Identifying an abnormal electroencephalographic sleep profile to characterize major depressive disorder

REM parameters in drug-free major depressive disorder: A systematic review and meta-analysis

Previous studies revealed that rapid eye movement (REM) parameters, such as REM latency (RL) and REM density (RD) could be used as electrophysiological markers of depression. Yet these finding should be re-tested in a comorbid-free and drug-free sample. The present systematic review and meta-analysis was conducted to investigate whether drug-free and comorbid-free patients with unipolar depression differentiate from controls with respect to the RL and RD. The PubMed and Web of Science databases were screened from inception to 23 January 2023 for case-control studies comparing RL and RD of patients with unipolar depression and controls. The primary outcome was the standard mean difference. The data were fitted with a random-effects model. Meta-regressions were conducted to investigate patient characteristics and effect size. Publication bias assessment was checked by Egger's Regression and funnel plot asymmetry. Among 43 articles accepted as eligible, 46 RL and 22 RD measurements were included in the meta-analysis. The results indicated shortened RL and increased RD in the patient group than controls. Neither Egger's regression nor funnel plot asymmetry were significant for publication bias. In conclusion, our results tested within drug-free and comorbid-free samples are in line with the literature.

Central Symptoms of Insomnia in Relation to Depression and COVID-19 Anxiety in General Population: A Network Analysis

BACKGROUND

Insomnia is prevalent among the general population, and studies have shown an increase in insomnia symptoms during the novel coronavirus (COVID-19) pandemic. Despite numerous studies of insomnia, few studies have investigated insomnia symptoms in detail. In this study, we used network analysis to investigate interactions between insomnia symptoms in the general population. Furthermore, given the effect of COVID-19 on mental health, we also investigated how anxiety response to COVID-19 and depression related to insomnia symptoms.

METHODS

Data from 785 non-infected participants were used. The Insomnia Severity Index (ISI), Stress and Anxiety to Viral Epidemics-6 Scale (SAVE-6), and Patient Health Questionnaire-9 (PHQ-9) were used to measure insomnia symptoms, anxiety response to COVID-19, and depression, respectively. Network analysis was performed using R Studio. Centrality indices and edge weights were obtained, and each index was evaluated using bootstrapping methods.

RESULTS

The network revealed ISI7 (worry about current sleep pattern) to be the most central insomnia symptom. ISI7 was strongly connected to SAVE-6 total score, and ISI2 (difficulty staying asleep) was strongly connected to PHQ-9 total score.

CONCLUSION

High centrality of ISI7 supports the role of dysfunctional cognitions in etiological models of insomnia and thus the cognitive behavioral therapy for insomnia. The relationship between ISI7 and SAVE-6 is explained by transposition of worry and fear of contracting COVID-19 to worry about sleep patterns. The link between ISI2 and PHQ-9 necessitate further investigations of whether specific symptoms of insomnia are more associated with depression.

Impact of Insomnia Symptoms on the Clinical Presentation of Depressive Symptoms: A Cross-Sectional Population Study

Objective: Insomnia and depression are prevalent disorders that often co-occur. This study aimed to investigate the impact of clinically significant insomnia symptoms on the prevalence and clinical presentation of clinically significant depressive symptoms and vice versa. Methods: This study used data from the Korean Headache-Sleep Study (KHSS), a nationwide cross-sectional population-based survey regarding headache and sleep. Clinically significant insomnia symptoms were defined as Insomnia Severity Index (ISI) scores ≥ 10 and clinically significant depressive symptoms were defined as Patient Health Questionnaire-9 (PHQ-9) scores ≥ 10, respectively. We referred clinically significant insomnia symptoms and clinically significant depressive symptoms as insomnia symptoms and depressive symptoms, respectively. Results: Of 2,695 participants, 290 (10.8%) and 116 (4.3%) were classified as having insomnia and depressive symptoms, respectively. The prevalence of depressive symptoms was higher among participants with insomnia symptoms than in those without insomnia symptoms (25.9 vs. 1.7%, respectively, P < 0.001). Among participants with depressive symptoms, the PHQ-9 scores were not significantly different between participants with and without insomnia symptoms (P = 0.124). The prevalence of insomnia symptoms was significantly higher among participants with depressive symptoms than in those without depressive symptoms (64.7 vs. 8.3%, respectively, P < 0.001). The ISI scores were significantly higher among participants with insomnia and depressive symptoms than in participants with insomnia symptoms alone (P < 0.001). Conclusions: Participants with depressive symptoms had a higher risk of insomnia symptoms than did those without depressive symptoms. The severity of depressive symptoms did not significantly differ based on insomnia symptoms among participants with depressive symptoms; however, the severity of insomnia symptoms was significantly higher in participants with depressive symptoms than in those without depressive symptoms.

Anxiety predicts dyadic sleep characteristics in couples experiencing insomnia but not in couples without sleep disorders

BACKGROUND

Anxiety and depression are commonly comorbid with sleep problems. Despite growing acknowledgement that bedpartners are important determinants of sleep quality, few studies have explored mental health as a risk factor for disrupted sleep of the bedpartner. We examined whether anxiety or depression symptoms predicted an individual's sleep or their bedpartner's sleep, in couples where one partner experienced insomnia and in couples without sleep disorders.

METHODS

Fifty-two bed-sharing couples where one individual had insomnia ("Patient"), and 55 non-sleep-disordered couples completed the Beck Anxiety Inventory, Patient Health Questionnaire-9, and Insomnia Severity Index (ISI). Sleep was monitored for seven nights. Actor-Partner Interdependence Models assessed whether anxiety or depression symptoms predicted individual or dyadic sleep (wake transmission).

RESULTS

Greater anxiety symptoms predicted increased vulnerability to being woken by their bedpartner, as well as increased frequency of waking their bedpartner up during the night in Patients with insomnia, but not in non-sleep-disordered couples. Neither anxiety nor depression symptoms predicted an individual's or their bedpartner's sleep efficiency in either subsample. However, ISI was positively predicted by own anxiety and depression symptoms for Patients with insomnia and in non-sleep-disordered couples.

LIMITATIONS

The non-sleep-disordered subsample experienced only mild symptoms of anxiety and depression, potentially reducing predictive power.

CONCLUSIONS

Anxiety may help reveal social determinants of sleep in couples experiencing insomnia. These data underscore the importance of considering sleep, the bedpartner, and affective symptoms in mental health and sleep assessments.

Does objectively-assessed sleep moderate the association between history of major depressive disorder and task-switching?

