Nicole K. Y. Tang

Suicidality in chronic pain : a review of the prevalence, risk factors and psychological links

BACKGROUND This paper reviews and integrates the growing literature concerning the prevalence of and risk factors for suicidality in chronic pain. METHOD A series of systematic searches in MEDLINE and PsychINFO identified 12 relevant articles examining suicide, suicide attempts, and suicidal ideation in chronic pain. A selection of theoretical and empirical work identifying psychological processes that have been implicated in both the pain and suicide literature and which may be related to increased suicidality was also reviewed. RESULTS Relative to controls, risk of death by suicide appeared to be at least doubled in chronic pain patients. The lifetime prevalence of suicide attempts was between 5% and 14% in individuals with chronic pain, with the prevalence of suicidal ideation being approximately 20%. Eight risk factors for suicidality in chronic pain were identified, including the type, intensity and duration of pain and sleep-onset insomnia co-occurring with pain, which appeared to be pain-specific. Helplessness and hopelessness about pain, the desire for escape from pain, pain catastrophizing and avoidance, and problem-solving deficits were highlighted as psychological processes relevant to the understanding of suicidality in chronic pain. CONCLUSIONS Programmatic research is urgently required to investigate the role of both general and pain-specific risk factors for suicidality, to examine how the psychological processes mentioned above mediate or exacerbate suicidality, and to develop enhanced interventions for pain patients at risk.

Prevalence and correlates of clinical insomnia co‐occurring with chronic back pain

Given the suggestion of a reciprocal relationship between sleep and pain and the recognition of sleep as an important parameter in determining quality of life, there is increasing research interest in sleep disturbance linked to chronic pain. The present study aimed to provide an estimate of the prevalence of ‘clinical insomnia’ in patients attending a specialist pain clinic and identify factors associated with it. Seventy chronic back pain patients and 70 gender‐ and age‐matched pain‐free controls completed a set of questionnaires measuring sleep (Insomnia Severity Index; ISI), pain (Short‐Form McGill Pain Questionnaire) and a selection of general and specific psychological variables (Hospital Anxiety and Depression Scale, Short Health Anxiety Inventory). Scores suggestive of clinical insomnia (ISI ≥ 15) were noted in 53% of chronic pain patients, when compared with only 3% in pain‐free controls. Significant positive correlations with insomnia severity were detected for all six variables of interest (pain intensity, sensory pain ratings, affective pain ratings, general anxiety, general depression and health anxiety). Affective pain ratings and health anxiety were the best predictors of insomnia severity in this sample, accounting for 30% of the total variance, even when present pain intensity was controlled for. Affective pain remained as a significant predictor of insomnia severity when both the effect of pain intensity and the effects of anxiety and depression were controlled for. Future research should consider investigating the role of pain appraisal and health anxiety in the development and manifestation of insomnia concomitant to chronic pain.

(Mis)perception of sleep in insomnia: a puzzle and a resolution.

Insomnia is prevalent, causing severe distress and impairment. This review focuses on illuminating the puzzling finding that many insomnia patients misperceive their sleep. They overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST), relative to objective measures. This tendency is ubiquitous (although not universal). Resolving this puzzle has clinical, theoretical, and public health importance. There are implications for assessment, definition, and treatment. Moreover, solving the puzzle creates an opportunity for real-world applications of theories from clinical, perceptual, and social psychology as well as neuroscience. Herein we evaluate 13 possible resolutions to the puzzle. Specifically, we consider the possible contribution, to misperception, of (1) features inherent to the context of sleep (e.g., darkness); (2) the definition of sleep onset, which may lack sensitivity for insomnia patients; (3) insomnia being an exaggerated sleep complaint; (4) psychological distress causing magnification; (5) a deficit in time estimation ability; (6) sleep being misperceived as wake; (7) worry and selective attention toward sleep-related threats; (8) a memory bias influenced by current symptoms and emotions, a confirmation bias/belief bias, or a recall bias linked to the intensity/recency of symptoms; (9) heightened physiological arousal; (10) elevated cortical arousal; (11) the presence of brief awakenings; (12) a fault in neuronal circuitry; and (13) there being 2 insomnia subtypes (one with and one without misperception). The best supported resolutions were misperception of sleep as wake, worry, and brief awakenings. A deficit in time estimation ability was not supported. We conclude by proposing several integrative solutions.

