient. Synaptic pruning helps ensure that brain activity doesn’t get drowned out in ‘white noise’.
“Our research suggests that when this important pruning process is disrupted, it affects how brain regions talk to each other. As this impact is seen most in the frontal lobes, this then has implications for mental health.”
The researchers say that the discovery of the NP factor could help identify those young people at greatest risk of compounding mental health problems.
Professor Jianfeng Feng from Fudan University in Shanghai, China, and the University of Warwick, UK, said: “We know that many mental health disorders begin in adolescence and that individuals who develop one disorder are at increased risk of developing other disorders, too. By examining brain activity and looking for this NP factor, we might be able to detect those at greatest risk sooner, offering us more opportunity to intervene and reduce this risk.”
