The emerging role of euthymia in psychotherapy research and practice.

Euthymia is generally conceived in negative terms (absence of psychiatric disorders), yet it may also indicate a trans-diagnostic construct where lack of mood disturbances is associated with positive affects and psychological well-being (flexibility, consistency and resilience). Specific strategies for the assessment of euthymia are available, including both observer- and self-rated instruments that may be applied within a clinimetric framework encompassing macro-analysis and staging. Self-observation of psychological distress in a diary is the basic, neglected method of cognitive and behavioral strategies. Self-observation of instances of well-being may become the source of psychotherapeutic work geared to euthymia, combined with cognitive restructuring, homework assignments and clinical interaction. Well-Being Therapy (WBT) specifically pursues this approach. It may be incorporated in a therapeutic plan based on clinical reasoning and case formulation. The target of euthymia may also be accomplished by other psychotherapeutic strategies, such as mindfulness-based cognitive therapy and acceptance and commitment therapy. Clinical applications encompass decreasing vulnerability to relapse, increasing the level of recovery and modulating mood. The practice of self-observation of psychological well-being in a diary, as manualized in WBT, may trigger important developments in clinical assessment and in other psychotherapeutic techniques geared to a state of euthymia.