How the brain responds to rewards and losses may be a useful indicator of the risk of suicidal ideation among those suffering from depression and social anxiety, according to new research published in Biological Psychology.
(If you are experiencing suicidal thoughts, call the Suicide and Crisis Lifeline at 988 or follow this link to their online chat.)
Social anxiety disorder (SAD) and major depressive disorder (MDD) are common and debilitating mental health disorders in the United States. Both disorders are associated with suicidal ideation, which refers to thoughts or wishes about ending one’s own life. Understanding the relationship between these disorders and suicidal ideation is important for identifying individuals at risk for suicide and developing interventions to help them.
“Suicidal ideation is a major public health problem that is frequently associated with depression (e.g., feelings of sadness, loss of interest in activities). Yet, there is data that indicates suicidal ideation is also prevalent in social anxiety disorder, which is characterized by fear of potential judgment by others,” said study author Heide Klumpp, an associate professor of psychiatry at the University of Illinois Chicago.
“A separate line of research also suggests suicidal ideation may involve deficits in the capacity to respond to positive events at the neural level. For example, the reward positivity (RewP) is a neurophysiological index of reward sensitivity that is believed to reflect the processing of reward-related feedback (e.g., winning money) relative to loss-related feedback (e.g., losing money) or non-reward events.”
To conduct the study, the researchers recruited 109 participants with either SAD or MDD. The participants completed various clinical measures, including structured interviews and self-report questionnaires, to assess the severity of social anxiety, depression, and suicidal ideation. The severity of social anxiety was evaluated using the Liebowitz Social Anxiety Scale (LSAS), while the severity of depression was assessed using the Hamilton Depression Rating Scale (HAMD).
The researchers also collected electroencephalograph (EEG) data from the participants during a monetary reward task to assess RewP. EEG measures brain activity by recording electrical signals from the scalp. The researchers hypothesized that this pattern of brain activity could serve as a brain-based marker of suicidal ideation.
“RewP has been shown to relate to suicidality in youth but it is unclear if it serves as a brain-based marker of suicidality in adults,” Klumpp explained. “Therefore, the goal of the study was to fill important gaps in the literature.”
Participants were randomly assigned to receive either cognitive-behavioral therapy or supportive therapy as their treatment. Cognitive-behavioral therapy is a widely used psychotherapy for SAD, MDD, and other internalizing psychopathologies. The researchers wanted to examine the effects of these treatments on suicidal ideation, capacity for pleasure (anhedonia), and the RewP. They compared the changes in symptom severity, including suicidal ideation and capacity for pleasure, between the cognitive-behavioral therapy and supportive therapy groups.
“We also examined whether 12 weeks of cognitive behavioral therapy or supportive therapy improved suicidal ideation and altered RewP as this has been under-researched, particularly in social anxiety disorder,” Klumpp told PsyPost.
The researchers collected EEG data from the participants at baseline, mid-treatment (Week 6), and post-treatment (Week 12) to assess any changes in the RewP-related outcomes over the course of treatment.
Klumpp and her colleagues found that patients with SAD and MDD had similar levels of suicidal ideation, suggesting that suicidal thoughts cut across these diagnostic boundaries. Higher levels of suicidal ideation were associated with lower reward sensitivity, even after controlling for symptom severity and age.
“The frequency and level of suicidal ideation was similar between the MDD and SAD groups suggesting suicidal ideation may be as common in social anxiety as it is in depression,” Klumpp explained. “RewP also did not differ between the MDD and SAD groups and RewP corresponded with suicidal ideation. That is, less RewP was associated with more suicidal ideation across all participants even after controlling for depression and social anxiety symptoms. The results are consistent with previous research that suggests diminished capacity to respond to positive events may be a transdiagnostic risk factor for suicidality.”
Regarding treatment outcomes, both cognitive-behavioral therapy and supportive therapy were effective in reducing social anxiety and depression symptoms, but CBT showed a greater rate of improvement.
Suicidal ideation also decreased following both treatments, indicating that psychotherapy can be beneficial for individuals with SAD or MDD. But reward sensitivity remained stable throughout the treatment process, suggesting that it may be a vulnerability marker for suicidal thoughts even when symptoms improve.
“Psychotherapy was found to be beneficial as suicidal ideation decreased following cognitive behavioral therapy or supportive therapy in the MDD and SAD groups,” Klumpp told PsyPost. “Yet RewP did not significantly change following psychotherapy. Lack of change in RewP has been shown in previous studies involving treatment with psychotherapy or medication in adults, therefore, it may be relatively stable in adults.”
The EEG task used in the study also allowed the researchers to examine both neural responses to receiving money and neural responses losing money.
“Since RewP was obtained by comparing neural response after receiving money (‘win’) versus losing money (‘loss’), it was possible to perform subsequent analysis to evaluate how these conditions related to suicidal ideation more specifically,” Klumpp said. “When evaluating win (partialling out effect for loss), results were as expected as less RewP corresponded with more suicidal ideation.”
“However, when examining loss (partialling out effect of win), which is referred to as feedback-related negativity (FN), less FN also corresponded with more suicidal ideation, which was unexpected. Taken together, less reward sensitivity and loss sensitivity may serve as vulnerability markers for suicidal ideation.”
But the study, like all research, includes some caveats.
“It will be important to replicate results in a separate study before drawing firm conclusions,” Klumpp explained. “Also, the study excluded individuals with active suicidality (e.g., having a plan or intent) or who engaged in self-harm behavior or were taking medication (e.g., antidepressants). Furthermore, major depression and social anxiety frequently co-occur, however, such comorbidity was not permitted in the study. Therefore, findings may not generalize to individuals who differ from the criteria used in the study.”
The researchers highlighted the importance of further studies to investigate the relationship between reward sensitivity and suicidal ideation and to explore other potential pathways leading to suicidal thoughts.
“Among questions that still need to be addressed is whether the RewP-suicidal ideation finding is actually transdiagnostic,” Klumpp noted. “For example, whether the relationship is observed in other disorders (e.g., generalized anxiety disorder, posttraumatic stress disorder) or in individuals at-risk for suicidality who do not have a diagnosable mental disorder. Additionally, it will be important to examine whether RewP changes following interventions that more directly aim to improve one’s capacity to respond to positive events.”
The study, “Neural responsiveness to reward and suicidal ideation in social anxiety and major depression before and after psychotherapy“, was authored by Heide Klumpp, Brian W. Bauer, James Glazer, Grace Macdonald-Gagnon, Cope Feurer, Jennifer Duffecy, Gustavo R. Medrano, Michelle G. Craske, K. Luan Phan, and Stewart A. Shankman.
