Biological Psychiatry：抑郁症中快乐与痛苦相互纠缠

伍迪艾伦在影片《爱与死》（Love and Death）中写道：“爱是恒久忍耐… 幸福是相爱，幸福也是忍耐”。 这种快乐和痛苦的相互纠缠可能是抑郁症的一种症状。斯坦福大学的研究人员Brian Knutson博士等人在 4月1日的爱思唯尔期刊《生物精神病学》（Biological Psychiatry ）发表了一篇利用功能性磁共振成像技术来研究区间大脑活动的最新研究，研究发现可能有助于进一步了解抑郁症中快乐和痛苦是怎样相互联系的。

研究人员让患有抑郁症和不患抑郁症的人参与活动，在活动中他们将会赢钱或者输钱，同时通过功能性磁共振成像技术来检测活动参与者大脑的活动。论文的第一作者Brian Knutson博士这样解释他们的发现：“当期望赢钱时，无论是抑郁症患者或是非抑郁症患者的伏隔核都被激活了（伏隔核被认为与对快乐的期望有关），然而只有抑郁症患者的大脑前扣带回皮层（大脑中跟解决矛盾冲突相关的区域）的活动增强了。”

《生物精神病学》主编、耶鲁大学医学院的John H. Krystal博士评论说：“该项研究成果说明了抑郁症并不是单纯的快感缺乏，而是处理奖赏信息时的神经元活动受到了处理惩罚信息的神经元活动的干扰。”Knutson博士同意这种看法：“这同抑郁症患者在处理正面信息过程中遇到困难是一致的，同时更为明确地说明了抑郁症患者在面对可能获得奖赏的机会的时候实际上正经历着内心的矛盾冲突。”

Krystal博士认为：“该研究潜在说明了有些抑郁症可能只是通常意义上的情感上的痛苦、失望和困惑，而不是快感缺乏。”Knutson博士同其同事现正在检验这种在期望奖赏时对矛盾体验的增加是否阻碍了抑郁症患者的恢复。（来源：EurekAlert!中文版）

原始出处：

（Biological Psychiatry ），Volume 63, Issue 7, 1 April 2008, Pages 686-692，Brian Knutson，Ian H. Gotlib

Brian Knutson^{, a,} , Jamil P. Bhanji^a, Rebecca E. Cooney^a, Lauren Y. Atlas^a and Ian H. Gotlib^a
aDepartment of Psychology, Stanford University, Stanford, California.
Received 9 July 2006;  revised 26 May 2007;  accepted 16 July 2007.  Available online 4 October 2007.

Background

Reduced responsiveness to positive incentives is a central feature of Major Depressive Disorder (MDD). In the present study, we compared neural correlates of monetary incentive processing in unmedicated depressed participants and never-depressed control subjects.

Methods

Fourteen currently depressed and 12 never-depressed participants underwent functional magnetic resonance imaging while participating in a monetary incentive delay task. During the task, participants were cued to anticipate and respond to a rapidly presented target to gain or avoid losing varying amounts of money.

Results

Depressed and never-depressed participants did not differ in nucleus accumbens (NAcc) activation or in affective or behavioral responses during gain anticipation. Depressed participants did, however, exhibit increasing anterior cingulate activation during anticipation of increasing gains, whereas never-depressed participants showed increasing anterior cingulate activation during anticipation of increasing loss. Depressed participants also showed reduced discrimination of gain versus nongain outcomes.

Conclusions

The present findings indicate that although unmedicated depressed individuals have the capacity to experience positive arousal and recruit NAcc activation during gain anticipation, they also exhibit increased anterior cingulate cortex activation, suggestive of increased conflict during anticipation of gains, in addition to showing reduced discrimination of gain versus nongain outcomes.