Proposed endophenotypes of dysthymia: evolutionary, clinical and pharmacogenomic considerations

Long-term disability in common mental disorders in Chinese community: evidence from a five-year follow-up study

BACKGROUND

Common mental disorders are general term for mental disorders with high disability rates and significant social burden. The purpose of this study was to determine the degree of long-term disability associated with common mental disorders and to interpret the relationship between common mental disorders and long-term disability.

METHODS

Participants in the 2013 China Mental Health Survey were followed up by telephone between April and June 2018. This study evaluated long-term disability over a five-year period using the World Health Organization's Disability Assessment Schedule 2.0. Poisson regression was used to analyze the relationship between common mental disorders and long-term disability.

RESULTS

A total of 6269 patients were followed up by telephone. In patients with common mental disorders, the prevalence of disability ranged from 7.62% to 43.94%. The long-term disabilities were significantly associated with dysthymic disorder (DD, RR:2.40; 95% CI:1.87-3.03), major depressive disorder (MDD, RR:1.63; 95% CI:1.34-1.98), generalized anxiety disorder (GAD, RR:1.95; 95% CI:1.15-3.09), obsessive-compulsive disorder (OCD, RR:1.68; 95% CI:1.24-2.22) and alcohol use disorder (AUD, RR: 1.42; 95% CI:0.99-1.96).

CONCLUSIONS

In China, common mental disorders raise the risk of long-term disability, and there is a critical need for monitoring patients with DD, MDD, GAD, OCD, and AUD. For improved quality of life and reduced disability levels, more resources need to be dedicated to mental health in the future.

Review of dysthymia and persistent depressive disorder: history, correlates, and clinical implications

Persistent depressive disorder is a chronic mood disorder that is common and often more disabling than episodic major depression. In DSM-5, the term subsumes several chronic depressive presentations, including dysthymia with or without superimposed major depressive episodes, chronic major depression, and recurrent major depression without recovery between episodes. Dysthymia can be difficult to detect in psychiatric and primary care settings until it intensifies in the form of a superimposed major depressive episode. Although information is scarce concerning the cause of persistent depressive disorder including dysthymia, the causation is likely to be multifactorial. In this narrative Review, we discuss current knowledge about the nosology and neurobiological basis of dysthymia and persistent depressive disorder, emphasising a dimensional perspective based on course for further research. We also review new developments in psychotherapy and pharmacotherapy for persistent depressive disorder, and propose a tailored, modular approach to accommodate its multifaceted nature.

From dysthymia to treatment-resistant depression: evolution of a psychopathological construct

Dysthymia is a psychopathological construct historically described and often reconsidered through the centuries. Its first description is dated back to 400 b.C., when Hippocrates proposed his theory about the 'black bile' and the melancholic temperament. The concept of dysthymia (dys-, 'ill', thymia-, 'emotions') has been largely elaborated in the XIX and XX centuries by Burton, Cullen, Schneider, Kretschmer, Akiskal and other authors, and recently re-formulated in the various editions of the modern Diagnostic and Statistical Manual of Mental Disorders under different diagnostic labels: neurotic depression, dysthymic disorder, persistent depressive disorder. Beyond the nosology, dysthymia issues some other challenges, including the need for further research to characterise the peculiar pathophysiological framework of this syndrome (compared with major depressive disorder) and to better define evidences about tailored-treatment options and their effectiveness.

Assessing mood symptoms through heartbeat dynamics: An HRV study on cardiosurgical patients

BACKGROUND

Heart Rate Variability (HRV) is reduced both in depression and in coronary heart disease (CHD) suggesting common pathophysiological mechanisms for the two disorders. Within CHD, cardiac surgery patients (CSP) with postoperative depression are at greater risk of adverse cardiac events. Therefore, CSP would especially benefit from depression early diagnosis. Here we tested whether HRV-multi-feature analysis discriminates CSP with or without depression and provides an effective estimation of symptoms severity.

METHODS

Thirty-one patients admitted to cardiac rehabilitation after first-time cardiac surgery were recruited. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D). HRV features in time, frequency, and nonlinear domains were extracted from 5-min-ECG recordings at rest and used as predictors of "least absolute shrinkage and selection" (LASSO) operator regression model to estimate patients' CES-D score and to predict depressive state.

