Long-term use of painkillers before the age of 25 years could have an impact on substance misuse, mental illness, and prescription opioid use later in life, according to a new study.
A research team led by the University of Liverpool and St George's, University of London, noted that around a quarter of children are affected by chronic and recurrent pain (defined as lasting more than 3 months), and that 8% report intense and frequent pain.
However most previous research investigating chronic pain and painkiller use had focussed on adults. Also, while it was known that both chronic pain and painkilling medications could cause long-term harm, most studies assessed only one or the other, leaving it hard to know which causes the most impact.
To plug this evidence gap, the researchers undertook a cohort study to investigate the scale of chronic pain and long-term analgesic use in children and young people, and to assess the effects on substance use and mental health later in adulthood. The calculated risk of mental illness was a composite outcome including anxiety, depression, bipolar affective disorder, schizophrenia, referral to mental health services, eating disorders, self-harm or suicide, and personality disorders.
They used anonymised electronic health records from a UK medical research database to identify individuals aged 2-24 years with either a diagnostic code indicating chronic pain (diagnosis-exposed), repeat prescriptions for common painkilling medications (prescription-exposed), or both.
The whole cohort included 853,625 individuals, of whom 146,431 were diagnosis-exposed (115,101) or prescription-exposed (20,298), or both (11,032). The remaining 707,194 people served as comparators when followup began at the age of 25 years.
Over an average 5-year follow up, 11,644 people had a substance misuse event, 143,838 had a mental health problem, and 77,337 had received at least one opioid prescription.
Increased Risk of Mental Illness After Chronic Pain Diagnosis
The results, published in The Lancet Regional Health – Europe, showed that after adjustment for gender, deprivation, smoking, alcohol, BMI, year of birth, prior mental illness, and prior substance misuse, people who had chronic pain recorded under age 25 were 29% more likely than the comparator group to be diagnosed with a mental illness in adulthood.
Those who had chronic pain and were also given prescription painkillers were 46% more likely to develop adult mental illness, and 82% more likely to succumb to substance misuse. The latter group were also more likely to have received prescription opioids in adulthood.
The increased risk of substance misuse was not found in those with a chronic pain diagnostic code alone. "This suggests that, specifically, receipt of a repeat prescription for an analgesic medicine before the age of 24 is associated with substance misuse in adulthood," the researchers said.
In addition, children and young people with intellectual disability or autism spectrum disorder were "overrepresented" among participants receiving repeat painkiller prescriptions in the absence of a chronic pain diagnosis. "This may indicate overprescribing in this already vulnerable group," the researchers stated.
A study by the University of Cambridge last year showed that people with autism had "worryingly high" rates of lifetime mental health conditions including anorexia, anxiety, ADHD, bipolar disorder, depression, insomnia, OCD, panic disorders, personality disorders, PTSD, SAD, and self-harm.
"Risk of Life-long Adverse Outcomes"
The researchers concluded: "Young people with chronic pain are at risk of life-long adverse outcomes, and the way pain is managed while childhood and adolescent neurodevelopment is ongoing may have important implications for these outcomes."
They commented that while it is "essential to avoid the harms of undertreating pain in children and young people", due consideration should be given to the risks posed by analgesics. "Early recognition of chronic pain in children and young people, and utilising nonpharmacological management options, may help minimise overprescribing and long-term reliance on dependence-forming-drugs," they advised.
Lead author Dr Andrew Lambarth, academic clinical fellow at St George's, said: "It's clear that chronic pain management in young people needs to be optimised. We know undertreating pain can cause harm in both the short- and long-term, but it's also essential to avoid overreliance on medicines that could lead to dependence on prescription or nonprescription drugs in later life."
Professor Reecha Sofat, Breckenridge chair of clinical pharmacology and therapeutics at the University of Liverpool, said the trends were "concerning" as regular use of painkillers in youth might lead to "unintentional overreliance on pain medication in adult life". Referral to specialised pain services for more targeted support was vital in "revamping pain management practice", she said.
The study was funded by UCLH Charity, UKRI, Versus Arthritis, and the Wellcome Trust.