Social Rhythm Metric Research Articles

Social rhythm regularity and the onset of affective episodes in bipolar spectrum individuals

Research suggests that bipolar disorder individuals may have less social rhythm regularity than normal controls and that this may contribute to their affective symptoms and episodes. This study examined whether regularity prospectively predicted time to onset of major depressive, hypomanic and manic episodes in a sample with bipolar spectrum disorders. We recruited 414 undergraduate students from Temple University and University of Wisconsin diagnosed with cyclothymia, bipolar II disorder, or with no affective disorder (normal controls). Participants completed the Social Rhythm Metric at Time 1 and structured interviews approximately every four months for an average follow-up period of 33 months. Participants diagnosed with cyclothymia and bipolar II disorder reported significantly fewer regular activities than normal controls, and approximately half of these participants experienced a worsening course of their illness over the study duration. Survival analyses indicated that both diagnosis and social rhythm regularity significantly predicted the time to participants' first prospective onset of major depressive, hypomanic and manic episodes. Consistent with the social zeitgeber theory, bipolar spectrum participants reported less social rhythm regularity than normal controls, which prospectively predicted the survival time to affective episodes.

Regularity of Daily Activities in Stroke

Various studies have been performed using the Social Rhythm Metric (SRM), though none has been developed with stroke patients. Stroke is a pathology that provokes a strong physical and social impact caused by an abnormality in cerebral circulation. Consequently, we performed two studies to validate the SRM and translate it into Portuguese, and to evaluate the regularity of the daily activities of stroke patients. Both healthy individuals and patients with unilateral cerebral lesions were evaluated. Subjects were of both sexes and between 45 and 65 yrs of age. Participants underwent clinical evaluation and recorded the time of 17 daily activities on the SRM for two weeks. Data were analyzed by the Pearson correlation and Fisher tests. After conceptual translation into Portuguese, corrections were made to arrive at the final version. Normative SRM scores varied from 3.2 to 7.0, suggesting that the activities presented in SRM adequately represented the daily routines of the patients. A correlation was found in SRM between the weeks (r=0.84; p=0.0001), indicating instrument reliability. The mean (±SD) score of the stoke patients was 4.8 (±1.0), and the correlation between the SRM and level of neurological damage showed that patients with lower SRM values were more physically compromised (r=−0.29; p=0.04), suggesting that SRM may be a clinical predictor. Activities related to eating and the sleep‐wake cycle were rated by most patients. In all, 71% of the patients did not work, while 84% of healthy individuals did (p=0.001). Only 64% of patients left home compared to 90% of the healthy subjects (p=0.001), and 59% of patients recorded the activity of going home compared to 82% of healthy individuals (p=0.001). According to the results, there is evidence of the validity and reliability of the SRM, enabling it to be reliably used in chronobiological studies of stroke patients. Given that a less regular lifestyle may be associated with neurological compromise and a decrease in social activities, we suggest new studies with the repeated application of this instrument over the clinical evolution of the disease to better define improvement or worsening of the patient's condition in terms of their social and health aspects.

Sleep and Circadian Rhythms in Spousally Bereaved Seniors

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (≥60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), ∼36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two‐week diaries were completed, allowing the assessment of lifestyle regularity using the 17‐item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness‐eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between ∼23:00 and ∼06:40 h, achieving ∼6 h of sleep with a sleep efficiency of ∼80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at ∼01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid‐evening, with an amplitude of ∼0.8°C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time‐of‐day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long‐term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement‐related disruptions in the circadian system.

Family synchronizers: Predictors of sleep?wake rhythm for Japanese first-time mothers

