Alexithymia as a Moderator of Treatment Outcomes in a Randomized Controlled Trial on Brief Psychodynamic Interpersonal Psychotherapy for Patients with Multisomatoform Disorder
ly, during the first phase the therapeutic relationship was established, and the legitimacy of bodily complaints was underscored; second, the main phase targeted the patient's behavior, emotions and interpersonal experiences, and their associations with the symptoms; third, termination issues were discussed. EMC comprised 3 sessions (approx. 30 min at 6 week intervals) of education and counseling based on evidence based guidelines for the treatment of somatoform disorders/functional somatic syndromes in primary and somatic specialist care [9] the therapists discussed an explanatory model of the development and maintenance of the symptoms including advice on symptom management, specific pharmacological/psychotherapeutic treatments, and health care use. The patients were assessed before treatment (t1) 3 months after t1 (t2) and 9 months after t2 (t3) 180 patients took part in the t2 assessment (PIT: 95; EMC: 85) and 184 patients participated in the t3 assessment (PIT: 96; EMC: 88) Of the several questionnaires that were administered to the patients [7] the Toronto Alexithymia Scale (TAS 20) the physical component summary (PCS) of the SF 36 Health Survey as well as the mental component summary (MCS) of the SF 36 Health Survey were used in the present study. The PCS and the MCS were both assessed at t1, t2, and t3 and functioned as the outcome measures; PCS assesses physical quality of life and MCS emotional quality of life. The TAS 20 was assessed at t1, and the TAS 20 global score was used to operationalize the potential moderator alexithymia. Multilevel models for discontinuous change with full maximum likelihood estimation and an unstructured variance covariance matrix were performed to investigate alexithymia as a moderator of outcomes. The TAS 20 scores were dichotomized for these analyses by median split. In our sample, the scores of the TAS 20 ranged from 22 to 75 (mean 47.85; SD 11.74) and the median value of 48 is comparable to the median found in the general population of Germany [10] Patients with TAS 20 scores of at least 48 median) were defined to have higher alexithymia, and patients with TAS 20 scores below 48 <median) were classified as patients with lower alexithymia. The two treatment conditions did not significantly differ in the ratio of patients with higher/lower alexithymia. The first multilevel model explored whether alexithymia moderates PCS outcomes either from t1 to t2 or from t1 to t3. Levels of alexithymia had no significant impact at all on the PCS. Figure 1 illustrates the estimates of this multilevel model. The second multilevel model evaluated whether alexithymia moderates MCS outcomes either from t1 to t2 or from t1 to t3 and revealed the following results: in EMC, patients with higher alexithymia improved significantly less on the MCS than patients with lower alexithymia from t1 to t2 [t(197.31) 1.98; p 0.05] but Personalized medicine addresses the question of which treatment works for whom [1] For patients with alexithymia, no evidence based treatments exist [2] While several studies investigated whether alexithymia predicts outcomes and found that alexithymia leads to a less favorable outcome in psychodynamically oriented but not in cognitive behavioral psychotherapy [3] only very few comparative studies investigated alexithymia as a moderator of outcomes between psychotherapies [4, 5] Since these past moderation studies did not focus on patients with somatoform disorders and alexithymia has been described as a central construct in the context of somatization [6] the present study investigated alexithymia as a moderator of treatment outcomes in a multicenter randomized controlled trial (RCT) on brief psychodynamic interpersonal psychotherapy (PIT) versus enhanced medical care (EMC) for patients with multisomatoform disorders. The study, whose methods and main outcomes are described in detail elsewhere [7] was approved by the ethics committees of the 6 participating sites and registered as a trial (ISRCTN23215121) The RCT included 211 patients (PIT: 107 patients; EMC: 104 patients) meeting the diagnostic criteria for multisomatoform disorder with at least one symptom of pain in order to define a criterion resulting in a clinically relevant and more homogeneous sample (a modified version of the Structured Clinical Interview for DSM IV was used) A multisomatoform disorder diagnosis requires a minimum of 3 current, functionally disabling somatoform symptoms not sufficiently explained by an organic disease or another mental disorder and a history of somatoform symptoms on at least half of the days over at least 2 years, resulting in health care use. PIT comprised 12 weekly sessions (first session: up to 90 min; all other sessions: approx. 45 min) consisting of 3 phases [8] BriefReceived: June 9, 2016 Accepted: July 9, 2016 Published online: November 25, 2016
Psychotherapy and Psychosomatics