Effects of mood on pain responses and pain tolerance: An experimental study in chronic back pain patients

&NA; Although chronic pain and depression commonly co‐occur, causal relationships have yet to be established. A reciprocal relationship, with depression increasing pain and vice versa, is most frequently suggested, but experimental evidence is needed to validate such a view. The most straightforward approach would be a demonstration that increasing or decreasing depressed mood predictably modifies pain responses. The current experiment tested whether experimentally induced depressed and happy mood have differential effects on pain ratings and tolerance in 55 patients suffering from chronic back pain. Participants were randomly assigned to depressed, neutral (control) or elated mood induction conditions. They completed a physically passive baseline task prior to receiving mood induction, then a clinically relevant physically active task (holding a heavy bag) to elicit pain responses and tolerance. Measures were taken immediately after the baseline task and immediately after the mood induction to assess the changes in mood, pain ratings and tolerance before and after the experimental manipulation. Results indicate that the induction of depressed mood resulted in significantly higher pain ratings at rest and lower pain tolerance, whilst induced happy mood resulted in significantly lower pain ratings at rest and greater pain tolerance. Correlations between changes in mood on the one hand and changes in pain response and pain tolerance on the other hand were consistent with these findings. It is concluded that, in chronic back pain patients, experimentally induced negative mood increases self‐reported pain and decreases tolerance for a pain‐relevant task, with positive mood having the opposite effect.

Correcting distorted perception of sleep in insomnia: a novel behavioural experiment?

Patients with primary insomnia overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST). The present study aimed to test the utility of a novel behavioural experiment designed to correct distorted perception of sleep among patients diagnosed with primary insomnia. Individuals with primary insomnia were asked to wear an actigraph and keep a sleep diary for three nights. On the following day, half were shown the discrepancy between the data recorded on the actigraph and their sleep diary (Shown-Discrepancy Group), the other half were not shown the discrepancy (No-Demonstration Group). Participants were then asked to wear the actigraph and keep a sleep diary for three further nights. Following the behavioural experiment, the Shown-Discrepancy Group estimated their SOL more accurately and reported less anxiety and preoccupation about sleep compared to the No-Demonstration Group. The theoretical and clinical implications of these findings are discussed.

Altering misperception of sleep in insomnia: behavioral experiment versus verbal feedback.

Forty-eight individuals with insomnia were asked to wear an actigraph and keep a sleep diary for 2 nights. On the following day, half were shown the discrepancy between the data recorded on the actigraph and their sleep diary via a behavioral experiment, whereas the other half were told of the discrepancy verbally. Participants were then asked to monitor their sleep for 2 further nights to index the effect of these interventions. Although both reduced sleep misperception, the behavioral experiment (effect size: 0.79 to 1.25) led to greater reduction in self-reported sleep impairment, insomnia symptoms, and sleep-related anxiety and distress compared with verbal feedback (effect size: -0.06 to 0.31). Further, the patients regarded the behavioral experiment as a more beneficial and acceptable intervention strategy than verbal feedback.

Mental defeat in chronic pain : initial exploration of the concept

Objectives“Mental defeat” has been found to be an important psychologic reaction to painful trauma. Chronic pain patients also report mental defeat in relation to their experience of pain episodes. A measure of mental defeat was devised and evaluated in terms of (1) psychometric properties and (2) specificity of scores in relation to disabling chronic pain. MethodsA total of 304 participants completed the Pain Self Perception Scale, a questionnaire designed to measure mental defeat as a reaction to pain. Participants also completed the Short-Form McGill Pain Questionnaire and Hospital Anxiety and Depression Scale. Chronic pain patients from a tertiary hospital clinic (n=94) were compared with patients experiencing acute pain (n=38), pain-free controls (n=79), community volunteers suffering from chronic pain (n=32) or acute pain (n=30), and patients diagnosed with anxiety disorders (n=31). Test-retest reliability was assessed in subsamples of chronic pain patients and community volunteers. ResultsThe mental defeat measure was both internally consistent and reliable. Chronic pain patients showed elevated levels of mental defeat relative to all other groups, including people with chronic pain of the same intensity of pain who were not seeking treatment. Pain-specific mental defeat may be linked to disability and the seeking of specialist treatment. ConclusionsResearch on mental defeat may allow the development of new treatment strategies for chronic pain syndromes and a better understanding of the link between chronic pain, depression, and posttraumatic stress disorder.

Time estimation ability and distorted perception of sleep in insomnia.