RESULTS

The model significantly predicted the CES-D score in all subjects (the total explained variance of CES-D score was 89.93%). Also it discriminated depressed and non-depressed CSP with 86.75% accuracy. Seven of the ten most informative metrics belonged to non-linear-domain.

LIMITATIONS

A higher number of patients evaluated also with a structured clinical interview would help to generalize the present findings.

DISCUSSION

To our knowledge this is the first study using a multi-feature approach to evaluate depression in CSP. The high informative power of HRV-nonlinear metrics suggests their possible pathophysiological role both in depression and in CHD. The high-accuracy of the algorithm at single-subject level opens to its translational use as screening tool in clinical practice.

Perceived stress and poly-tobacco product use across adolescence: Patterns of association and gender differences

Perceived stress-an endophenotype indicative of the tendency to appraise stress as frequent, unpredictable and unmanageable-is associated with adolescent cigarette smoking. It is unclear whether this association: (1) extends to alternative tobacco products, like electronic cigarettes and hookah (tobacco water pipe), which are increasingly popular among youth, and (2) differs by gender. In this report, data were drawn from a population-based longitudinal cohort of youth in Southern California. Perceived stress was assessed at baseline (7th or 8th grade; 2010). Electronic cigarette, hookah, combustible cigarette, and cigar use were assessed at a 4-year follow-up (11th or 12th grade; 2014). After adjusting for confounders, polytomous logistic regressions showed that a standardized baseline perceived stress score (M = 0, SD = 1) predicted electronic cigarette, hookah, combustible cigarette, and cigar use and a poly-tobacco use index at the 4-year follow-up in the overall sample. Interactions between perceived stress and gender were also observed (Interaction Ps < 0.05), which demonstrated that the association of perceived stress with tobacco product use and poly-use were stronger in females (ORs for current use range: 1.47 to 1.72) than males (ORs range: 0.93 to 1.31). Adjusting for baseline perceived stress, the change in perceived stress from baseline to follow-up was also positively associated with use and poly-use of most tobacco products in females and in males to some extent. In the current era in which teen use of alternative tobacco products is increasingly common, adolescent tobacco use and poly-use research and prevention strategies should address gender-specific origins of tobacco product use risk and consider perceived stress and other emotional endophenotypes in such risk pathways.

Psychomotor retardation in elderly untreated depressed patients

BACKGROUND

Psychomotor retardation (PR) is one of the core features in depression according to DSM V (1), but also aging in itself causes cognitive and psychomotor slowing. This is the first study investigating PR in relation to cognitive functioning and to the concomitant effect of depression and aging in a geriatric population ruling out contending effects of psychotropic medication.

METHODS

A group of 28 non-demented depressed elderly is compared to a matched control group of 20 healthy elderly. All participants underwent a test battery containing clinical depression measures, cognitive measures of processing speed, executive function and memory, clinical ratings of PR, and objective computerized fine motor skill-tests. Statistical analysis consisted of a General Linear Method multivariate analysis of variance to compare the clinical, cognitive, and psychomotor outcomes of the two groups.

RESULTS

Patients performed worse on all clinical, cognitive, and PR measures. Both groups showed an effect of cognitive load on fine motor function but the influence was significantly larger for patients than for healthy elderly except for the initiation time.

LIMITATIONS

Due to the restrictive inclusion criteria, only a relatively limited sample size could be obtained.

CONCLUSION

With a medication free sample, an additive effect of depression and aging on cognition and PR in geriatric patients was found. As this effect was independent of demand of effort (by varying the cognitive load), it was apparently not a motivational slowing effect of depression.

The categorisation of dysthymic disorder: can its constituents be meaningfully apportioned?

BACKGROUND

Since its introduction in DSM-III, the validity of dysthymia has been debated. Our objective is to further examine the concept of dysthymia in an outpatient sample, and explore whether its constituents can be meaningfully apportioned.