The purpose of this study was to describe the association between the regularity of sleep patterns for first-time Japanese mothers in the early postpartum period and the sleep and wake activity of their infants and partners. Longitudinal time-series studies of 101 healthy Japanese childbearing couples were conducted between May 2002 and January 2003. Data were obtained from couples at 32–6 weeks pregnancy and 4–5 weeks after birth. The questionnaire packet for each father and mother included a demographic questionnaire, a sleep-wake log for 7 days, a social rhythm metric for 7 days and a morningness-eveningness questionnaire. A four-stage hierarchical multiple regression analysis was performed in which the mother’s sleep-wake rhythm strength was the dependent variable. The variance in postpartum sleep-wake rhythm strength for first-time mothers was explained by three predictor variables. Household income, the mother’s chronotype during pregnancy and the father’s daily social rhythm at 4–5 weeks after birth made unique contributions to the variance (24.7%) in the mother’s sleep-wake rhythm strength at 4–5 weeks postpartum. A mother’s own tendency to be a morning or evening chronotype and the regularity of the father’s daily schedule of activities appear to influence first-time mother’s sleep-wake rhythm strength during early postpartum recovery more than disruptions from the infant’s sleep-wake activity itself. Health-care providers should counsel couples on how factors associated with the parents themselves may impact on the regularity of a mother’s sleep patterns.

The Importance of Routine for Preventing Recurrence in Bipolar Disorder

The Importance of Routine for Preventing Recurrence in Bipolar Disorder

Daily activities and sleep quality in college students

There is growing evidence that social rhythms (e.g., daily activities such as getting into or out of bed, eating, and adhering to a work schedule) have important implications for sleep. The present study used a prospective measure of daily activities to assess the relation between sleep and social rhythms. College students (n=243) 18 to 39 yrs of age, completed the Social Rhythm Metric (SRM) each day for 14 d and then completed the Pittsburgh Sleep Quality Index (PSQI). The sample was divided into groups of good or poor sleepers, according to a PSQI cut‐off score of 5 points and was compared on the regularity, frequency, timing, and extent of social engagement during activities. There was a lower frequency and less regularity of social rhythms in poor sleepers relative to good sleepers. Good sleepers engaged more regularly in activities with active social engagement. Earlier rise time, first consumption of a beverage, going outdoors for the first time, and bedtime were associated with better sleep. Greater variability in rise time, consuming a morning beverage, returning home for the last time, and bedtime were associated with more disturbed sleep. The results are consistent with previous findings of reduced regularity in bedtime and rise time schedules in undergraduates, other age groups, and in clinical populations. Results augment the current thought that regulating behavioral zeitgebers may be important in influencing bed and rise times, and suggest that engaging in activities with other people may increase regularity.

Lifestyle Regularity Measured by The Social Rhythm Metric in Parkinson's Disease

Parkinson's disease (PD) is a chronic progressive motor disorder that may present with a spectrum of symptoms and disease severity. Therapy is frequently associated with motor fluctuations and dyskinesias; therefore, monitoring of motor fluctuations and daily abilities is important for adequate management. The Social Rhythm Metric (SRM) is a diary‐like questionnaire that quantifies the extent to which a person's life is regular vs. irregular on a daily basis with respect to event timing. Lifestyle regularity has been assessed by the SRM in other clinical situations. The aim of this study was to evaluate lifestyle regularity in a population with PD using the SRM and its relationship to clinical and therapeutic factors. Twenty‐eight consecutive patients with PD and 14 control subjects were studied. Severity of motor dysfunction was evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS). Depressive symptoms were assessed with the Montgomery Asberg Depressive Rating Scale (MADRS), sleep quality with the Pittsburgh Sleep Quality Index (PSQI), and subjective daytime sleepiness with the Epworth sleepiness scale. Daily lifestyle regularity was assessed by the SRM for 2 weeks. Patients with PD had lower SRM scores than controls, and those with motor fluctuations had even lower scores (p=0.04). Patients with motor fluctuations showed more clinical disability (p=0.01), a worse quality of sleep (p=0.02), and more depressive symptoms (p=0.02). SRM results were correlated with PSQI values (p=0.016). Our findings show that the regularity of daily activities as measured by the SRM is disorganized in patients with PD and that this irregularity is related to sleep quality.