Although it is an established finding that people with insomnia characteristically overestimate the time they have taken to get to sleep and underestimate the total amount of time they have slept, little is known about the mechanisms that underpin this phenomenon. Accordingly, this study sought to investigate whether the tendency to misperceive sleep among patients with insomnia is accounted for by (a) a general deficit in time estimation ability or (b) the context in which the time estimates are made. Twenty individuals with insomnia and 20 individuals who did not have insomnia were asked to perform two time estimation tasks; one in the laboratory during the day and one in the participants own bedroom during the night. The two groups were compared with respect to the accuracy of their performance in estimating unfilled temporal intervals of various lengths. The results indicated that the performance of the insomnia group was no different from that of the noninsomnia group, regardless of the context in which the time estimates were made. Time overestimation correlated positively with cognitive and physiological arousal experienced during the time estimation tasks. These findings argue against the hypothesis that individuals with insomnia misperceive their sleep simply because they are poor estimators of time. Future research is required to test the hypothesis that increased cognitive arousal (worry) and physiological arousal are candidate mechanisms that underpin sleep misperception.

Better quality sleep promotes daytime physical activity in patients with chronic pain? A multilevel analysis of the within-person relationship.

Background Promoting physical activity is key to the management of chronic pain, but little is understood about the factors facilitating an individual’s engagement in physical activity on a day-to-day basis. This study examined the within-person effect of sleep on next day physical activity in patients with chronic pain and insomnia. Methods 119 chronic pain patients monitored their sleep and physical activity for a week in their usual sleeping and living environment. Physical activity was measured using actigraphy to provide a mean activity score each hour. Sleep was estimated with actigraphy and an electronic diary, providing an objective and subjective index of sleep efficiency (A-SE, SE) and a sleep quality rating (SQ). The individual and relative roles of these sleep parameters, as well as morning ratings of pain and mood, in predicting subsequent physical activity were examined in multilevel models that took into account variations in relationships at the ‘Day’ and ‘Participant’ levels. Results Of the 5 plausible predictors SQ was the only significant within-person predictor of subsequent physical activity, such that nights of higher sleep quality were followed by days of more physical activity, from noon to 11pm. The temporal association was not explained by potential confounders such as morning pain, mood or effects of the circadian rhythm. Conclusions In the absence of interventions, chronic pain patients spontaneously engaged in more physical activity following a better night of sleep. Improving nighttime sleep may well be a novel avenue for promoting daytime physical activity in patients with chronic pain.

Nonpharmacological Treatments of Insomnia for Long-Term Painful Conditions: A Systematic Review and Meta-analysis of Patient-Reported Outcomes in Randomized Controlled Trials.

STUDY OBJECTIVES Insomnia is a debilitating comorbidity of chronic pain. This study evaluated the effect of nonpharmacological sleep treatments on patient-reported sleep quality, pain, and well-being in people with long-term cancer and non-cancer (e.g., back pain, arthritis, fibromyalgia) pain conditions. DESIGN We systematically searched Cochrane CENTRAL, MEDLINE, Embase, and PsychINFO for relevant studies. Search period was set to inception of these databases to March 2014. Studies were included if they were: original randomized controlled trials (RCTs); testing a nonpharmacological intervention; that targets sleep; in adults; with painful health conditions; that has a control group; includes a measure of sleep quality; and at least one other health and well-being outcome. MEASUREMENT AND FINDINGS Means and standard deviations of sleep quality, pain, fatigue, depression, anxiety, physical and psychological functioning were extracted for the sleep treatment and control groups at baseline, posttreatment and final follow-up. Methodological details concerning the treatment, participants, and study design were abstracted to guide heterogeneity and subgroup analyses. Eleven RCTs involving 1,066 participants (mean age 45-61 years) met the criteria for the meta-analysis. There was no systematic evidence of publication bias. Nonpharmacological sleep treatments in chronic pain patients were associated with a large improvement in sleep quality (standardized mean difference = 0.78, 95% Confidence Interval [0.42, 1.13]; P < 0.001), small reduction in pain (0.18 [0, 0.36] P < 0.05), and moderate improvement in fatigue (0.38 [0.08, 0.69]; P < 0.01) at posttreatment. The effects on sleep quality and fatigue were maintained at follow-up (up to 1 year) when a moderate reduction in depression (0.31, [0.09, 0.53]; P < 0.01) was also observed. Both cancer and non-cancer pain patients benefited from nonpharmacological sleep treatments. Face-to-face treatments achieved better outcomes than those delivered over the phone/internet. CONCLUSIONS Although the body of evidence was small, nonpharmacological sleep interventions may represent a fruitful avenue for optimizing treatment outcomes in patients with chronic pain. REGISTRATION PROSPERO registration: CRD42013004131.