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Deep brain stimulation effective for severe OCD

Deep brain stimulation can halve the symptoms of severe obsessive–compulsive disorder (OCD), according to a pooled data analysis of the available evidence, published in the Journal of Neurology, Neurosurgery and Psychiatry. The analysis found that two‐thirds of those affected experienced substantial improvement within two years. OCD is characterised by intrusive and persistent obsessive thoughts along with dysfunctional and ritualised behaviours. It is thought to affect up to 3% of people. Drugs and cognitive behaviour therapy can be very effective, but in approximately 1 in 10 cases, such approaches do not work. The researchers systematically reviewed and pooled the results of 34 clinical trials published between 2005 and 2021, to critically assess how well deep brain stimulation alleviates OCD and associated depressive symptoms in adults. The 34 studies included 352 adults with an average age of 40 years, and severe to extreme OCD, the symptoms of which had not improved despite treatment. In 23 of the studies, participants were required to have had persistent symptoms for five or more years before consideration for surgery. Of the remaining 11 studies, one had a requirement of more than a decade of symptoms and two or more years of failed treatment; another required at least one year of failed treatment; and five did not specify any requirements. On average, symptoms had persisted for 24 years. Coexisting mental health issues were reported in 23 studies and included major depression (over half of participants), anxiety disorder, and personality disorder. The average monitoring period after deep brain stimulation was two years. The final pooled data analysis, which included 31 studies involving 345 participants, showed that deep brain stimulation reduced symptoms by 47%, and two‐thirds of participants experienced substantial improvement within the monitoring period. Secondary analysis revealed a reduction in reported depressive symptoms, with complete resolution in nearly half of participants and partial response in a further 16%. Twenty‐four studies reported complete data on serious side effects, including hardware‐related complications, infections, seizures, suicide attempts, stroke, and the development of new obsessions associated with stimulation. Overall, 78 participants experienced at least one serious side effect.

https://jnnp.bmj.com/content/early/2022/07/31/jnnp‐2021‐328738

Exposure to air pollution may worsen autism‐related hospital admissions in children

Children with autism may be at heightened risk of being admitted to hospital if they are exposed to air pollution for relatively brief periods, with boys more at risk than girls, suggests research published in BMJ Open. Admissions for issues such as hyperactivity, aggression or self‐injury might be prevented by minimising such children’s exposure to air pollution. It is believed that short term exposure to air pollution (days to weeks) can induce systemic inflammation and neuroinflammation, potentially increasing the risk of hospital admission in people with autism. Previous air pollution studies have focused on the association between long term exposure to air pollution (months to years) during pregnancy and early postnatal period, and autism spectrum disorder (ASD) development among children. The researchers drew on official Korean government data on daily hospital admissions for autism among children aged 5–14years between 2011 and 2015. They collected data on national daily levels of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂) and ozone (O₃) in each of the 16 regions in the Republic of Korea for up to six days. The average daily number of hospital admissions for autism during the study period was 8.5 for children with autism and was much higher for boys (seven) than for girls (1.6). A 10μg/m³ increase in PM_2.5 levels was associated with a 17% higher risk of hospital admission for autism, and a 10 parts per billion increase in NO₂ and O₃ was associated with a 9% and 3% higher risk, respectively. The researchers calculated that exposure to these pollutants was associated with a one‐quartile increase (8.2μg/m³ for PM_2.5; 6.7 parts per billion for NO₂, and 11.3 parts per billion for O₃), which corresponds to a 29% higher risk of hospital admission for autism, with NO₂ exerting the strongest effects. The researchers acknowledge that they used regional air pollution levels rather than individual ones, which could have affected their findings, and that children with autism with mild symptoms might be less likely to receive psychiatric treatment and so might not have been included.

https://bmjopen.bmj.com/content/12/9/e058286