BACKGROUND

Executive function and psychomotor speed are consistently impaired in patients with major depressive disorder (MDD). Persistent cognitive impairments after depression remission are thought to reflect "scarring" from the neurotoxic effects of hypothalamic-pituitary-adrenal axis activity during a depressive episode. As sleep also deteriorates with depression and restores daytime executive functions, we examined whether adequate sleep could be protective against task-switching and psychomotor impairments associated with a history of MDD.

METHODS

This cross-sectional study tested task-switching associations with MDD history, sleep, and their interaction to determine whether sleep continuity and sleep duration moderate the relationship between MDD history and task-switching performance.

RESULTS

After adjusting for age, sex, education, current depressive symptoms, and use of anti-depressants, a history of MDD, particularly recurrent MDD, was associated with slower response speed and disproportionately lower accuracy on repetition trials compared to switch trials, reflecting impaired adoption of a task-set. Regardless of MDD history, higher wake after sleep onset and shorter total sleep time were associated with slower response times, but neither sleep measure moderated the association between depression history and task-switching performance.

LIMITATIONS

This cross-sectional study cannot assess the causal direction of associations. One night of sleep in the laboratory was used to assess sleep and a single task-switching paradigm was used to assess executive function.

CONCLUSIONS

These results suggest that longer, more continuous sleep is associated with greater psychomotor speed across healthy controls and those with a history of MDD, but MDD-task-switching associations are not mitigated by longer or more continuous sleep.

Cardiopulmonary coupling analysis predicts early treatment response in depressed patients: A pilot study

This pilot study evaluated the effect of anti-depression treatment on sleep quality and symptoms of depression in patients with major depressive disorder, and identified cardiopulmonary coupling (CPC) indices for predicting early response. Forty-one Han Chinese patients with major depressive disorder were assessed for objective sleep quality before treatment (baseline) and at 2 weeks using CPC. Subjective sleep quality and depression levels were measured at baseline and 2 and 4 weeks after treatment, using the 24-item Hamilton Rating Scale for Depression (HAMD-24), Epworth Sleepiness Scale (ESS), and Pittsburgh Sleep Quality Index (PSQI). Objective and subjective sleep quality, and depression symptoms, improved after treatment. Significant correlations were found between CPC variables at baseline and depression symptom improvement after 2 weeks of treatment. Total sleep time at baseline significantly correlated with somnipathy score reduction at week 2. Total in-bed time at week 2 significantly correlated with reductions in anxiety/somatic symptoms and retardation score, and total HAMD-24 score at week 4. In binary logistic regression, the total in-bed time at baseline was significantly associated with treatment response. Our findings suggest that objective sleep quality measured by CPC analysis is useful for predicting treatment response to antidepressant treatment in patients with major depressive disorder.

The Relationship Between Childhood Trauma and Poor Sleep Health in Adulthood

OBJECTIVE

Childhood trauma has been related to adverse behavioral, mental, and health outcomes later in life. Sleep may be a potential mechanism through which childhood trauma is related to adverse health. The current retrospective study aimed to characterize the relationship between childhood trauma exposure and sleep health, a novel multidimensional measure of sleep.

METHODS

Participants (N = 161; mean [standard deviation] age = 59.85 [9.06] years; 67.7% female) retrospectively reported trauma exposure using the Trauma History Questionnaire. Childhood trauma was defined as the number of reported traumatic events before 18 years of age. Trauma exposure after 18 years of age and across the life-span was also recorded. Sleep health was derived both from diary- and actigraphy-assessed measures of sleep regularity, timing, efficiency, and duration, subjective sleep satisfaction, and daytime sleepiness from the Epworth Sleepiness Scale. The relationships between childhood trauma exposure and sleep health were examined using hierarchical linear regression, controlling for relevant covariates.

RESULTS

In unadjusted models, a greater number of childhood trauma exposures were associated with poorer diary- and actigraphy-measured sleep health in adulthood. After adjustment for current stress, depression history, and other sociodemographic covariates, greater childhood trauma remained significantly associated with poorer sleep health (diary: β = -0.20, ΔR = 0.032; actigraphy: β = -0.19, ΔR = 0.027). Trauma exposure after 18 years of age and across the life-span did not relate to diary- or actigraphy-based sleep health.

CONCLUSIONS

Childhood trauma may affect sleep health in adulthood. These findings align with the growing body of evidence linking childhood trauma to adverse health outcomes later in life.

Atrial Fibrillation and Objective Sleep Quality by Slow Wave Sleep

BACKGROUND

Self-reported poor sleep quality has been suggested in patients with AF. Slow wave sleep (SWS) is considered the most restorative sleep stage and represents an important objective measure of sleep quality. The aim of this study was to compare quantity of SWS between patients with and without AF.

METHODS AND RESULTS

We included patients with and without a documented history of AF by reviewing clinically indicated polysomnography data from a single sleep center. Patients on medications with potential influence on sleep architecture were excluded. Logistic regression was performed to determine the association between AF and SWS time (low vs. high) adjusting for age, gender, body mass index, and sleep apnea. In a 2:1 case-control set-up, a total of 205 subjects (139 with AF, 66 without AF) were included. Mean age was 62 (SD: 14.3) years and 59% were men. Patients with AF had lower SWS time (11.1 vs. 16.6 min, p=0.02). In multivariable analysis, prevalent AF was associated with low SWS independent of sleep apnea and other potential confounders (OR 2.5 [1.3, 5.0], p=0.006). Limiting the analysis to patients whose total sleep time was greater than 4 hours (by excluding N=31) resulted in more robust results (OR 3.9 [1.7, 9.7]. p=0.002).

CONCLUSION

AF is associated with more impaired sleep quality as indicated by lower quantity of SWS. More studies are needed to explore the mechanistic interactions between AF and sleep.

Characterization of oscillatory changes in hippocampus and amygdala after deep brain stimulation of the infralimbic prefrontal cortex

Deep brain stimulation (DBS) is a new investigational therapy that has generated positive results in refractory depression. Although the neurochemical and behavioral effects of DBS have been examined, less attention has been paid to the influence of DBS on the network dynamics between different brain areas, which could contribute to its therapeutic effects. Herein, we set out to identify the effects of 1 h DBS in the infralimbic cortex (IL) on the oscillatory network dynamics between hippocampus and basolateral amygdala (BLA), two regions implicated in depression and its treatment. Urethane-anesthetized rats with bilaterally implanted electrodes in the IL were exposed to 1 h constant stimulation of 130 Hz of frequency, 60 μA of constant current intensity and biphasic pulse width of 80 μsec. After a period of baseline recording, local field potentials (LFP) were recorded with formvar-insulated stainless steel electrodes. DBS of the IL increased the power of slow wave (SW, <1.5 Hz) and theta (3-12 Hz) frequencies in the hippocampus and BLA Furthermore, IL DBS caused a precise coupling in different frequency bands between both brain structures. The increases in SW band synchronization in hippocampus and BLA after DBS suggest that these changes may be important for the improvement of depressive behavior. In addition, the augmentation in theta synchrony might contribute to improvement in emotional and cognitive processes.