Illuminating the Impact of Habitual Behaviors in Depression

Researchers have hypothesized that habitual behaviors are zeitgebers for the circadian clock. However, few studies have examined the relationship between habitual behaviors and light, the strongest zeitgeber. Depression is an ideal model in which to explore this relationship because depression is a disorder associated with disruptions in circadian biological activity, sleep, and social rhythms (or patterns of habitual behaviors). We hypothesized that individuals with fewer habitual behaviors have less average exposure to light from morning rise time to evening bedtime and that a reduction in light exposure increases the likelihood of depression. Thirty‐nine depressed and 39 never‐depressed participants wore an ambulatory light monitor and completed the Social Rhythm Metric over the course of 2 weeks. Linear and logistic regression techniques were used to calculate regression coefficients, and confidence limits based on the distribution of the product of two normal random variables were computed to test the significance of the mediation effect. Infrequent habitual behaviors were associated with a decrease in average levels of light exposure, and low levels of light increased the likelihood of depression. This mediation effect was partial; the overall number of habitual behaviors had a direct relationship with depression above and beyond the association with light exposure. Longitudinal studies are needed to empirically demonstrate the direction of relationships between each of the variables tested.

The Relationship Between Lifestyle Regularity and Subjective Sleep Quality

In previous work we have developed a diary instrument—the Social Rhythm Metric (SRM), which allows the assessment of lifestyle regularity—and a questionnaire instrument—the Pittsburgh Sleep Quality Index (PSQI), which allows the assessment of subjective sleep quality. The aim of the present study was to explore the relationship between lifestyle regularity and subjective sleep quality. Lifestyle regularity was assessed by both standard (SRM-17) and shortened (SRM-5) metrics; subjective sleep quality was assessed by the PSQI. We hypothesized that high lifestyle regularity would be conducive to better sleep. Both instruments were given to a sample of 100 healthy subjects who were studied as part of a variety of different experiments spanning a 9-yr time frame. Ages ranged from 19 to 49 yr (mean age: 31.2 yr, s.d.: 7.8 yr); there were 48 women and 52 men. SRM scores were derived from a two-week diary. The hypothesis was confirmed. There was a significant (rho=−0.4, p<0.001) correlation between SRM (both metrics) and PSQI, indicating that subjects with higher levels of lifestyle regularity reported fewer sleep problems. This relationship was also supported by a categorical analysis, where the proportion of “poor sleepers” was doubled in the “irregular types” group as compared with the “non-irregular types” group. Thus, there appears to be an association between lifestyle regularity and good sleep, though the direction of causality remains to be tested.

Comparison of Long-Term Monitoring Methods for Bipolar Affective Disorder

Long-term monitoring is a clinical necessity in bipolar affective disorder. The most important requirements are usability and value for clinical decisions. Four methods of long-term monitoring – (1) the Adjective Mood Scale by von Zerssen, (2) Kraepelin’s early life charts, (3) the NIMH Life Chart Method by Leverich and Post and (4) the Social Rhythm Metric by Monk – were compared regarding the acceptance by patients, the time commitment needed for documentation and training as well as the usability for the clinician regarding psychotherapy and decision support in pharmacotherapy. The Adjective Mood Scale is easiest to learn, Kraepelin’s life chart offers the best graphical presentation, the NIMH life charts offer the best clinical decision support and the Social Rhythm Metric integrates a psychotherapeutic approach.

Relationship between social rhythms and mood in patients with rapid cycling bipolar disorder

Disruptions in the sleep–wake cycle frequently characterize affective illness and have led to a number of theories linking sleep–wake and/or circadian rhythm disturbance to affective illness. Recently, researchers have expanded these chronobiological theories to include the role of lifestyle regularity, or daily social rhythms. In this study, the Social Rhythm Metric (SRM) was used to explore the relationship between social rhythms and mood in patients with rapid cycling bipolar disorder and to compare the social rhythms of patients with those of healthy control subjects. Patients' SRM scores and activity level indices were significantly lower than those of control subjects. In addition, the timing of five, mostly morning, activities was phase delayed in patients compared to control subjects. Patients also demonstrated a phase delay in the timing of morning activities during depression compared to hypomania or euthymia. The phase changes in the timing of morning activities are consistent with other data implicating morning zeitgebers in the pathophysiology of rapid cycling bipolar disorder.

