Chronic pain, opioid misuse contribute to anhedonia
Patients with chronic pain and those with reported misuse of opioid medications exhibit reduced hedonic capacity compared with healthy individuals, suggesting that both chronic pain and opioid misuse have a hand in anhedonia, according to a study.
The study included three cohorts of chronic pain patients (n=432) who had received prescription opioid analgesics for >90 days, another cohort (n=56) of chronic pain patients treated with nonopioid medications, and 2,664 psychiatrically healthy participants.
All participants underwent the following assessments: Snaith–Hamilton Pleasure Scale (SHAPS), measures of opioid use, pain severity and depression, and the Current Opioid Misuse Measure (COMM).
Compared with healthy controls, chronic pain patients showed higher levels of anhedonia, with about 25 percent of them scoring above the standard anhedonia cutoff. This difference could not be attributed to depression levels, which explained only <25 percent of the variance in anhedonia scores.
Furthermore, anhedonia was not associated with opioid use duration, dose, or pain severity alone.
However, anhedonia symptoms were significantly greater among patients described as opioid misusers vs non-misusers. This association remained significant despite adjustments for individual differences in pain severity, depression, opioid dose, and duration of opioid treatment.
In literature, mechanisms linking chronic pain and anhedonia include disrupted endogenous opioid signalling, changes to mesolimbic signalling, prefrontal areas, or the interaction between these circuits, and changes in attention.