Sleep and mental disorders: A meta-analysis of polysomnographic research

Investigating sleep in mental disorders has the potential to reveal both disorder-specific and transdiagnostic psychophysiological mechanisms. This meta-analysis aimed at determining the polysomnographic (PSG) characteristics of several mental disorders. Relevant studies were searched through standard strategies. Controlled PSG studies evaluating sleep in affective, anxiety, eating, pervasive developmental, borderline and antisocial personality disorders, attention-deficit-hyperactivity disorder (ADHD), and schizophrenia were included. PSG variables of sleep continuity, depth, and architecture, as well as rapid-eye movement (REM) sleep were considered. Calculations were performed with the "Comprehensive Meta-Analysis" and "R" software. Using random effects modeling, for each disorder and each variable, a separate meta-analysis was conducted if at least 3 studies were available for calculation of effect sizes as standardized means (Hedges' g). Sources of variability, that is, sex, age, and mental disorders comorbidity, were evaluated in subgroup analyses. Sleep alterations were evidenced in all disorders, with the exception of ADHD and seasonal affective disorders. Sleep continuity problems were observed in most mental disorders. Sleep depth and REM pressure alterations were associated with affective, anxiety, autism and schizophrenia disorders. Comorbidity was associated with enhanced REM sleep pressure and more inhibition of sleep depth. No sleep parameter was exclusively altered in 1 condition; however, no 2 conditions shared the same PSG profile. Sleep continuity disturbances imply a transdiagnostic imbalance in the arousal system likely representing a basic dimension of mental health. Sleep depth and REM variables might play a key role in psychiatric comorbidity processes. Constellations of sleep alterations may define distinct disorders better than alterations in 1 single variable. (PsycINFO Database Record

Use of Selective Serotonin Reuptake Inhibitors and Sleep Quality: A Population-Based Study

STUDY OBJECTIVES

Poor sleep is a risk factor for the development and recurrence of depression. Selective serotonin reuptake inhibitor (SSRI) use is consistently associated with good subjective sleep in clinically depressed patient populations. However, studies in the general population are lacking. Our objective was to investigate the association between SSRIs and subjective sleep in a middle-aged and elderly population in a daily practice setting.

METHODS

We included participants from the prospective Rotterdam Study cohort. Participants had up to two subjective sleep measurements assessed with Pittsburgh Sleep Quality Index ([PSQI], number of measurements = 14,770). SSRI use was based on pharmacy records. We assessed the association between SSRIs and PSQI score and its sub-components, with nonusers of any antidepressant as reference. Analyses were, among others, adjusted for presence of depressive symptoms and concurrent psycholeptic drug use.

RESULTS

We included 9,267 participants, average baseline age 66.3 y (standard deviation 10.6), and 57.6% women. SSRI use was significantly associated with a 0.78-point lower PSQI score (95% confidence interval [CI] -1.11; -0.44) which reflects better sleep, compared with non-use. The association was more prominent in continuous SSRI users (-0.71 points, 95% CI -1.18; -0.24). Of the sub-components, SSRIs were associated with 0.70-h longer sleep duration (95% CI 0.56; 0.85), higher sleep quality, higher sleep efficiency, and in contrast more daytime dysfunction.

CONCLUSIONS

SSRI use was associated with better subjective sleep, after adjustment for depressive symptoms and concurrent psycholeptic drug use. This suggests that, in clinical practice in the middle-aged and elderly population, the sleep quality of some persons may benefit from, continued, SSRI use.

Using biomarkers to predict treatment response in major depressive disorder: evidence from past and present studies

Major depressive disorder (MDD) is a heterogeneous condition with a variable response to a wide range of treatments. Despite intensive efforts, no biomarker has been identified to date that can reliably predict response or non-response to any form of treatment, nor has one been identified that can be used to identify those at high risk of developing treatment-resistant depression (ie, non-response to a sequence of treatments delivered for adequate duration and intensity). This manuscript reviews some past areas of research that have proved informative, such as studies using indexes of hypercortisolism or sleep disturbance, and more recent research findings using measures of inflammation and different indicators of regional cortical activation to predict treatment response. It is concluded that, although no method has yet been demonstrated to be sufficiently accurate to be applied in clinical practice, progress has been made. It thus seems likely that—at some point in the not-too-distant future—it will be possible to prospectively identify, at least for some MDD patients, the likelihood of response or non-response to cognitive therapy or various antidepressant medications.

Real-world, open-label study to evaluate the effectiveness of mirtazapine on sleep quality in outpatients with major depressive disorder

INTRODUCTION

The objective of this study was to evaluate the effect of mirtazapine on sleep quality in real-world outpatients with major depressive disorder (MDD).

METHODS

Demographic characteristics of MDD outpatients were collected and the Pittsburgh Sleep Quality Index (PSQI) was assessed before and after treatment.

RESULTS

In 3,924 MDD outpatients after treatment, sleep efficiency was significantly higher (P < 0.001), global PSQI score was significantly lower (P < 0.01), the reduction rates of sleep latency (P < 0.01) and global PSQI score (P < 0.001) were notably higher, and the proportion of using sleep medications (P < 0.05) was significantly lower in the mirtazapine group. In 3,455 MDD outpatients with insomnia after treatment, the reduction of sleep latency (P < 0.001), the prolongation of sleep duration (P < 0.001), and the increase in habitual sleep efficiency (P < 0.001) were more obvious, the reduction rates of sleep latency (P < 0.05) and global PSQI score (P < 0.001) were significantly higher, and the proportion of using sleep medications (P < 0.001) was significantly lower in the mirtazapine group. In 469 MDD outpatients without insomnia after treatment, the reduction of sleep latency (P < 0.05), the increase in sleep duration (P < 0.001) and habitual sleep efficiency (P < 0.001), and the reduction rate of global PSQI score (P < 0.05) were significantly greater in the mirtazapine group.

DISCUSSION

This real-world study suggests that mirtazapine improves sleep quality of MDD outpatients, and decreases the concomitant use of sleep medications.

Manipulating the sleep-wake cycle and circadian rhythms to improve clinical management of major depression

BACKGROUND

Clinical psychiatry has always been limited by the lack of objective tests to substantiate diagnoses and a lack of specific treatments that target underlying pathophysiology. One area in which these twin failures has been most frustrating is major depression. Due to very considerable progress in the basic and clinical neurosciences of sleep-wake cycles and underlying circadian systems this situation is now rapidly changing.

