Anxiety, depression, and anger in the borderland of chronic pain

Chronic pain is a long-lasting burdensome condition. Comorbid psychological symptoms are common in chronic pain patients and they tend to worsen the treatment outcome. The aim of this cross-sectional study was to assess the prevalence of psychiatric comorbidity in chronic pain patients and to assess the associations between chronic pain, anxiety, anger, and depression. The study participants in the study were one hundred consecutive chronic pain patients referred to the Meilahti Pain Clinic of Helsinki University Hospital. The subjects were interviewed with the Structured Clinical Interview for DSM-IV for Axis I disorders (SCID-I). In addition self-report questionnaires were used in the assessment. Most (75%) patients had at least one lifetime mental disorder. The prevalence of major depressive disorder (MDD) was 37% and of a specific anxiety disorder 25% over the past 12 months. The psychiatric comorbidity was associated with increased pain intensity, measured by Visual Analogue Scale (VAS). The majority (77%) of the anxiety disorders had their onset before the onset of pain, whereas only 37% of the mood disorders preceded pain onset. The Harm Avoidance (HA) scale of the Temperament and Character Inventory (TCI) of Cloninger was associated with pain-related anxiety measured with Pain Anxiety Symptom Scale-20. The pain intensity influenced the strength of the association between the Harm Avoidance HA4 subscale and pain-related anxiety. Higher pain intensity was associated with stronger association between the variables. Likewise, pain intensity influenced the association between anger management and depression. A tendency to inhibit angry feelings was associated the somatic and physical symptoms of depression, measured by a two-factor model of the Beck Depression Inventory (BDI). The association was stronger in patients with higher pain intensity. Chronic pain patients with current MDD scored higher in both the somatic and cognitive-emotional subscales of the BDI compared with those without MDD. However, the somatic-physical-related items were more strongly associated with the diagnosis of MDD. Psychiatric disorders are common in chronic pain patients. Because of their influence on the chronic pain treatment and outcome, their thorough assessment is important. The linking mechanisms between chronic pain and the psychiatric disorders and symptoms are complicated and there is an overlap between the constructs. Clear boundaries between pain, anxiety and depression can be difficult to draw, which can be a reflection of the common background mechanisms such as common neural circuits and neurotransmitters.