Objectives. Clinical practice and recent literature indicate that pain is experienced not infrequently in depression. Origins of such pains are unknown, and in particular it is not known whether the pain perception threshold (PPT) may be of importance in this respect. The aims of the study were: (1) to assess PPT values during a depressive episode and on amelioration in the study group and to compare their PPTs with these in the control group, (2) to analyze the relationship between pain perception in depression and pain perception threshold.
Method. The SG consisted of 60 hospitalized patients with the diagnosis of a depressive episode in the course of either recurrent depressive disorder or bipolar affective disorder. The CG included 30 healthy volunteers. In the clinical study PPTs were measured twice using a mechanical algometer (on admission and when an amelioration was attained). Other instruments included: the Hamilton Depression Scale, the Pain Questionnaire by Melzack, and a verbal rating scale for pain assessment.
Results. Pains varying in character, location and duration were reported by 75% of the study group. The mean PPTs were: 4.85 kg in the group under study and 4.78 in the controls (difference not significant); 4.81 kg in the subgroup with pain (75% of the SG) and 4.96 kg in the pain-free subgroup (25% of the SG) (difference not significant). In the subgroup of patients with depressive episode amelioration or remission the mean PPT was 4.06 - the difference was significant as compared to their PPT on admission or to that in the CG (p<0.001).
Conclusions. In the sample studied the mean pain perception threshold was slightly higher, but not significantly different, in the study group than in the controls. The PPT decreased significantly on amelioration of the patients' mental state (their PPT was even lower than that in the CG). No relationship was found between PPT value and the type of depressive episodes - in the course of recurrent depressive or bipolar affective disease.