DISCUSSION

The development of specific behavioral or pharmacological strategies that target these basic regulatory systems is driving renewed clinical interest. Here, we explore the extent to which objective tests of sleep-wake cycles and circadian function - namely, those that measure timing or synchrony of circadian-dependent physiology as well as daytime activity and nighttime sleep patterns - can be used to identify a sub-class of patients with major depression who have disturbed circadian profiles.

SUMMARY

Once this unique pathophysiology is characterized, a highly personalized treatment plan can be proposed and monitored. New treatments will now be designed and old treatments re-evaluated on the basis of their effects on objective measures of sleep-wake cycles, circadian rhythms and related metabolic systems.

Insomnia moderates outcome of serotonin-selective reuptake inhibitor treatment in depressed youth

OBJECTIVE

Insomnia is evident in the majority of youth with depression, and is associated with poorer outcomes. There are limited data on the impact of insomnia in response to acute treatment, which is particularly relevant with serotonin-selective reuptake inhibitors, given their tendency to worsen sleep architecture.

METHODS

Three hundred nine children and adolescents (ages 7-18 years) were randomized to fluoxetine (n=157) or placebo (n=152) for 8-9 weeks (Emslie et al.1997, 2002). Substantial insomnia at baseline was defined as a child's depression rating scale-revised [CDRS-R] sleep item ≥ 4. Outcome measures were CDRS-R, response, and remission.

RESULTS

Insomnia was reported in 172/309 (55.7%) youth, and was associated with higher depression severity and greater fatigue, suicidal ideation, physical complaints, and decreased concentration. While response rates were similar in those with or without insomnia overall (51.7% vs. 55.7%), there is a significant difference by age group. Among adolescents, those with insomnia were less likely to respond to fluoxetine (39.2%; 20/51) than those without (65.9%; 27/41; p=0.013), while in children on fluoxetine, those with insomnia were more likely to respond to fluoxetine (69.4%; 25/36) than those without insomnia (41.4%; 12/29; p=0.027). Insomnia did not impact the response to placebo in either age group. Within adolescents, the overall least squares means for CDRS-R total score (across the 8 weeks of treatment) were significantly different between those who had insomnia versus those who did not within the fluoxetine group (43.65 [SE=1.31] vs. 36.58[SE=1.45], F=12.69, df=1, 169, p=0.0005; d=0.82), but not within the placebo group (44.91[SE=1.34] vs. 43.75[SE=1.68], F=0.29, df=1, 179, p=0.591; d=0.15).

CONCLUSIONS

While adolescents reporting substantial insomnia were less likely to respond to antidepressant treatment than those without insomnia, children were more responsive to fluoxetine when they had insomnia. Additional intervention targeting sleep disturbance may be warranted in adolescents.

Clinical relevance of disturbances of sleep and vigilance in major depressive disorder: a review

OBJECTIVE

The primary objective of this article is to provide a concise review of the clinical relevance of sleep and vigilance in major depressive disorder.

DATA SOURCES

PubMed was reviewed (1990-2009) and English-language articles were identified using the key words sleep and depression and sleep and antidepressants. Secondary searches included articles cited in sources identified by the primary search.

STUDY SELECTION

The narrative review provides brief descriptions of the normal physiology of sleep and changes associated with depression, as well as the impact of various treatments on these processes.

DATA SYNTHESIS

Although it has long been known that sleep disturbances are an important characteristic of depression, relatively few studies have been conducted with the newer-generation antidepressants. Neither of the most widely used classes of antidepressants, the selective serotonin reuptake inhibitors and the serotonin-norepinephrine reuptake inhibitors, have particularly beneficial effects on sleep and, among the medications that reliably improve sleep efficiency, including mirtazapine and the tricyclic antidepressants, problems with daytime sedation can offset therapeutic benefit. Despite relatively widespread use, trazodone has not been demonstrated to be an effective and safe hypnotic in patients taking other antidepressants. For many patients, ongoing concomitant treatment with benzodiazepines and related drugs is the preferred option, again without convincing empirical support of longer-term efficacy. Among newer and investigational antidepressants, agomelatine shows promise with respect to both overall safety and effects on insomnia, although possible negative effects on liver function warrant further study.

CONCLUSIONS

Sleep disturbances are a significant aspect of depressive syndromes, and relief of insomnia remains an important unmet need in antidepressant therapeutics. Development of a well-tolerated antidepressant medication that rapidly improves sleep maintenance without daytime sedation is a priority for drug development.

Circadian rhythms and depression: human psychopathology and animal models

Most organisms (including humans) developed daily rhythms in almost every aspect of their body. It is not surprising that rhythms are also related to affect in health and disease. In the present review we present data that demonstrate the evidence for significant interactions between circadian rhythms and affect from both human studies and animal models research. A number of lines of evidence obtained from human and from animal models research clearly demonstrate relationships between depression and circadian rhythms including (1) daily patterns of depression; (2) seasonal affective disorder; (3) connections between circadian clock genes and depression; (4) relationship between sleep disorders and depression; (5) the antidepressant effect of sleep deprivation; (6) the antidepressant effect of bright light exposure; and (7) the effects of antidepressant drugs on sleep and circadian rhythms. The integration of data suggests that the relationships between the circadian system and depression are well established but the underlying biology of the interactions is far from being understood. We suggest that an important factor hindering research into the underlying mechanisms is the lack of good animal models and we propose that additional efforts in that area should be made. One step in that direction could be the attempt to develop models utilizing diurnal animals which might have a better homology to humans with regard to their circadian rhythms. This article is part of a Special Issue entitled 'Anxiety and Depression'.

Prospective associations of insomnia markers and symptoms with depression

Whether insomnia, a known correlate of depression, predicts depression longitudinally warrants elucidation. The authors examined 555 Wisconsin Sleep Cohort Study participants aged 33-71 years without baseline depression or antidepressant use who completed baseline and follow-up overnight polysomnography and had complete questionnaire-based data on insomnia and depression for 1998-2006. Using Poisson regression, they estimated relative risks for depression (Zung scale score > or =50) at 4-year (average) follow-up according to baseline insomnia symptoms and polysomnographic markers. Twenty-six participants (4.7%) developed depression by follow-up. Having 3-4 insomnia symptoms versus none predicted depression risk (age-, sex-, and comorbidity-adjusted relative risk (RR) = 3.2, 95% confidence interval: 1.1, 9.6). After multiple adjustments, frequent difficulty falling asleep (RR = 5.3, 95% confidence interval: 1.1, 27.9) and polysomnographically assessed (upper or lower quartiles) sleep latency, continuity, and duration (RRs = 2.2-4.7; P's < or = 0.05) predicted depression. Graded trends (P-trend < or = 0.05) were observed with increasing number of symptoms, difficulty falling asleep, and difficulty returning to sleep. Given the small number of events using Zung > or =50 (depression cutpoint), a limitation that may bias multivariable estimates, continuous depression scores were analyzed; mean values were largely consistent with dichotomous findings. Insomnia symptoms or markers increased depression risk 2.2- to 5.3-fold. These results support prior findings based on self-reported insomnia and may extend similar conclusions to objective markers. Heightened recognition and treatment of insomnia may prevent subsequent depression.

