Chronic Pain, Opioid Dispensing, and Mental Health: A Complex and Potentially Dangerous Combination
August 6, 2020Individuals with bipolar disorder, depression, and schizophrenia – in addition to chronic pain – may respond differently to opioid therapy.By Avery Hurt
Chronic pain prevalence, opioid use – and related deaths and disorders – continue to plague clinicians and policymakers as they struggle to find solutions for safe and adequate pain management to those suffering. The challenge is made more complex by mental illness, specifically depression and bipolar disorder, which impact a high percentage of those living with chronic pain conditions.
In fact, a 2016 study published in Pain reported that around 60% of the subjects studied (n = 1,204) with chronic disabling pain disorders experienced depression and 33% met criteria for severe depression.1 Of note, chronic non-cancer pain is reportedly less common among those with schizophrenia, although there have been a dearth of inconclusive studies on treatment patterns in this population. PPM addressed this issue in a prior paper.
People with mental health disorders are more likely to receive long-term opioids at a higher daily dose and with more days of medication prescribed than are those patients without mental illness. (Image: iStock)
Perhaps not surprisingly, this already vulnerable population is also more likely to receive long-term opioids at a higher daily dose and with more days of medication prescribed than are those patients without mental illness.1
To get more clarity on the role that opioids play in pain management for patients with mental illness, researchers at the Georgia State University School of Public Health investigated whether individuals with major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia are more likely to be diagnosed with chronic pain disorder, and if so how likely they are to be given opioid medications. The resulting study was published in BMC Psychiatry earlier this year.2
Methods and Controls
Researchers used EMR data from 13 mental health research network sites to identify individuals diagnosed with MDD, BD, schizophrenia/schizoaffective disorder. These diagnoses had been documented at least twice by a mental healthcare provider. The subjects were then matched to controls based on age, sex, and Medicare status. The control population had no documented mental illness. Only subjects between 18 and 70 years old were included in the analysis.
Some patients had more than one mental health diagnosis across the categories. In those cases, the diagnoses were categorized hierarchically, in the following order: schizophrenia/schizoaffective disorder, MDD, BD. Thus, a patient with both schizophrenia and MDD would be placed in the schizophrenia group, and so on.
In addition, to be eligible for the study, individuals had to have had continuous healthcare coverage throughout the period of the analysis (allowing for small administrative gaps due to data processing when, for example, a patient changed jobs). Individuals with any type of cancer diagnosis were excluded. Controls were similarly identified.
Once the subjects and controls were established, the team extracted from the EMR records diagnoses of chronic pain conditions including: musculoskeletal pain, arthritis, fibromyalgia, headache, temporomandibular pain, abdominal and bowel pain, chest pain, urogenital and menstrual pain, pain due to fractures, contusions, and sprains or strains. Specific painful conditions, such as sickle cell disease, complex regional pain syndrome, systemic lupus erythematosus, spinal cord injury, and neuropathic pain were also included.
Opioid prescriptions and dispensing were extracted for the matched samples, noting chronic opioid use. The researchers also looked at socioeconomic and clinical characteristics of those included in the study. The final number of subjects was 377,927.
Depression and Bipolar Findings
The results confirmed earlier data that individuals with MDD or BD are significantly more likely to be diagnosed with chronic non-cancer pain than controls and found that this population was more than two times more likely to receive prescriptions for opioid medication. The study’s authors suggested that this might be because these patients are more likely to present with high pain severity. However, they pointed out that the relationship between depression and opioid use can be complex and bidirectional, and that chronic opioid use may increase the risk of depression.2
“Individuals who are at risk for developing opioid-related problems also being the ones who are likely to be prescribed opioids is definitely concerning,” Ashli Owen Smith, PhD, lead author of the study and assistant professor of Health Policy and Behavioral Sciences at Georgia State University’s School of Public Health, told PPM.
However, Dr. Owen-Smith noted that this finding is not necessarily a matter of physicians not following best practices regarding opioids. “If you have a patient in front of you who’s reporting debilitating pain that’s interfering with quality of life, providers want to help those patients. They want to provide appropriate pain management.” But she added, “We as a medical community have not historically had a lot of good options for patients with non-malignant chronic pain, whether they have mental illness or not.”
Those options may be changing, but slowly. “We’re learning more about non-pharmaceutical interventions. There are a range of behavioral interventions, for example things like tai chi, mindfulness-based interventions, acupuncture, chiropractic care,” said Dr. Owen-Smith, “but the science is just now being able to document and assess that rigorously.”
Schizophrenia Findings Differ Among Chronic Pain Populations
The team’s record review found an entirely different problem for patients with schizophrenia and schizoaffective disorder. These patients were significantly less likely to be diagnosed with chronic pain as compared to controls. The reason for this distinction was not clear, but the researchers offered several potential explanations.
To start, there is some evidence that people with schizophrenia are less sensitive to pain and that antipsychotics may have a mild analgesic effect (although other evidence disputes this).1 It’s also possible that patients with schizophrenia are unable or unwilling to adequately express their pain. On the provider side, it could be that providers may not have enough time during a patient encounter to ask about potential pain issues or may be preoccupied with other goals during the encounter.
“We need more research in this area to understand what that dynamic is with providers around discussing pain, interpreting pain, and treating it,” said Dr. Owen-Smith. “If the problem is that patients with schizophrenia are not talking about pain with their doctors, perhaps one solution is for doctors to more mindfully ask about pain, proactively take time to assess that and to have a conversation about it.”
Overall, Dr. Owen-Smith’s team recommended that clinicians take a very conservative approach to opioid prescribing in patients with depression or bipolar disorder. “Our understanding of best practices around opioid prescribing is really shifting,” she noted, “so I think generally most providers are already being very conservative about opioid prescribing for chronic conditions, but given our findings and what we know about mental illness as a risk factor, opioid prescribing [in patients with mental illness] really warrants additional reflection.”