METHODS

318 patients attending the Black Dog Institute Depression Clinic were assessed by the Mini-International Neuropsychiatric Interview, and completed several self-report measures, in addition to a clinical assessment by an Institute psychiatrist. The characteristics of patients with major depressive disorder (MDD), dysthymic disorder and double depression were examined. Latent Class Analysis (LCA) and Latent Profile Analysis (LPA) were then conducted with the aim of detecting distinct classes based on depressive symptomatology and personality domains, respectively. Finally, clinicians' formulations of the study patients were examined.

RESULTS

Depression groups mainly differed on parameters of severity. Although LCA and LPA analyses indicated the presence of distinct classes, these only moderately correlated with the MINI-diagnosed groups. Finally, there was evidence for considerable heterogeneity within clinicians' formulations of dysthymia.

LIMITATIONS

Inadequate sample numbers for various measures limited the power of the LPA and our sample was weighted to patients with a more severe depressive condition which may affect the detection of a distinct 'dysthymic' personality profile.

CONCLUSIONS

Despite employing a variety of techniques, we were unable to obtain a clear homogeneous picture of dysthymia. Rather, there was evidence for a distinct heterogeneity in clinician-derived diagnoses. These findings allude to the questionable discriminant validity of dysthymia and may encourage future research and discussion on this important topic.

Study of neurocognitive endophenotypes in drug-naïve obsessive-compulsive disorder patients, their first-degree relatives and healthy controls

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a debilitating heritable neuropsychiatric condition. Attempts to delineate genetic contributions in OCD have met with limited success, with an ongoing search for neurocognitive endophenotypes. In this study, an attempt has been made to study and compare the neurocognitive functioning of patients with OCD, their first-degree relatives (FDRs) and healthy controls.

METHOD

A cross-sectional design study was carried out with thirty dyads of patients with OCD, their FDRs and thirty matched healthy controls and screened using Mini International Neuropsychiatric Interview, Verbal Adult Intelligence Scale, Yale Brown Obsessive-Compulsive Scale, Montgomery Åsberg Depression Rating Scale, International Personality Disorder Examination (Anankastic personality scale).Tests of National Institute of Mental Health and Neurosciences Neuropsychological Battery were used to assess domains of attention, verbal memory, visual memory, set-shifting, response inhibition, planning and visuoconstructive abilities. spss version 14.0 was used for descriptive and analytical data analysis.

RESULTS

There were no statistically significant differences between patients with OCD and their FDRs on neurocognitive domains of delayed verbal recall, set-shifting, response inhibition and visuoconstructive abilities (P > 0.05) which were impaired compared with healthy controls. Significant differences (P < 0.05) on domains of attention, planning time and visual memory were noted between FDRs and patients.

CONCLUSION

The present study supports set-shifting and inhibitory control and proposes visuoconstructive abilities and delayed verbal recall as potential endophenotypes for OCD.

Convergent functional genomic studies of ω-3 fatty acids in stress reactivity, bipolar disorder and alcoholism

Omega-3 fatty acids have been proposed as an adjuvant treatment option in psychiatric disorders. Given their other health benefits and their relative lack of toxicity, teratogenicity and side effects, they may be particularly useful in children and in females of child-bearing age, especially during pregnancy and postpartum. A comprehensive mechanistic understanding of their effects is needed. Here we report translational studies demonstrating the phenotypic normalization and gene expression effects of dietary omega-3 fatty acids, specifically docosahexaenoic acid (DHA), in a stress-reactive knockout mouse model of bipolar disorder and co-morbid alcoholism, using a bioinformatic convergent functional genomics approach integrating animal model and human data to prioritize disease-relevant genes. Additionally, to validate at a behavioral level the novel observed effects on decreasing alcohol consumption, we also tested the effects of DHA in an independent animal model, alcohol-preferring (P) rats, a well-established animal model of alcoholism. Our studies uncover sex differences, brain region-specific effects and blood biomarkers that may underpin the effects of DHA. Of note, DHA modulates some of the same genes targeted by current psychotropic medications, as well as increases myelin-related gene expression. Myelin-related gene expression decrease is a common, if nonspecific, denominator of neuropsychiatric disorders. In conclusion, our work supports the potential utility of omega-3 fatty acids, specifically DHA, for a spectrum of psychiatric disorders such as stress disorders, bipolar disorder, alcoholism and beyond.