Wake and sleep EEG provide biomarkers in depression

Both wake and sleep electroencephalogram (EEG) provide biomarkers of depression and antidepressive therapy, respectively. For a long time it is known that EEG activity is altered by drugs. Quantitative EEG analysis helps to delineate effects of antidepressants on brain activity. Cordance is an EEG measure with a superior correlation with regional brain perfusion. Prefrontal quantitative EEG cordance appears to be a predictor of the response to antidepressants. Sleep EEG shows characteristic changes in depression as impaired sleep continuity, desinhibition of REM sleep and changes of nonREM sleep. Elevated REM density (a measure for frequency of rapid eye movements) characterizes an endophenotype in family studies of depression. REM-sleep changes including a more distinct REM rebound after sleep deprivation are found in animal models of depression. Most antidepressants suppress REM sleep in depressed patients, normal controls and laboratory animals. REM suppression appears to be a distinct, but not an absolute requirement for antidepressive effects of a compound. Sleep-EEG variables like REM latency or certain clusters of variables were shown to predict the response to the treatment with a certain antidepressant or even the course of the disorder for several years. Some of these predictive sleep-EEG markers of the longterm course of depression appear to be closely related to hypothalamo-pituitary-adrenocortical system activity.

Conditional corticotropin-releasing hormone overexpression in the mouse forebrain enhances rapid eye movement sleep

Impaired sleep and enhanced stress hormone secretion are the hallmarks of stress-related disorders, including major depression. The central neuropeptide, corticotropin-releasing hormone (CRH), is a key hormone that regulates humoral and behavioral adaptation to stress. Its prolonged hypersecretion is believed to play a key role in the development and course of depressive symptoms, and is associated with sleep impairment. To investigate the specific effects of central CRH overexpression on sleep, we used conditional mouse mutants that overexpress CRH in the entire central nervous system (CRH-COE-Nes) or only in the forebrain, including limbic structures (CRH-COE-Cam). Compared with wild-type or control mice during baseline, both homozygous CRH-COE-Nes and -Cam mice showed constantly increased rapid eye movement (REM) sleep, whereas slightly suppressed non-REM sleep was detected only in CRH-COE-Nes mice during the light period. In response to 6-h sleep deprivation, elevated levels of REM sleep also became evident in heterozygous CRH-COE-Nes and -Cam mice during recovery, which was reversed by treatment with a CRH receptor type 1 (CRHR1) antagonist in heterozygous and homozygous CRH-COE-Nes mice. The peripheral stress hormone levels were not elevated at baseline, and even after sleep deprivation they were indistinguishable across genotypes. As the stress axis was not altered, sleep changes, in particular enhanced REM sleep, occurring in these models are most likely induced by the forebrain CRH through the activation of CRHR1. CRH hypersecretion in the forebrain seems to drive REM sleep, supporting the notion that enhanced REM sleep may serve as biomarker for clinical conditions associated with enhanced CRH secretion.

Affective personality as cognitive-emotional presymptom profiles regulatory for self-reported health predispositions

Three studies that examined the links between affective personality, as constructed from responses to the Positive Affect (PA) and Negative Affect (NA) Scale (PANAS), and individuals' self-report of self-esteem, intrinsic motivation and Beck's Depression Inventory (BDI) depression in high school students and persons in working occupations are described. Self-report estimations of several other neuropsychiatric and psychosocial variables including, the Uppsala Sleep Inventory (USI), the Hospital Anxiety and Depression (HAD) test, Dispositional optimism, Locus of control, the Subjective Stress Experience test (SSE) and the Stress-Energy (SE) test, were also derived. Marked effects due to affective personality type upon somatic and psychological stress, anxiety and depression, self-esteem, internal and external locus of control, optimism, stress and energy, intrinsic motivation, external regulation, identified regulation, major sleep problems, problems falling asleep, and psychophysiological problems were observed; levels of self-esteem, self-motivation and BDI-depression all produced substantial effects on health and well-being. Regression analyses indicated PA was predicted by dispositional optimism (thrice), energy (thrice), and intrinsic motivation, and counter predicted by depression (twice) and stress (twice); and NA by anxiety (twice), stress (twice), psychological stress, identified regulation, BDI depression and psychophysiological problems, and counter predicted by internal locus of control and self-esteem. BDI-depression was predicted by negative affect, major sleep problems and psychophysiological problems (Study III), self-esteem by dispositional optimism and energy, and counter predicted by anxiety, depression and stress (Study I), and intrinsic motivation by dispositional optimism, energy, PA and self-esteem (Study II). These convergent findings are interpreted from a perspective of the cognitive-emotional expressions underlying behavioural or presymptomatic profiles presenting predispositions for health or ill health.

Circadian rhythm disturbances in depression

OBJECTIVE

The aim of this article is to review progress in understanding the mechanisms that underlie circadian and sleep rhythms, and their role in the pathogenesis and treatment of depression.

METHODS

Literature was selected principally by Medline searches, and additional reports were identified based on ongoing research activities in the authors' laboratory.

RESULTS

Many physiological processes show circadian rhythms of activity. Sleep and waking are the most obvious circadian rhythms in mammals. There is considerable evidence that circadian and sleep disturbances are important in the pathophysiology of mood disorders. Depressed patients often show altered circadian rhythms, sleep disturbances, and diurnal mood variation. Chronotherapies, including bright light exposure, sleep deprivation, and social rhythm therapies, may be useful adjuncts in non-seasonal and seasonal depression. Antidepressant drugs have marked effects on circadian processes and sleep.

CONCLUSIONS

Recent progress in understanding chronobiological and sleep regulation mechanisms may provide novel insights and avenues into the development of new pharmacological and behavioral treatment strategies for mood disorders.

Nighttime heart rate and survival in depressed patients post acute myocardial infarction

OBJECTIVES

To determine if: 1) depressed patients with a recent acute myocardial infarction (AMI) have higher nighttime heart rate (HR) than nondepressed patients, and 2) elevated nighttime HR is associated with decreased survival post AMI. Depression is a risk factor for mortality post AMI. It is also associated with sleep disturbances and with elevated HR, which may be more pronounced at night. Resting and 24-hour HR have been found to predict mortality in patient and community samples.

