Objective: The aim of this study was to estimate the incidence of treatment-emergent mania/hypomania (TEMH) and to describe the clinical characteristics of patients with major depression experiencing this event during treatment with a selective serotonin reuptake inhibitor (SSRI) and/or interpersonal psychotherapy (IPT).
Methods: Following an algorithm-based protocol, 344 patients with major depression confirmed with the Structured Clinical Interview for DSM-IV disorders were treated with an SSRI, interpersonal psychotherapy, or their combination for nine months. The emergence of mania/hypomania was carefully monitored throughout the study using the Young Mania Rating Scale and clinical assessment.
Results: Overall, eight patients experienced TEMH. The incidence of this event was 3.0% in patients treated with an SSRI and 0.9% in patients treated with IPT alone. Among patients treated with an SSRI, the difference between sites was higher than expected by chance alone (6.8% at Pisa and 0% at Pittsburgh, p = 0.002). Despite the adoption of an identical protocol at the two sites, some demographic and clinical characteristics of participants may account for this unexpected result. Alternatively, the greater number of episodes and earlier age of onset at the Pittsburgh site suggests that the unipolar course of illness was more clearly established prior to study entry.
Conclusions: TEMH is an infrequent event, occurring in 2.3% of patients treated for major depression. Nevertheless, its consequences are clinically relevant and require prompt and appropriate therapeutic interventions. For this reason, recognising those patients at risk for such an event is of paramount clinical significance. The observed difference in the incidence of TEMH between the two sites requires further investigation.