Psychomotor retardation in depression: biological underpinnings, measurement, and treatment

Psychomotor retardation is a long established component of depression that can have significant clinical and therapeutic implications for treatment. Due to its negative impact on overall function in depressed patients, we review its biological correlates, optimal methods of measurement, and relevance in the context of therapeutic interventions. The aim of the paper is to provide a synthesis of the literature on psychomotor retardation in depression with the goal of enhanced awareness for clinicians and researchers. Increased knowledge and understanding of psychomotor retardation in major depressive disorder may lead to further research and better informed diagnosis in regards to psychomotor retardation. Manifestations of psychomotor retardation include slowed speech, decreased movement, and impaired cognitive function. It is common in patients with melancholic depression and those with psychotic features. Biological correlates may include abnormalities in the basal ganglia and dopaminergic pathways. Neurophysiologic tools such as neuroimaging and transcranial magnetic stimulation may play a role in the study of this symptom in the future. At present, there are three objective scales to evaluate psychomotor retardation severity. Studies examining the impact of psychomotor retardation on clinical outcome have found differential results. However, available evidence suggests that depressed patients with psychomotor retardation may respond well to electroconvulsive therapy (ECT). Current literature regarding antidepressants is inconclusive, though tricyclic antidepressants may be considered for treatment of patients with psychomotor retardation. Future work examining this objective aspect of major depressive disorder (MDD) is essential. This could further elucidate the biological underpinnings of depression and optimize its treatment.

Mindscape: a convergent perspective on life, mind, consciousness and happiness

What are mind, consciousness and happiness, in the fundamental context of life? We propose a convergent perspective (coupling evolutionary biology, genomics, neurobiology and clinical medicine) that could help us better understand what life, mind, consciousness and happiness are, as well as provides empirically testable practical implications.

Toward a functional neuroanatomy of dysthymia: a functional magnetic resonance imaging study

BACKGROUND

Dysthymia is a common mood disorder. Recent studies have confirmed the neurobiological and treatment response overlap of dysthymia with major depression. There are no previous published studies of functional magnetic resonance imaging (fMRI) in dysthymia.

METHOD

fMRI was used to compare neural processing of 17 unmedicated dysthymic patients with 17 age, sex, and education-matched control subjects in a mood induction paradigm using the International Affective Pictures System (IAPS).

RESULTS

Using a random effects analysis to compare the groups, the results revealed that the dysthymic patients had significantly reduced activation in the dorsolateral prefrontal cortex compared to controls. The dysthymic patients exhibited increased activation in the amygdala, anterior cingulate and insula compared to controls and these differences were more evident when processing negative than positive images.

LIMITATIONS

This study included both early and late subtypes of dysthymia, and participants were only imaged at one time point, which may limit the generalizability of the results.

CONCLUSIONS

The findings suggest the involvement of the prefrontal cortex, anterior cingulate, amygdala, and insula in the neural circuitry underlying dysthymia. It is suggested that altered activation in some of these neural regions may be a common substrate for depressive disorders in general while others may relate specifically to symptom characteristics and the chronic course of dysthymia. These findings are particularly striking given the history of this deceptively mild disorder which is still confused by some with character pathology.

Phenotyping psychosis: room for neurocomputational and content-dependent cognitive endophenotypes?

INTRODUCTION

The endophenotype research strategy aims at reducing complex clinical phenomena to reveal a more tractable mapping to underlying genes. Cognitive dysfunctions have been widely pursued as target endophenotype in schizophrenia. We critically discuss the promise and limitations of this approach.

METHODS

Relevant theoretical and empirical issues on genes and behaviour, neurocognitive structure and psychopathology were selectively reviewed and discussed.

RESULTS

Some important inherent limitations of the current cognitive endophenotype approach were identified. These include reliance on (1) classic neuropsychology; (2) deficit measures; and (3) a general information processing approach with the use of content-independent, neutral stimuli. As a result, many current cognitive endophenotypes are likely to overlap and converge with general cognitive impairments, which may be shared with other disorders.

