Positive social connections, such as intimate relationships and marriage, play a central role in well-being and reduced risk for a wide range of disorders. This issue of Psychosomatic Medicine features three original research articles on this topic. An editorial by Dr. Timothy Smith provides an integrative perspective on the articles, illustrating the application of these investigations in “relationship science.” The editorial also discusses the biobehavioral and psychological mechanisms involved and outlines directions for future research.
Perceived partner responsiveness is examined by Stanton et al. in a study combining ambulatory assessments of perceived partner support with longitudinal survival analysis. The authors tested whether the degree to which people perceive that their romantic partners understand, care for, and appreciate them was associated with a reduced risk of all-cause mortality. They also evaluated daily negative affect (NA) reactivity and positive affect reactivity, and they found that greater daily NA reactivity was related to a higher likelihood of death 10 years later.
Intimacy can buffer psychobiological stress-reactivity, suggesting that emotional and physical closeness might trigger biological mechanisms that underlie beneficial health effects in couple relationships. Ditzen et al. studied the behavior of couples in various lab-based stress conditions. Couples’ spontaneous nonverbal expressions of intimacy before and after psychosocial stress exposure appear to regulate the effects of acute environmental demands on established biological indices of stress response.
In the context of a marriage, spouses may differ in their anger-coping response style. Discordant response styles within couples may lead to increased conflict, which, in turn, may undermine long-term health. Examining data from a three-decade follow-up, Bourassa et al. found that husbands and wives were at greater risk of early death when their anger-coping response styles differed. Degree of mismatch between spouses’ response styles may be an important long-term predictor of spouses’ early mortality risk.
Central nervous system (CNS) serotonin exerts both excitatory and inhibitory effects on the sympathetic nervous system (SNS) in animals, but less is known about its effects in healthy humans. Boyle et al. examined the effect of lowering and enhancing CNS serotonin, via tryptophan infusion and depletion, on plasma catecholamine levels. Tryptophan depletion increased both epinephrine and norepinephrine levels whereas tryptophan enhancement increased epinephrine and decreased norepinephrine. Further research will be required to determine whether the findings can be used to develop interventions to reduce health-damaging effects of stress-induced increases in catecholamines.
Patients with cancer experience multiple symptoms, which commonly appear in clusters. Oh et al. examined whether altered hypothalamus-pituitary-adrenal (HPA) axis function in patients with advanced lung cancer underlies concurrent multiple symptoms. The HPA axis dysfunction seen in reduced cortisol awakening response with flattened diurnal cortisol rhythm was associated with severity of a symptom cluster in the patients. Altered HPA axis function was closely associated with functional status and levels of perceived burden of symptoms.
The pathophysiology of irritable bowel syndrome (IBS) is not completely understood, although it is known that patients with IBS have a high prevalence of psychiatric comorbidity, mainly depression and anxiety disorders. Psychiatric conditions are associated with circadian disturbances in peripheral melatonin levels. Melatonin, produced in the gastrointestinal tract, in turn influences gut motility. In young adult psychiatric patients, Söderquist et al. found that salivary melatonin levels after lunch were associated with gastrointestinal symptoms, suggesting a link between IBS symptoms and regulation of melatonin in this group.
In patients with coronary artery disease, acute mental stress can induce transitory perfusion abnormalities that have been associated with adverse prognosis. The mechanisms underlying mental stress–induced myocardial ischemia (MSIMI) are not clear and could differ by sex. In a sample of patients with a recent myocardial infarction, Almuwaqqat et al. found that MSIMI is associated with coronary atherosclerotic burden in men but not in women. MSIMI in women may therefore be driven by alternative mechanisms such as coronary microvascular disease.
Spousal bereavement is linked to increased mortality and morbidity from conditions marked by elevated levels of inflammation, such as cardiovascular disease. Chirinos et al. examined the association between self-reported sleep disturbances and inflammation after adjusting for depressive symptoms. Results showed that the link varies by bereavement status, highlighting a potential role of sleep disturbance as a pathway leading to increased inflammation in bereavement.
Depressive symptoms are highly prevalent in patients who require ongoing dialysis. Haverkamp et al. examined long-term associations between inflammation markers and depressive symptoms. No significant associations were found between inflammation markers (HsCRP, IL-1β, IL-6, IL-10 and TNFα) at baseline and depressive symptoms at 6 and 12 months’ follow-up and vice versa. The results are more supportive of an associative rather than a causal relationship between inflammation and depressive symptoms in chronic dialysis patients.
Psychological stress is an important risk factor associated with declines in cognitive and brain health; response time-based tasks, reflecting speed of information processing, are commonly used for assessing cognitive performance. Stawski et al. tested response time in older adults alongside their self-report assessments of affect, physical symptoms, and daily stressors, and found that negative affect reactions to daily stressors are associated with response time inconsistency – trial to trial variations that may be indicative of cognitive decline.
Exposure therapy is an effective first-line treatment for spider phobia. Having observed modulation of threat processing by afferent cardiac signals, Watson et al. tested whether interoceptive information concerning cardiovascular arousal can influence the outcomes of computerized exposure therapy for spider phobia. Subjective aversion to spiders showed most improvement in self-reported spider phobia symptoms if exposure intervention occurred at cardiac systole; individuals with poorer interoception showed the greatest subjective benefit from linking spider exposure to cardiac afferent signals.
Xia et al. exposed rats to chronic unpredictable mild stress to investigate the effects of the traditional Chinese medication Zhike-Houpu herbal pair (ZKHPHP). Core behavioral and biochemical features of depression, including anhedonia, decreases in exploring behavior, and serotonin receptor dysregulation, were measured. At higher levels of 10g/kg and, particularly, 20g/kg, ZKHPHP was found to have significant anti-depressive-like effects without gastrointestinal side effects. Upregulation of the 5HT1A receptors in the hippocampal CA1 region may play a role in the beneficial effects of Zhike-Houpu herbal pair.