Criterion Validity of the Diagnostic Criteria for Psychosomatic Research in Patients with Morbid Obesity
Authors: Francesca Venditti, Fiammetta Cosci, Olivia Bernini, Carmen Berrocal
Journal: Psychotherapy and Psychosomatics (2013)

The Diagnostic Criteria for Psychosomatic Research (DCPR) consist of 12 clusters representing different abnormal illness behaviour and psychosocial factors with prognostic and therapeutic implications in medical settings [1]. The presence of a DCPR diagnosis is related to higher levels of distress, a high prevalence of allostatic overload syndrome [2], greater impairment of mental health, lower psychological well-being (PWB) and quality of life, and a more serious disease condition [3]. Furthermore, a higher number of DCPR diagnoses are associated with a lower quality of life and PWB in dermatological and cancer conditions [4,5].This is the first study exploring the relationships of DCPR diagnoses with PWB and ICD-10 mental disorders in patients with morbid obesity. Obesity is a major worldwide health concern, given the substantial health and economic burden associated with excess weight [6]. The DCPR could enhance the decision-making process aimed at managing obesity by providing important clinical information that DSM or ICD-10 does not capture [1]. We predicted that DCPR diagnoses would be more frequent in obese patients than in normal weight controls and that the former would show lower levels of PWB. We also expected that the DCPR diagnoses would be independent of the ICD-10 mental disorders in obese patients and that a higher number of DCPR syndromes would be related to lower PWB.The cases were 39 outpatients (29 females; age: 35.8 ± 11.8 years) with morbid obesity (BMI: 45.7 ± 10.3; weight: 127 ± 28.5 kg) consecutively referred to the Community Mental Health Centre in the area of Malaga (Spain) for psychological assessment over a 12-month period before bariatric surgery. The controls were 36 normal weight subjects (25 females; age: 30.7 ± 10.4 years; BMI: 23.3 ± 3.2; weight: 64.8 ± 12.5 kg) recruited from students at the University of Malaga and from the general population via the 'snowball' technique. The groups did not significantly differ in respect of gender or employment status (cases: 46.2% employed; controls: 60% employed). The controls were significantly younger than the patients (t = -1.957, p < 0.05). A higher percentage of the controls (80.6%), if compared to the cases (56.4%), had at least high-school education (χ2 = 24.525, p < 0.001).Participants underwent the Structured Interview for DCPR [7] and completed the 54-item version of the PWB questionnaire [8]. Current ICD-10 mental disorders were also explored in obese patients by means of a structured interview [9].The percentage of subjects with at least one DCPR diagnosis was similar across the groups (cases: 92%; controls: 89%). Health Anxiety and Demoralization occurred, respectively, in 21 and 23% of the patients, while they did not occur among the controls (χ2 = 9.441, p < 0.002). Illness Denial (cases: 80%; controls: 72%) and Alexithymia (33% in both groups) were also frequently but similarly represented in the two groups. The remaining diagnostic clusters were poorly and similarly represented in both groups. A total of 13 patients (33%) fulfilled the DCPR criteria for one diagnosis, 13 (33%) for two, and 10 (26%) for three or more DCPR diagnoses. Patients with more than two DCPR diagnoses were younger (27.6 ± 6.1 years) than those in the other subgroups (one DCPR diagnosis: 40.7 ± 12.9 years; two DCPR diagnoses: 38.8 ± 11.7 years; F = 4.490, p < 0.01). The groups did not differ with regard to the remaining sociodemographic characteristics.The patients yielded lower scores than the controls in several PWB dimensions. The patients with more than two DCPR diagnoses showed lower Autonomy and Self-Acceptance than those with one or two DCPR diagnoses (table 1).Three (7.7%) patients received neither a DCPR nor an ICD-10 diagnosis. A total of 14 (35.9%) patients had one ICD-10 diagnosis. The most frequent ICD-10 diagnoses were Mixed Anxiety-Depressive Disorder (15.4%), Obsessive-Compulsive Disorder (5.1%) and Borderline Personality Disorder (5.1%). Only 1 patient (2.6%) met the criteria for Binge Eating Disorder. All patients with an ICD-10 diagnosis also met the criteria for at least one DCPR diagnosis.The percentage of patients presenting with an ICD-10 disorder was similar across the DCPR subgroups (4 patients in the two-DCPR group and 5 patients each in the other DCPR groups; χ2 = 2.730, p = 0.435). Interestingly, 22 patients (56.4%) had at least one DCPR diagnosis even though they had no ICD-10 mental disorder. The main DCPR diagnoses in these patients were Illness Denial (51.3%), Alexithymia (15.4%), Health Anxiety and Demoralization (12.8% each). This is the first study identifying specific DCPR syndromes which could affect obesity: Health Anxiety and Demoralization were more frequent in the obese patients than in the controls. Our findings suggest that the experience of morbid obesity may trigger feelings of hopelessness and health-related concerns, which, in turn, may hamper efforts to manage excess weight. Illness Denial and Alexithymia emerged as the most frequent diagnoses and occurred in a similar percentage in both groups. The results suggest that these syndromes are not specifically linked to obesity and that they also deserve attention in general population samples. Indeed, both Illness Denial and Alexithymia may reflect a generalized avoidant coping style which may inhibit the adoption of healthy lifestyles [1,10].The cases showed lower PWB than the controls and a higher number of DCPR diagnoses were associated with lower Autonomy and Self-Acceptance. These results are consistent with previous research [4,5] and support the criterion validity of the DCPR in obesity.Compared to the controls, a higher percentage of the patients had at least one DCPR diagnosis but no ICD-10 disorders. This suggests that, also in the field of obesity, the DCPR capture clinical phenomena outside the range of the current nosological classifications [1,3]. Expanding the assessment of obese patients to the DCPR syndromes could provide the clinicians with a broader characterization of patients' functioning and psychological response to medical illness. Obese patients might also benefit from specific therapeutic strategies to cope with those psychosocial variables and abnormal illness behaviour which affect PWB.Due to the preliminary nature of our study, several shortcomings limit the generalization of our findings, including the limited sample size, the cross-sectional design and the recruitment method in the control group. Future research aimed at exploring the validity of the DCPR to longitudinally predict the important outcome criteria in obese patients (e.g., weight loss) is warranted.