Generalized Covariance-Adjusted Discriminants: Perspective and Application

When discriminant analysis is used in practice for assessing the usefulness of diagnostic markers, the lack of control over covariates motivates the need for their adjustment in the analysis. This necessity for adjustment arises especially when the researcher's aim is classification based on a set of diagnostic markers and is not based on a set of covariates for which there exists known heterogeneity among the subjects with respect to the groups under consideration. The traditional covariance-adjusted approach is restrictive for such applications in that they assume linear covariates and a normal distribution for the the feature vector. Further, there is no available method for variable selection in using such covariance-adjusted models. In this paper, we generalize the traditional covariance-adjusted model to a general normal and logistic model, where these generalized models not only relax the distributional assumptions on the feature vector but also allow for nonlinear covariates. Exact and asymptotic tests are also derived for the problem of variable selection for these new models. The methodology is illustrated with both simulated data and an actual data set from a psychiatric study on using the Social Rhythm Metric for patients with anxiety disorders.

Inducing lifestyle regularity in recovering bipolar disorder patients: Results from the maintenance therapies in bipolar disorder protocol

On the basis of theories we articulated in earlier papers (Ehlers et al 1988: Arch Gen Psychiatry 45:948-952, 1993: Depression 1:285-293), we have developed an adjunctive psychosocial intervention for patients with bipolar 1 disorder. Central to this intervention is the establishment of regularity in daily routines. In this report, we present data from a controlled investigation comparing this new treatment, interpersonal and social rhythm therapy (IPSRT), with a conventional medication clinic approach. Despite comparable changes in symptomatology over a treatment period lasting up to 52 weeks, subjects assigned to IPSRT (n = 18) show significantly greater stability (p = .047) of daily routines with increasing time in treatment, while subjects assigned to the medication clinic condition (n = 20) show essentially no change in their social routines as measured by Social Rhythm Metric (SRM-Monk et al 1990: J Nerv Ment Dis 178(2):120-126) score. We conclude that IPSRT is capable of influencing lifestyle regularity in patients with bipolar 1 disorder, with the possible benefit of protection against future affective episodes.

Differences Over the Life Span in Daily Life-Style Regularity

A diary-based instrument–the Social Rhythm Metric (SRM)–was used to assess the level of stability of daily social and behavioral rhythms in a group of 239 healthy subjects (112 male, 127 female) ranging in age from 20 to 89 years. Each subject completed the instrument for two consecutive weeks, which were averaged to yield one measure (SRM score) of life-style regularity [range 0 (least regular) to 7 (most regular)] and another of activity level index (ALI), corresponding to the number of (diary listed) activities done per week (max. = 119). SRM score increased reliably with age group at an average rate of 0.018 units per year. ALI showed an “inverted U”-shaped function with a maximum at about 50 years. SRM changes appeared not to be related to demographic differences between the age groups, although ALI differences may have been so related. No main effects or interactions were found with gender. Life-style regularity appears to increase over the life span in response to both biological and psychosocial changes and may represent an adaptation to age-related changes in the circadian system's sensitivity to entraining agents. Regular behavioral rhythms may be conducive to continued good health and well-being. (Chronobiology International, 14(3), 295–306, 1997)

Social rhythm stability following late-life spousal bereavement: associations with depression and sleep impairment

The aim of this study was to investigate changes in social rhythm stability and sleep in spousally bereaved subjects ( n = 94) and in nonbereaved elderly control subjects ( n = 45). Social rhythm stability and activity level were measured with a diary-like instrument, the Social Rhythm Metric (SRM). We observed that spousal bereavement, per se, was not associated with a lower social rhythm stability or activity level except in the presence of a major depressive episode. We also observed an inverse correlation between severity of depression and social rhythm stability, and a positive correlation between depression and both subjective and objective measures of sleep impairment. Higher social rhythm stability was correlated with better sleep in subjects with high activity levels, but not in subjects with low activity levels. Longitudinal data, including pre-bereavement assessment of social rhythm stability, are necessary to ascertain directional effects, i.e., whether loss of spouse occasions disruption of social rhythms or whether such disruption precedes sleep impairment and depression.

Regularity of daily life in relation to personality, age, gender, sleep quality and circadian rhythms.