METHODS

Ambulatory electrocardiographic data were obtained from 333 depressed patients and 383 nondepressed patients with recent AMI. They were followed for up to 30 months (median = 24 months).

RESULTS

Depressed patients had higher nighttime HR (70.7 +/- 0.7 versus 67.7 +/- 0.6 beats per minute (bpm); p = .001), and daytime HR (76.4 +/- 0.7 versus 74.2 +/- 0.6 bpm; p = .02) than nondepressed patients, even after adjusting for potential confounds. Depression (hazard ratio (Haz R) = 2.19; p = .02) and nighttime HR (Haz R = 1.03; p = .004), but not daytime HR, predicted survival after adjusting for other major predictors and for each other. The interaction between nighttime HR and depression on survival approached, but did not achieve, significance (p = .08).

CONCLUSIONS

Mean day and nighttime HR values are higher in depressed patients than in nondepressed patients post AMI. Depression and elevated nighttime HR, but not daytime HR, are independent predictors of survival in these patients. Although depressed patients have a higher nighttime HR than nondepressed patients, nighttime HR predicts mortality in both depressed and nondepressed patients.

Depression: relationships to sleep paralysis and other sleep disturbances in a community sample

Sleep disturbances are important correlates of depression, with epidemiologic research heretofore focused on insomnia and sleepiness. This epidemiologic study's aim was to investigate, in a community sample, depression's relationships to other sleep disturbances: sleep paralysis (SP), hypnagogic/hypnopompic hallucinations (HH), cataplexy - considered rapid eye movement-related disturbances - and automatic behavior (AB). Although typical of narcolepsy, these disturbances are prevalent, albeit under-studied, in the population. Cross-sectional analyses (1998-2002), based on Wisconsin Sleep Cohort Study population-based data from 866 participants (mean age 54, 53% male), examined: depression (Zung Self-Rating Depression Scale), trait anxiety (Spielberger State-Trait Anxiety Inventory, STAI-T >or= 75th percentile), and self-reported sleep disturbances. Descriptive sleep data were obtained by overnight polysomnography. Adjusted logistic regression models estimated depression's associations with each (>few times ever) outcome - SP, HH, AB, and cataplexy. Depression's associations with self-reported SP and cataplexy were not explained by anxiety. After anxiety adjustment, severe depression (Zung >or=55), vis-à-vis Zung <50, increased SP odds approximately 500% (P = 0.0008). Depression (Zung >or=50), after stratification by anxiety given an interaction (P = 0.02), increased self-reported cataplexy odds in non-anxious (OR 8.9, P = 0.0008) but not anxious (OR 1.1, P = 0.82) participants. Insomnia and sleepiness seemed only partial mediators or confounders for depression's associations with self-reported cataplexy and SP. Anxiety (OR 1.9, P = 0.04) partially explained depression's (Zung >or=55) association with HH (OR 2.2, P = 0.08). Anxiety (OR 1.6, P = 0.02) was also more related than depression to AB. Recognizing depression's relationships to oft-neglected sleep disturbances, most notably SP, might assist in better characterizing depression and the full range of its associated sleep problems in the population. Longitudinal studies are warranted to elucidate mediators and causality.

Depression and sleep: pathophysiology and treatment

This review examines the relationship between sleep and depression. Most depressive disorders are characterized by subjective sleep disturbances, and the regulation of sleep is intricately linked to the same mechanisms that are implicated in the pathophysiology of depression. After briefly reviewing the physiology and topography of normal sleep, the disturbances revealed in studies of sleep in depression using polysomnographic recordings and neuroimaging assessments are discussed. Next, treatment implications of the disturbances are reviewed at both clinical and neuro-biologic levels. Most antidepressant medications suppress rapid eye movement (REM) sleep, although this effect is neither necessary nor sufficient for clinical efficacy. Effects on patients' difficulties initiating and maintaining sleep are more specific to particular types of antidepressants. Ideally, an effective antidepressant will result in normalization of disturbed sleep in concert with resolution of the depressive syndrome, although few interventions actually restore decreased slow-wave sleep. Antidepressants that block central histamine 1 and serotonin 2 tend to have stronger effects on sleep maintenance, but are also prone to elicit complaints of daytime sedation. Adjunctive treatment with sedative hypnotic medications-primarily potent, shorter-acting benzodiazepine and γ-aminobutyric acid (GABA A)-selective compounds such as zolpidem-are often used to treat associated insomnia more rapidly. Cognitive behavioral therapy and other nonpharmacologic strategies are also helpful.

Cognitive restructuring and EEG in major depression

Techniques based on cognitive therapy and electroencephalography (EEG) were used to investigate the predictive utility of EEG alpha power with regard to mood improvement. Controls and individuals with major depression participated in four EEG recording blocks. Blocks 1 and 4 were resting baselines. During Block 2, Ss were asked to think about their "most troubling life difficulty." Next, Ss were introduced to cognitive views of depression and techniques used in cognitive therapy. For Block 3, Ss were asked to use these methods to think again about their life difficulty. Ss who reported greater post- than pre-intervention happiness (i.e., "Responders") exhibited greater overall cortical activity than Non-responders. Depressed Responders further exhibited a cortical asymmetry of greater right relative to left activity in frontal areas. The predictive utility of EEG is discussed with regard to identifying individuals who show mood improvement following cognitive restructuring.

Affective state and EEG sleep profile in response to rapid tryptophan depletion in recently recovered nonmedicated depressed individuals

BACKGROUND

The current study examines whether a tryptophan-free amino acid drink (TFD) causes a transient mood relapse in unmedicated patients recently recovered from major depression. TFD is thought to reduce cerebral serotonin, a neurotransmitter implicated in depression. Some studies report that TFD reverses the antidepressant and REM-suppression effects of selective serotonin reuptake inhibitors (SSRIs).

METHODS

Following an average of 10 weeks of Cognitive Behavioral Therapy (CBT), 13 recovered patients who achieved 50% or greater reduction on the initial Hamilton Rating Scale of Depression (HRSD) underwent a double-blind challenge with the TFD and a control drink. In order to demonstrate the central physiological effects of the TFD on REM sleep in these patients, all night polygraphic sleep recordings were obtained before and after the TFD and control drink.

RESULTS

Relative to the control drink, TFD decreased REM latency and plasma concentrations of tryptophan but had no statistically significant effect on mood symptoms as measured by the HRSD, Beck Depression Inventory (BDI), and Profile of Mood States (POMS).

