Research paperDepression and anxiety among chronic pain patients receiving prescription opioids and medical marijuana
Introduction
Chronic pain has been reported to affect at least 8% of the population in developed countries annually (Andrew et al., 2014). The total healthcare cost associated with pain in the US has been estimated at $261 to $300 billion per year (Gaskin and Richard, 2012), with average annual costs of pain patients estimated to be three times higher than of individuals without chronic pain (Berger et al., 2004). Chronic pain has been associated with a significant decrease in daily activities, occupational productivity and quality of life (Breivik et al., 2006, Patel et al., 2012, Smith et al., 2007). In addition, individuals suffering from chronic pain have high rates of comorbid psychiatric disorders which may further reduce activity and quality of life, including drug and alcohol use disorders, mood and anxiety disorders (Demyttenaere et al., 2007, Feingold et al., 2016a, Gerrits et al., 2014, Gerrits et al., 2012).
The association between chronic pain, depression and anxiety has gained particular attention due to high rates of co-morbidity (Dersh et al., 2002). Up to 54% of pain patients have been reported to suffer from co-morbid depression, and up to 50% have been reported to suffer from anxiety, with particularly high rates of Generalized Anxiety Disorder (Gadermann et al., 2012), specific phobia and panic disorder (Banks and Kerns, 1996, Dersh et al., 2002, Knaster et al., 2012, McWilliams et al., 2003). The causal association between depression and anxiety and chronic pain is yet unclear, with findings supporting both an antecedent and consequent association (Magni et al., 1994, Polatin et al., 1993).
Prescription opioids are one of the most common modalities for the pharmacological treatment of pain, and have proven useful for the treatment of acute pain (Moore and McQuay, 1997, Shang and Gan, 2003) and pain related to cancer (Carr et al., 2004). In addition, these medications have been increasingly used for the treatment of chronic nonmalignant pain (Compton and Volkow, 2006). However, in the past two decades there is gradual awareness of public health risks associated with the increase in prescriptions to opioids (such as risks of diversion, overdose and addiction (Volkow and McLellan, 2016)) warranting the search for alternatives means for treatment of chronic pain. Medical marijuana (MM) has been used widely for pain control in the US and in several countries worldwide, becoming increasingly popular as a potential alternative to prescription opioids for the treatment of chronic pain (Hill, 2015, Jensen et al., 2015). However, due to great variability in the legal status of MM in different countries, data pertaining to the sociodemographic and clinical characteristics of chronic pain patients receiving MM compared to those receiving prescription opioids is scarce (Hall and Weier, 2015). Specifically, there is a lack of data regarding rates of co-occurring depression and anxiety among individuals receiving these two treatments. This may be important as the use of opioids and marijuana may in itself differentially affect levels of depression, anxiety and perceived pain.
The aim of the present study is to explore rates of depression and anxiety among individual receiving treatment for chronic pain, comparing individuals receiving prescription opioids and those receiving MM.
Section snippets
Sample
Subjects for this study were recruited during a 6-month period in two large pain centers in Israel. Patients treated for chronic pain (i.e. pain lasting for more than three months (Elliott et al., 1999)) were approached for recruitment for the study. The response rate was 57%, encompassing a total of 890 participants. Patients participating in the study were not reimbursed for their participation and all subjects were required to sign an informed consent form prior to participation, which was
Sociodemographic and clinical data
The following data was collected from each participant using self-administered questionnaires:
- 1.
Socio-demographic data, including sex, age country of birth, type of residence (urban/rural), years of education, employment status, eligibility for disability allowance, marital status and number of children.
- 2.
Medical history: participants were asked regarding lifetime diagnoses of common medical conditions including hypertension, liver disease, heart disease, ulcer or duodenum disease, migraine,
Results
Among participants, 474 (59%) were treated with prescription opioids exclusively, 329 (41%) were treated with MM exclusively and 77 (8.6%) received both. The remaining 10 subjects, receiving neither prescription opioids nor MM were excluded from analyses in this study. The proportion of women was significantly higher in the OP group compared to the MM group (p<0.01) group, as was the proportion of patients receiving a disability allowance (p<0.01) (Table 1). Patients in the OP group were more
Discussion
In this study we explored rates of depression and anxiety among patients receiving treatment for chronic pain, comparing patients receiving prescription opioids and those receiving MM. Though no differences were found in rates of common medical conditions associated with pain and in rates of co-occurring substance use, patients in the OP group had higher rates of depression and anxiety compared to those in the MM group. After controlling for potentially confounding factors, patients in the OP
Acknowledgements
None.
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