A diary-like instrument to measure lifestyle regularity (the 'Social Rhythm Metric'-SRM) was given to 96 subjects (48 women, 48 men), 39 of whom repeated the study after at least one year, with additional objective measures of rest/activity. Lifestyle regularity as measured by the SRM related to age, morningness, subjective sleep quality and time-of-day variations in alertness, but not to gender, extroversion or neuroticism. Statistically significant test-retest correlations of about 0.4 emerged for SRM scores over the 12-30 month delay. Diary-based estimates of bedtime and waketime appeared fairly reliable. In a further study of healthy young men, 4 high SRM scorers ('regular') had a deeper nocturnal body temperature trough than 5 low SRM scorers ('irregular'), suggesting a better functioning circadian system in the 'regular' group.

Social rhythm in anxiety disorder patients.

The social rhythm metric (SRM) is a self report diary instrument which generates a numerical measure of rhythmicity of daily life behaviors. Depression researchers have proposed that life events cause disruption of social rhythmicity and this leads to disturbance in the sense of well-being and to disruption of physiologic rhythmicity known to be related to depressive episodes. We hypothesized that low rhythmicity of daily activities might also be characteristic of anxiety disorder patients. Forty-eight patients who met DSM III-R criteria for an anxiety disorder were recruited and compared with 41 previously monitored normal controls. All patients and controls completed at least two weeks of daily monitoring with the SRM. Anxiety patients underwent structured diagnostic assessment and completed demographic and clinical rating scales. SRM was analyzed according to a previously developed algorithm. Anxiety disorder patients report significantly lower regularity of daily activities than normal controls. The low SRM scores were not accounted for by the presence of comorbid affective disorder. We identify a new type of abnormality in anxiety disorder patients which has potential clinical as well as theoretical interest.

Daily Social Rhythms in the Elderly and Their Relation to Objectively Recorded Sleep

This study tested the hypothesis that the impaired sleep of healthy 71-91 year olds might be due to circadian dysfunction stemming from irregularity of life-style. Twenty-five old women, 20 old men and 21 young controls (19-28 years old) were studied in relation to 1) objective sleep as measured in the laboratory, 2) subjective sleep quality as measured by the Pittsburgh sleep quality index (PSQI) and 3) the social rhythm metric (SRM), an instrument to quantify the daily rhythms of life. Contrary to prediction, the SRM scales revealed that the older group had just as many activities completed and just as much other-person involvement as the young. Moreover, they showed a significantly greater regularity in daily life-style than the young, despite showing reliably impaired subjective and objective sleep. This suggests either that these seniors have always been regular in their life-style and that this has been protective of their health and vigor, or that their regularity has been developed as an adaptive response to age-related changes in the circadian system.

Disruption of social circadian rhythms in major depression: A preliminary report

While dysregulations of physiological circadian rhythms are common findings in depression and have been posited to be involved in the mediation of depressive episodes, only recently has the role of social circadian rhythms in the pathogenesis of depression been a focus of interest. The Social Rhythm Metric (SRM), designed to describe the regularity of a human subject's social circadian rhythms, was used in this study to compare the social rhythms of depressed patients with those of normal controls and to determine the relationship between SRM scores and depression severity. Depressed patients' SRM scores were significantly lower than those of normal controls. The SRM negatively correlated with scores on the Hamilton Rating Scale for Depression. Overall social activity was negatively correlated with a Hamilton item, social activity impairment. The results of this preliminary study support the hypothesis that social zeitgebers are disrupted in major depression.

The social rhythm metric (SRM): Measuring daily social rhythms over 12 weeks

A “Social Rhythm Metric” (SRM) of daily rhythmic behavior (developed previously) was given to 20 treated depressives (in remission) and 15 day-working control subjects for a continuous 12-week period. Long-term use of the SRM appeared feasible with no evidence of a deterioration in scores over the 12 weeks. Comparisons were made between intersubject and intrasubject variability, as well as a study of overall trends in SRM during the 12 weeks. Two further measures from the instrument—the Activity Level Index (ALI) and Other Person Involvement—were developed and shown to be useful adjuncts to the SRM. Although no simple differences in absolute SRM score emerged between patients and controls, there were significant differences in intersubject vs. intrasubject variability between the two groups. The patients showed more intrasubject variability and required more weeks of sampling to achieve a stable “trait” measure. Patients' social rhythms also appeared to be more “other person” prompted than those of controls.