LIMITATIONS

High participant attrition, a physiologically active control drink, physical side effects in response to both drinks, and low statistical power may be methodological considerations that limit interpretation of findings.

CONCLUSIONS

The failure to find a transient mood relapse after the TFD may suggest that: (a) nonpharmacological recovery from depression does not occur via serotonergic mechanisms, (b) participant variables may be operating, or (c) CBT alters psychological responses to unfavorable biological states.

Intravenous administration of the neuropeptide galanin has fast antidepressant efficacy and affects the sleep EEG

OBJECTIVE

Recently, we demonstrated that the intravenous administration of the neuropeptide galanin acts on the sleep EEG of healthy young subjects similar to sleep deprivation. As this effect could imply an antidepressive potency we studied the effect of intravenous galanin administration on psychopathology and sleep EEG in patients with depression.

METHODS

Galanin was administered to 10 patients with depression, who were on a stable dose of trimipramine. A placebo controlled double blind randomized design was used. Intravenous boli of galanin in a dose of 4 x 50 microg or placebo were administered hourly between 09:00 and 12:00 h. Galanin or placebo, respectively were administered on 2 days each. The sequence of the galanin or placebo days was randomized, allowing for various crossovers. The Hamilton depression rating scale score (HAMD) was performed 30 min before the first and 30 min after the last injection. The mean of the HAMD change between 08:30 and 12:30 h was chosen as primary efficacy variable. Sleep EEGs were recorded once post placebo treatment and once post verum treatment. In this case, recordings started at 23:00 h and ended at 07:00 h the next morning.

RESULTS

The HAMD-difference between 08:30 and 12:30 h was significantly greater at the days of galanin-treatment compared to placebo-treatment. MANOVA revealed a significant change in sleep-EEG parameters (p < 0.05), mainly due to an increase in REM-latency (p < 0.06).

CONCLUSION

The data provide preliminary evidence for an acute antidepressive efficacy of galanin, probably by a mechanism related to that of therapeutic sleep deprivation.

Electroencephalographic sleep profiles in treatment course and long-term outcome of major depression: association with DEX/CRH-test response

Altered electroencephalographic (EEG) sleep patterns are among the most prominent neurobiological findings in depression. Several of these alterations have been suggested to be associated with an unfavorable long-term outcome. However, the impact of pathological sleep parameters on a more recurrent course of illness or vice versa still warrants clarification. Underlying mechanisms may involve systems known to be related to both sleep regulation and long-term course of depression such as the hypothalamic-pituitary-adrenocortical (HPA) axis. Thus, EEG sleep profiles of patients with depression were examined to determine whether (1) the retrospective clinical course of depression, and (2) the prospective long-term outcome in follow-up are associated with EEG sleep parameters. To elucidate related mechanisms HPA system functioning was evaluated by using the combined DEX/CRH test. Fifteen patients with affective disorders who participated in an earlier controlled antidepressant treatment study over 6 weeks were consecutively enrolled in an exploratory follow-up study. The retrospective analysis revealed that during the acute state of depression predominantly sleep continuity measures were associated with the number of previously experienced episodes. While this relation disappeared during treatment and did not correlate with the prospective course, decreased slow wave sleep variables especially in the first sleep period and increased rapid eye movement density were predictive for the occurrence of recurrences in follow-up and, hence, probably reflect more trait-like markers. Additionally, EEG sleep variables unfavorable for long-term outcome were related to excessive stress hormone response in the DEX/CRH-test. These disturbances may reflect important mechanisms responsible of causing and maintaining the disease process of depression.

Sleep respiratory concomitants of comorbid panic and nightmare complaint in post-traumatic stress disorder

Posttraumatic stress disorder (PTSD) patients with comorbid panic disorder (PD) may express additive symptoms of central fear system disturbance. They endorse elevated levels of sleep and nightmare disturbance [Leskin GA, et al., J Psychiatr Res 2002;36:449-452], and demonstrate movement suppression during laboratory sleep [Woodward SH, et al., Sleep 2002;25:681-688]. We estimated respiratory rate and rate variability separately for rapid-eye movement (REM) and non-rapid-eye movement (NREM) sleep. Subjects were 49 Vietnam combat-related PTSD inpatients (11 with comorbid PD and 38 without) and 15 controls. Computer-based estimates of respiratory rate and variability were derived from 10 to 18 hr of baseline sleep collected over two or three nights. Neither rate nor rate variability distinguished PTSD patients with comorbid PD from those without, or PTSD patients from controls; however, PTSD patients failed to exhibit the expected differences between REM and NREM respiratory rates. Moreover, the difference between REM and NREM respiratory rate was inversely related to a continuous measure of PTSD severity. PTSD patients with trauma-related nightmare complaint exhibited higher sleep respiration rates over both REM and NREM sleep. Conversely, in addition to slowed respiration, nightmare-free patients exhibited reduced respiratory rate variability in REM relative to NREM sleep, which was a reversal of the normal pattern. These finding are discussed in light of known telencephalic regulatory influences upon respiration rate.

Effects of sertraline on sleep architecture in patients with depression

Previous studies indicate that selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, fluvoxamine, citalopram and paroxetine, suppress rapid eye movement sleep, and increased nocturnal arousals. There has been no published report of the impact of sertraline on the sleep of depressed patients. This study examines such effects. Forty-seven patients with major depressive disorder, randomized to double-blind treatment with sertraline or placebo, completed sleep studies before and after 12 weeks of pharmacotherapy. Groups were compared using multivariate analyses of covariance and/or analyses of covariance to examine 4 empirically defined sets of sleep measures. Compared to the placebo-treated group, patients who received sertraline experienced an increase in delta wave sleep in the first sleep cycle and prolonged rapid eye movement (REM) sleep latency. Although, sertraline therapy decreased the average number of REM periods (from 3.86 to 2.40), the activity of both REM period 1 and REM period 2 was significantly increased. Aside from an increase in sleep latency, sertraline therapy was not associated with a worsening of measures of sleep continuity. There was also no significant difference between the groups on a measure of subjective sleepiness. These findings are both similar and different from those observed in previous studies of other SSRIs. The increase in delta sleep ratio and consolidation of REM sleep may have some other clinical implications. However, the generalizability of these findings is limited because of a number of reasons. Further studies are needed to examine the effects of SSRIs in acute treatment of depressed patients with severe insomnia, and the relationship of acute changes and relapse prevention of recurrent depression.