CONCLUSIONS

We propose three novel directions for further psychosis endophenotype research: (1) in addition to such content-independent computational processes, which operate in a similar way regardless of the stimuli, it is important to consider the potential roles of "content-dependent endophenotypes", which operate on different stimuli in consistently different manners. Advances in cognitive studies suggest there may be evolutionarily important aspects of cognition which are content-dependent. We propose that both content-independent and content-dependent processes should be addressed in psychosis research. (2) In line with the emphasis on content, close attention should be paid to the study of "psychopathological endophenotypes" in addition to cognitive endophenotypes. (3) "Neurocomputational endophenotypes" may be defined by parsing cognitive processes into "subsystems" with specific computational processing algorithms and considering key computational parameters suggested from these models. These potential "neurocomputational endophenotypes" (such as neuronal noise, synaptic learning algorithms) are potentially intermediate variables located between the levels of cognition and neurobiology.

Convergent functional genomics of genome-wide association data for bipolar disorder: comprehensive identification of candidate genes, pathways and mechanisms

Given the mounting convergent evidence implicating many more genes in complex disorders such as bipolar disorder than the small number identified unambiguously by the first-generation Genome-Wide Association studies (GWAS) to date, there is a strong need for improvements in methodology. One strategy is to include in the next generation GWAS larger numbers of subjects, and/or to pool independent studies into meta-analyses. We propose and provide proof of principle for the use of a complementary approach, convergent functional genomics (CFG), as a way of mining the existing GWAS datasets for signals that are there already, but did not reach significance using a genetics-only approach. With the CFG approach, the integration of genetics with genomics, of human and animal model data, and of multiple independent lines of evidence converging on the same genes offers a way of extracting signal from noise and prioritizing candidates. In essence our analysis is the most comprehensive integration of genetics and functional genomics to date in the field of bipolar disorder, yielding a series of novel (such as Klf12, Aldh1a1, A2bp1, Ak3l1, Rorb, Rora) and previously known (such as Bdnf, Arntl, Gsk3b, Disc1, Nrg1, Htr2a) candidate genes, blood biomarkers, as well as a comprehensive identification of pathways and mechanisms. These become prime targets for hypothesis driven follow-up studies, new drug development and personalized medicine approaches.

Territory, Rank and Mental Health: The History of an Idea

We trace the development of ideas about the relation of mood to social rank and territory. We suggest that elevated mood enabled a person to rise in rank and cope with the increased activities and responsibilities of a leadership role, while depressed mood enabled a person to accept low rank and to forego the rewards associated with high rank. This led to the concept of a trio of agonist/investor strategy sets, each consisting of escalating and de-escalating strategies, one set at each of the three levels of the triune forebrain. Depressed mood can be seen as a de-escalating (appeasement) strategy at the lowest (reptilian) level; this should facilitate de-escalation at the highest (rational) level, but sometimes this rational level de-escalation is blocked (e.g., by stubbornness, courage, pride or ambition) and then clinical depression may ensue. These evolved psychobiological mechanisms survived the partial transition from agonistic to prestige competition. We discuss difficulties which have arisen with our ideas, and their implications for clinical work and research.

Polypharmacy in oligopopulations: what psychiatric genetics can teach biological psychiatry

Psychiatric genetics and genomics have made major strides in recent years. Some of that knowledge has yet to permeate in the clinical practice of biological psychiatry. The example of cancer-genetics, biology and clinical treatments may be profitable in terms of accelerating translational integration in psychiatry. We propose that current developments in genetics and genomics point to an Early Low-Dose Rational Polypharmacy in Oligopopulations model for psychiatric pharmacotherapy.

PhenoChipping of psychotic disorders: a novel approach for deconstructing and quantitating psychiatric phenotypes

