Physical pain highly prevalent among patients with psychiatric illness

Most patients with psychiatric illness sustain physical pain, and they perceive pain differently, according to a Singapore study.

In a cohort of 290 outpatients diagnosed with schizophrenia spectrum disorder, depression, or anxiety, the overall prevalence of pain—which was measured using the Brief Pain Inventory (BPI)—was 73.3 percent, and 37.6 percent had painful chronic conditions, according to a group of investigators from the Institute of Mental Health in Singapore. [Pain Res Manag 2022;doi:10.1155/2022/1825132]

They also found that patients from the three psychiatric groups rated average physical pain disparately. For example, the optimal cutoff point for average pain was 4–6 (mild pain 1–4, moderate pain 4–6, severe pain 7–10) among those with anxiety and depressive disorders as opposed to 3–5 (mild pain 1–3, moderate pain 4–5, severe pain 6–10) among those with schizophrenia spectrum disorders.

In accordance with the cutoff point-based classification in the overall sample, which followed that in the anxiety and depressive disorder groups, 38.5 percent of the patients had mild pain, 22.9 percent had moderate pain, and 11.8 percent had severe pain. Compared with those who reported experiencing no pain, those who had severe pain tended to be older (p≤0.006), not married (p≤0.025), and at high risk of obesity (p≤0.030). Patients with mild pain were also more likely to be of older age (p≤0.021).

Moreover, moderate and severe pain were strongly linked with higher Beck's Anxiety Inventory (BAI) scores. Severe pain, on the other hand, was significantly associated with an increased risk of obesity.

“To our knowledge, this is the first study that has determined the optimal cutoff points that categorize BPI pain scores as mild, moderate, and severe pain, based on patient’s ratings of average physical pain and to provide optimal cutoff points for depressive, anxiety, and schizophrenia spectrum disorders among psychiatric outpatients,” the investigators said.

They added that the finding of different cutoff points for chronic physical pain for patients with schizophrenia spectrum, anxiety, and depressive disorders was novel.

The lower cutoff points for an average pain intensity among patients with schizophrenia spectrum disorders in the present study may be attributed to psychotic analgesia that occurs due to the presence of severe negative symptoms and cognitive impairment. This, according to the investigators, often leads to a deficit in identification and categorization of pain, as well as reduced level of emotional awareness to painful stimuli that results in lower readiness to verbalize pain. [Neuropsychiatr Dis Treat 2015;11:2023-2031].

“On the other hand, maladaptive coping skills among patients with anxiety disorders may lead to self-perpetuating cycle that stimulates and maintains increased emotional reactivity, impairing the ability to modulate pain. This may further amplify fear and severity of anxiety symptoms resulting in heightened attention towards painful stimuli leading to increased pain intensity,” the investigators explained. [Psychosom Med 2002;64:773-786; Depress Anxiety 2009;26:888-901]

“Similarly, an interaction between depressive disorder and pain, known as depression-pain dyad or depression pain syndrome, imply that these conditions often co-exist and exacerbate one another, as they share analogous pathophysiological pathways and neurotransmitters,” they added.

The investigators were positive that the cutoff points for pain intensity established in the current study could be used as a screening instrument to detect pain, and the difference in these cutoff points for different conditions should be considered when measuring pain among patients with psychiatric illness. They pointed out that screening for physical pain has important clinical implications, as the presence of both psychiatric illnesses and physical pain significantly influences the course of the former condition and worsens its prognosis.

Overall, improving the knowledge on the correlates and comorbidities of physical pain can aid in early identification and use of prophylactic strategies or intervention techniques, as well as assist in formulating guidelines for pain management in the psychiatric population, the investigators said.

“This could be achieved by engaging mental health clinicians in addressing pain treatment as they are in best position for assessment of pain, introduce and initiate customised treatment plans, suggest behavioural treatment according to patient’s condition, as well as encourage them to participate in self-management and physical activities. This in turn, would ease individual suffering, lessen societal expenses, and lower the global burden associated with chronic pain conditions,” they added.