The renin-angiotensin-aldosterone system in patients with depression compared to controls--a sleep endocrine study

BACKGROUND

Hypercortisolism as a sign of hypothamamus-pituitary-adrenocortical (HPA) axis overactivity and sleep EEG changes are frequently observed in depression. Closely related to the HPA axis is the renin-angiotensin-aldosterone system (RAAS) as 1. adrenocorticotropic hormone (ACTH) is a common stimulus for cortisol and aldosterone, 2. cortisol release is suppressed by mineralocorticoid receptor (MR) agonists 3. angiotensin II (ATII) releases CRH and vasopressin from the hypothalamus. Furthermore renin and aldosterone secretion are synchronized to the rapid eyed movement (REM)-nonREM cycle.

METHODS

Here we focus on the difference of sleep related activity of the RAAS between depressed patients and healthy controls. We studied the nocturnal plasma concentration of ACTH, cortisol, renin and aldosterone, and sleep EEG in 7 medication free patients with depression (1 male, 6 females, age: (mean +/-SD) 53.3 +/- 14.4 yr.) and 7 age matched controls (2 males, 5 females, age: 54.7 +/- 19.5 yr.). After one night of accommodation a polysomnography was performed between 23.00 h and 7.00 h. During examination nights blood samples were taken every 20 min between 23.00 h and 7.00 h. Area under the curve (AUC) for the hormones separated for the halves of the night (23.00 h to 3.00 h and 3.00 h to 7.00 h) were used for statistical analysis, with analysis of co variance being performed with age as a covariate.

RESULTS

No differences in ACTH and renin concentrations were found. For cortisol, a trend to an increase was found in the first half of the night in patients compared to controls (p < 0.06). Aldosterone was largely increased in the first (p < 0.05) and second (p < 0.01) half of the night. Cross correlations between hormone concentrations revealed that in contrast to earlier findings, which included only male subjects, in our primarily female sample, renin and aldosterone secretion were not coupled and no difference between patients and controls could be found, suggesting a gender difference in RAAS regulation. No difference in conventional sleep EEG parameters were found in our sample.

CONCLUSION

Hyperaldosteronism could be a sensitive marker for depression. Further our findings point to an altered renal mineralocorticoid sensitivity in patients with depression.

Nocturnal catecholamines and immune function in insomniacs, depressed patients, and control subjects

Insomnia predicts cardiovascular and non-cardiovascular disease mortality. This study evaluated EEG sleep, nocturnal sympathetic activity, and daytime measures of immune function in subjects with primary insomnia (n = 17) and patients with current major depression (n = 14) as compared to controls (n = 31). Insomniacs showed disordered sleep continuity along with nocturnal increases of average levels of circulating norepinephrine and decreases of natural killer cell responses, whereas depressed patients showed declines of natural killer cell activity, but no differences of EEG sleep or nocturnal catecholamines as compared to controls. Impairments of sleep efficiency correlated with nocturnal elevations of norepinephrine in the insomniacs but not in the depressives or controls. These data indicate that insomnia is associated with nocturnal sympathetic arousal and declines of natural immunity, and further support the role of sleep in the regulation of sympathetic nervous and immune system functioning.

Sleep and treatment response in depression: new findings using power spectral analysis

This study examined quantitative measures of sleep electroencephalogram (EEG) and phasic rapid eye movements (REM) as correlates of remission and recovery in depressed patients. To address correlates of remission, pre-treatment EEG sleep studies were examined in 130 women outpatients with major depressive disorder treated with interpersonal psychotherapy (IPT). To address correlates of recovery, baseline and post-treatment EEG sleep studies were examined in 23 women who recovered with IPT alone and 23 women who recovered with IPT+fluoxetine. Outcomes included EEG power spectra during non-rapid eye movement (NREM) sleep and REM sleep and quantitative REMs. IPT non-remitters had increased phasic REM compared with remitters, but no significant differences in EEG power spectra. IPT+fluoxetine recoverers, but not IPT recoverers, showed increases in phasic REM and REM percentage from baseline to recovery. In NREM sleep, the IPT+fluoxetine group showed a decrease in alpha power from baseline to recovery, while the IPT group showed a slight increase. The number of REMs was a more robust correlate of remission and recovery than modeled quantitative EEG spectra during NREM or REM sleep. Quantitative REMs may provide a more direct measure of brainstem function and dysfunction during REM sleep than quantitative sleep EEG measures.

Secondary insomnia: diagnostic challenges and intervention opportunities

The assessment and treatment of secondary insomnia (SI), the most common form of insomnia, are often complicated. Establishing an accompanying disorder as causal rather than comorbid is the key to assessment, but can be difficult even for experienced clinicians. Treatment often focuses on the primary disorder. In many cases, however, there is reason to treat the insomnia directly (insomnia is partially independent, does not respond to treatment of the primary condition, or has been misdiagnosed as SI). Although hypnotic medications are frequently used, behavioral interventions may be the best treatment approach, providing better long-term management of symptoms. Older adults warrant special consideration as age-related illnesses, changes in drug absorption and metabolism, and polypharmacy make them especially susceptible to SI. Recent research suggests successful treatment of insomnia may also relieve the primary disorder and merits follow-up. Future research is also needed on the efficacy of psychological treatment for SI for specific disorders as well as for older adults.

Is psychotherapy an effective treatment for melancholia and other severe depressive states?

The treatment of severe depression with psychotherapy, alone, is controversial. In this paper, we review the historical, conceptual, and empirical contexts of this controversy. In addition to work by others, we review recent work from our institute which has examined the psychobiological substrates of response to treatment in depressive subtypes. We examine the traditional categories that describe severe depressions. The features and psychobiological correlates of melancholia are discussed, as is the relationship between melancholia and aging. Research on treatment of melancholia and other severe depressive states with psychotherapies such as cognitive behavior therapy (CBT) and interpersonal psychotherapy (IPT) is reviewed in detail. We conclude that although some melancholic patients are responsive to IPT or CBT, there is not yet compelling evidence that melancholic patients respond to psychotherapy as well as they do to medications. The potentially mediating effects of hypercortisolism, alterations of sleep neurophysiology, and disturbances of information processing and regional cerebral metabolism represent fertile grounds for future investigation. We discuss the practical implications of the literature reviewed.

Regional brain function, emotion and disorders of emotion

Significant progress has been made in our understanding of the neural substrates of emotion and its disorders. Neuroimaging methods have been used to characterize the circuitry underlying disorders of emotion. Particular emphasis has been placed on the prefrontal cortex, anterior cingulate, parietal cortex, and the amygdala as critical components of the circuitry that may be dysfunctional in both depression and anxiety.

The use of multivariate statistical methods in psychiatry

Multivariate methods such as factor analysis and cluster analysis have been used for many years by psychiatric researchers primarily for investigating the problems of psychiatric diagnosis. In more recent times, the range of multivariate techniques used has been extended as has the number of areas in which they are being applied.