Psychiatric phenotypes as currently defined are primarily the result of clinical consensus criteria rather than empirical research. We propose, and present initial proof of principle for, a novel approach to characterizing psychiatric phenotypes. We have termed our approach PhenoChipping, by analogy with, and borrowing paradigms and tools from, gene expression microarray studies (GeneChipping). A massive parallel profiling of cognitive and affective state is done with a PhenoChip composed of a battery of existing and new quantitative psychiatric rating scales, as well as hand neuromotor measures. We present preliminary data from 104 subjects, 72 with psychotic disorders (bipolar disorder-41, schizophrenia-17, schizoaffective disorder-14), and 32 normal controls. Microarray data analysis software and visualization tools were used to investigate: 1. relationships between phenotypic items ("phenes"), including with objective motor measures, and 2. relationships between subjects. Our analyses revealed phenotypic overlap among, as well as phenotypic heterogeneity within, the three major psychotic disorders studied. This approach may be useful in helping us move beyond current diagnostic classifications, and suggests a combinatorial building-block (Lego-like) structure underlies psychiatric syndromes. The adaptation of microarray informatic tools for phenotypic analysis readily facilitates direct integration with gene expression profiling of lymphocytes in the same individuals, a strategy for molecular biomarker identification. Empirically derived clusterings of (endo)phenotypes and of patients will better serve genetic, pharmacological, and imaging research, as well as clinical practice.

The 5HTTLPR polymorphism of the serotonin transporter gene is associated with affective temperaments as measured by TEMPS-A

BACKGROUND

Increasing evidence supports the notion of a continuum between affective temperaments and major mood disorders, suggesting that these temperament types represent the subclinical manifestations of affective disorders and often present an increased vulnerability for these diseases.

METHODS

The Hungarian rendition of the full-scale 110-item version of the TEMPS-A questionnaire and 5HTTLPR genotype was investigated in a sample of 139 unrelated Caucasian females with no current or lifetime Axis I psychiatric disorders.

RESULTS

A significant association was found between the s allele and the TEMPS scores of the depressive, anxious, irritable, and particularly the cyclothymic temperaments; no such association emerged with respect to the hyperthymic temperament.

LIMITATION

The database is entirely female. Given that the hyperthymic type predominates in males, our results could have been different if men were included in our sample.

CONCLUSIONS

Our results are in good agreement with earlier studies reporting a strong association between the s allele of the 5HTTLPR and major as well as subthreshold forms of depression, and extend this association to the normative temperament level. Indeed, these temperaments might best be regarded as proximate behavioural endophenotypes. Our data raise the provocative possibility that the genetic potential for mood episodes lies in these temperaments. Further studies are needed to delineate the role of gender in the associations under consideration, as well as to investigate the genetic background of the hyperthymia-mania part of the affective spectrum. Given that affective temperaments are widely distributed in the general population, the strategy employed by us is of potential public health significance in terms of detecting individuals in the community at risk for affective spectrum disorders.

Psychiatric endophenotypes and the development of valid animal models

Endophenotypes are quantifiable components in the genes-to-behaviors pathways, distinct from psychiatric symptoms, which make genetic and biological studies of etiologies for disease categories more manageable. The endophenotype concept has emerged as a strategic tool in neuropsychiatric research. This emergence is due to many factors, including the modest reproducibility of results from studies directed toward etiologies and appreciation for the complex relationships between genes and behavior. Disease heterogeneity is often guaranteed, rather than simplified, through the current diagnostic system; inherent benefits of endophenotypes include more specific disease concepts and process definitions. Endophenotypes can be neurophysiological, biochemical, endocrine, neuroanatomical, cognitive or neuropsychological. Heritability and stability (state independence) represent key components of any useful endophenotype. Importantly, they characterize an approach that reduces the complexity of symptoms and multifaceted behaviors, resulting in units of analysis that are more amenable to being modeled in animals. We discuss the benefits of more direct interpretation of clinical endophenotypes by basic behavioral scientists. With the advent of important findings regarding the genes that predispose to psychiatric illness, we are at an important crossroads where, without anthropomorphizing, animal models may provide homologous components of psychiatric illness, rather than simply equating to similar (loosely analogized) behaviors, validators of the efficacy of current medications or models of symptoms. We conclude that there exists a need for increased collaboration between clinicians and basic scientists, the result of which should be to improve diagnosis, classification and treatment on one end and to increase the construct relevance of model organisms on the other.

Genomic studies of mood disorders -- the brain as a muscle?

Recent genomic studies showing abnormalities in the fibroblast growth factor system in the postmortem brains of people with major depressive disorder support previous indications of a role for growth factors in mood disorders. Similar molecular pathways, volumetric changes, and the effects of exercise on mood suggest a superficial analogy, and perhaps a deeper relationship, between muscle and brain functioning.

