Table 1.

Current challenges in research on the pathological mechanisms of anhedonia in major depressive disorder (MDD)

Challenges	Potential solutions
Competing definitions for anhedonia in schizophrenia and MDD	New clinical terminology should be introduced in future versions of the diagnostic systems to facilitate identifying deficits in different aspects of reward processing in the anhedonia domain of MDD.
The weak temporal correlation and operability between reward processing and MDD	Improving the evaluation of reward processing in MDD and optimising study design to solve the problem are necessary.
Lack of specific assessment tools for anhedonia in MDD	The current commonly used anhedonia assessment tools have several limitations. The recently developed Dimensional Anhedonia Rating Scale can comprehensively reflect anhedonia features in patients with MDD; as an ideal tool, it needs to be optimised in the future for a wider population.