Apathy : Conceptual Change and Future Direction

Song, Hoo Rim; Bahk, Won Myong

Abstract

Apathy is a common problem observed in many neuropsychiatric disorders. In the past, apathy was a conventional term that designated an absence of feeling and a flattening of affective responses. But recent research has produced the concept that the core feature of apathy is a lack of motivation and manifests as diminished goal-directed behavior, cognition, and emotion, including initiation and responsiveness deficiency. Now, apathy tends to be considered as a distinct clinical symptom and syndrome, but it is still conceptually ill-defined and there is no definite consensus on diagnostic criteria. Several rating scales such as the Apathy Evaluation Scale (AES) and Apathy Scale (AS) have been developed that assist in making a diagnosis of apathy and a measurment of severity. Neuroimaging studies have indicated that apathy is primarily a dysfunction of the frontal-subcortical system, which is called the motivational circuit, and can be divided into auto-activation, cognitive, emotional subtypes by various frontal-subcortical circuits which have been damaged. Dopamine (DA) and acetylcholine (Ach) have important roles in this area. Many studies have focused on the relationship between apathy and depression. The core feature of apathy is distinguished from depression, but they share too many incidental aspects to be divided off completely. It is because the diagnostic criteria of depression had developed before the new concept of apathy was proposed, so symptoms of apathy were included in the diagnostic criteria of depression. There is a need for consensus of definition and diagnostic criteria of apathy to facilitate future research, which may be able to get at the root of other neuropsychiatric disorders such as depression.