No psychomotor slowing in fine motor tasks in dysthymia

INTRODUCTION

Few studies using objective and sensitive measuring techniques have investigated whether psychomotor retardation (PR), an important symptom of a major depressive disorder (MDD), is also present in dysthymic patients. In this study, the following questions were addressed: (1) is PR also prevalent in dysthymia? (2) If so, is the PR cognitive or motor in nature? And (3) does the nature and degree of the PR in patients with dysthymia differ from the PR in MDD patients found in earlier studies?

METHODS

PR was measured by comparing the, digitally recorded, fine motor performance of 20 unmedicated dysthymic inpatients (mean age: 33) and 32 controls on copying and drawing tasks. In addition, the performance of the dysthymic patients was compared to the performance results of 32 unmedicated MDD inpatients collected in an earlier study.

RESULTS

The dysthymic patients were not slower than the controls in performing the fine motor tasks: neither initiation time (IT) nor movement time (MT) were prolonged. As expected, the MDD patients did show significantly longer ITs and MTs in all tasks compared to the controls. On the clinical Salpetriere Retardation Rating Scale (SRRS), the dysthymic patients had high scores on mainly subjective cognitive items like concentration and memory complaints.

LIMITATIONS

The dysthymic patients had significantly less severe forms of depression compared to the MDD patients. As dysthymia, by definition, is a less severe form of depression we could not examine whether PR would manifest itself in severely depressed dysthymic patients, as is the case in certain MDD patients.

CONCLUSION

In this study, no objective evidence was found for PR in dysthymic patients during fine motor tasks. PR may be used to differentiate between dysthymia and MDD.

Evolutionary aspects of anxiety disorders

Danger and harm are avoided by strategic decisions made at all three levels of the triune forebrain: rational (neomammalian), emotional (paleomammalian), and instinctive (reptilian). This applies also to potential harm from conspecifics, which leads to a choice between escalating and de-escalating strategies. Anxiety is a component of de-escalating strategies mediated by the paleomammalian and reptilian forebrains. When the neomammalian (rational) brain fails to deal with the threat of conspecific danger, these more primitive de-escalating strategies may be activated and may present as anxiety disorders. The capacity for concealment of anxiety and other forms of negative affect has also evolved, and excessive concealment may lead to psychopaihology by breaking the negative feedback loop of excessive motivation, leading to impaired performance, leading to signals of distress, and leading to reduced exhortation to succeed on the part of parents and teachers; this situation is illustrated by a model based on the Yerkes-Dodson law.

Spectrum and nosology: implications for DSM-V

The authors attempt to show similarities and differences between a spectrum and the DSM-IV perspective in how psychopathology is best represented to clinicians and clinical researchers. Subthreshold symptoms are given little or no attention in DSM; noncriterion symptoms are given none at all. Not otherwise specified disorders may be a widely used category in DSM-IV, but in a spectrum diagnosis there is no similar designation, because use of the whole spectrum of symptoms is possible. Although a DSM-IV categorical disorder may not be the best representation of psychopathology, it is clearly defined and is efficient for the purposes of communication and labeling. Both systems of nosology are essentially atheoretical; comorbidity exists in both, although to a lesser degree in some spectrum models. Data are summarized that clearly demonstrate the need for designers of DSM-V to create a nosology that is, at least in part, dimensional.

Finding genes for bipolar disorder in the functional genomics era: from convergent functional genomics to phenomics and back

Psychiatric genetics, while promising to unravel the mechanisms of psychiatric disorders, has proven to be a challenging field. Psychiatric disorders, like other common genetic traits, are complex and heterogeneous. Psychiatric genetics has also suffered from a lack of quantifiable, biology-based phenotypes. However, the field is currently at an opportune moment. The work of various investigators is on the verge of paying rich dividends. Efforts at positional cloning are being greatly accelerated by the fruits of the Human Genome Project. New tools of functional genomics, such as expression profiling and proteomics, are being applied to animal models. These two methods can complement each other in an approach we have termed convergent functional genomics. Lastly, improvements in the measurement of biologically distinct endophenotypes--or phenomic--will lead to a better understanding of the mapping of genes to phenotypes in both animal and human systems.