Anhedonia and lack of motivation are prevalent in patients with schizophrenia, depression and bipolar disorder, and the exploration of their intrinsic behavior and neural mechanisms is of great significance for the formulation of effective treatment options and the rehabilitation of social functioning.
There is growing evidence that the nature of anhedonia may not be merely a decline in the ability to experience pleasure or a defect in the motivation to pursue rewards, but more likely to be related to the failure of the transformation process of emotional experience into an effort-making behavior.
Most previous studies have been limited to behavioral measurements, typically targeting only one diagnostic group of patients, and lacking cross-diagnostic comparisons between patients with different psychiatric disorders.
Recent research by Chen Chuqiao, a researcher at the Key Laboratory of Neuropsychology and Applied Cognitive Neurosciences of the Key Laboratory of Mental Health of the Chinese Academy of Sciences, and his team have shown that although patients with schizophrenia, depression and bipolar disorder all showed lower ability to experience pleasure and lack of motivation, the patterns of emotional-behavioral separation in these patients differed.
To date, there have been no neuroimaging studies comparing the neural mechanisms of anhedonia and lack of motivation observed in patients with schizophrenia, depression, and bipolar disorder. To this end, researcher Chen Chuqiao and his team conducted a study that compared the neural mechanisms of the reward for the efforts of patients with the above three diseases across diagnosis. They recruited 20 people with schizophrenia, 23 people with depression, 17 people with bipolar disorder, and 30 healthy individuals to complete a reward for their efforts in a 3T brain scanner (EEfRT). The task adopts event-related design, and six conditions are formed by the interaction of reward range (low, high) and reward probability (20%, 50%, 80%). The selection ratio for high-effort tasks at different probabilities is used to reflect the motivation of participants to pursue rewards.
The results of the study showed that the buckle gyrus, medial frontal gyrus, and midfrontal gyrus showed common activation when the three groups of patients performed the EEfRT task. Compared with the healthy control group, the functional connection between the right caudate nucleus and the left amygdala, the left hippocampus, and the left shell nucleus of patients with schizophrenia increased with the increase in the reward range. Activation of the right superior temporal gyrus increased in patients with depression, while changes in the functional connections between the caudate nucleus and right cingulate gyrus, the left central posterior gyrus, and the left sub-parietal lobules were weaker than in the healthy control group. As the probability of reward increases, left anterior wedge activation increases in patients with bipolar disorder, while activation of the left dorsolateral prefrontal cortex decreases.
Taken together, the study reveals the commonality and relative uniqueness of the neural mechanisms associated with effort-based decision-making in patients with schizophrenia, depression, and bipolar disorder. These findings have potential implications for developing neuromodulatory interventions to alleviate anhedonia and lack of motivation in patients.
The research was supported by the National Key Research and Development Program, the National Natural Science Foundation of China, the Beijing Municipal Science and Technology Commission Fund, the Beijing Municipal Science and Technology Leading Talent Training Project, the Philip K. H. Wong Foundation, the Shandong Provincial Natural Science Foundation, the Humanities and Social Science Research Project of the Ministry of Education, and the Key Laboratory of the Mental Health Institute.
The study was published online in the European Archives of Psychiatry and Clinical Neuroscience.
Thesis Information:
Wang, Y. Y., Wang, Y., Huang, J., Sun, X. H., Wang, X. Z., Zhang, S. X., Zhu, G. H., Lui, S. S. Y., Cheung, E. F. C., Sun, H. W., Chan, R. C. K.* (2022). Shared and distinct reward neural mechanism among patients with schizophrenia, major depressive disorder and bipolar disorder: An effort-based functional imaging study. European Archives of Psychiatry and Clinical Neuroscience,https://doi.org/10.1007/s00406-021-01376-3
Wang, Y. Y., Ge, M. H., Zhu, G. H., Jiang, N. Z., Wang, G. Z., Lv, S. X., Zhang, Q., Guo, J. N., Tian, X., Lui, S. S. Y., Cheung, E. F. C., Heerey, E. A., Sun, H. W., Chan, R. C. K.* (2020) Emotion-behavior decoupling in individuals with schizophrenia, bipolar disorder, and major depressive disorder. Journal of Abnormal Psychology, 129:331-342
Xie, D. J.,#, Lui, S. S. Y.#, Geng, F. L., Yang, Z. Y., Zou, Y. M., Li, Y., Yeung, H. K. H., Cheung, E. F. C., Heerey, E. A., Chan, R. C. K.* (2018). Dissociation between affective experience and motivated behaviour in schizophrenia patients and their unaffected first-degree relatives and schizotypal individuals. Psychological Medicine, 48(9), 1474-1483.
Lui, S.S. Y., Liu, A. C. Y., Chui, W. W. H., Li, Z., Geng, F., Wang, Y., Heerey, E. A., Cheung, E. F. C., Chan, R. C.. K. * (2016). The nature of anhedonia and avolition in patients with first-episode schizophrenia. Psychological Medicine46(2), 437-447.
Source: Chen Chuqiao Research Group