Showing papers by "Columbia University published in 1992"

A survey of image registration techniques

Abstract: Registration is a fundamental task in image processing used to match two or more pictures taken, for example, at different times, from different sensors, or from different viewpoints. Virtually all large systems which evaluate images require the registration of images, or a closely related operation, as an intermediate step. Specific examples of systems where image registration is a significant component include matching a target with a real-time image of a scene for target recognition, monitoring global land usage using satellite images, matching stereo images to recover shape for autonomous navigation, and aligning images from different medical modalities for diagnosis.Over the years, a broad range of techniques has been developed for various types of data and problems. These techniques have been independently studied for several different applications, resulting in a large body of research. This paper organizes this material by establishing the relationship between the variations in the images and the type of registration techniques which can most appropriately be applied. Three major types of variations are distinguished. The first type are the variations due to the differences in acquisition which cause the images to be misaligned. To register images, a spatial transformation is found which will remove these variations. The class of transformations which must be searched to find the optimal transformation is determined by knowledge about the variations of this type. The transformation class in turn influences the general technique that should be taken. The second type of variations are those which are also due to differences in acquisition, but cannot be modeled easily such as lighting and atmospheric conditions. This type usually effects intensity values, but they may also be spatial, such as perspective distortions. The third type of variations are differences in the images that are of interest such as object movements, growths, or other scene changes. Variations of the second and third type are not directly removed by registration, but they make registration more difficult since an exact match is no longer possible. In particular, it is critical that variations of the third type are not removed. Knowledge about the characteristics of each type of variation effect the choice of feature space, similarity measure, search space, and search strategy which will make up the final technique. All registration techniques can be viewed as different combinations of these choices. This framework is useful for understanding the merits and relationships between the wide variety of existing techniques and for assisting in the selection of the most suitable technique for a specific problem.

The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description.

Abstract: • The history, rationale, and development of the Structured Clinical Interview for DSM-III-R (SCID) is described. The SCID is a semistuctured interview for making the major Axis I DSM-III-R diagnoses. It is administered by a clinician and includes an introductory overview followed by nine modules, seven of which represent the major axis I diagnostic classes. Because of its modular construction, it can be adapted for use in studies in which particular diagnoses are not of interest. Using a decision tree approach, the SCID guides the clinician in testing diagnostic hypotheses as the interview is conducted. The output of the SCID is a record of the presence or absence of each of the disorders being considered, for current episode (past month) and for lifetime occurrence.

Reversible multiple time scale molecular dynamics

Abstract: The Trotter factorization of the Liouville propagator is used to generate new reversible molecular dynamics integrators This strategy is applied to derive reversible reference system propagator algorithms (RESPA) that greatly accelerate simulations of systems with a separation of time scales or with long range forces The new algorithms have all of the advantages of previous RESPA integrators but are reversible, and more stable than those methods These methods are applied to a set of paradigmatic systems and are shown to be superior to earlier methods It is shown how the new RESPA methods are related to predictor–corrector integrators Finally, we show how these methods can be used to accelerate the integration of the equations of motion of systems with Nose thermostats

The Crisis in Antibiotic Resistance

Abstract: The synthesis of large numbers of antibiotics over the past three decades has caused complacency about the threat of bacterial resistance. Bacteria have become resistant to antimicrobial agents as a result of chromosomal changes or the exchange of the exchange of genetic material via plasmids and transposons. Streptococcus pneumoniae, Streptococcus pyogenes, and staphylococci, organisms that cause respiratory and cutaneous infections, and members of the Enterobacteriaceae and Pseudomonas families, organisms that cause diarrhea, urinary infection, and sepsis, are now resistant to virtually all of the older antibiotics. The extensive use of antibiotics in the community and hospitals has fueled this crisis. Mechanisms such as antibiotic control programs, better hygiene, and synthesis of agents with improved antimicrobial activity need to be adopted in order to limit bacterial resistance.

Nonintrusive appliance load monitoring

Abstract: A nonintrusive appliance load monitor that determines the energy consumption of individual appliances turning on and off in an electric load, based on detailed analysis of the current and voltage of the total load, as measured at the interface to the power source is described. The theory and current practice of nonintrusive appliance load monitoring are discussed, including goals, applications, load models, appliance signatures, algorithms, prototypes field-test results, current research directions, and the advantages and disadvantages of this approach relative to intrusive monitoring. >

Wavelets and filter banks: theory and design

Abstract: The wavelet transform is compared with the more classical short-time Fourier transform approach to signal analysis. Then the relations between wavelets, filter banks, and multiresolution signal processing are explored. A brief review is given of perfect reconstruction filter banks, which can be used both for computing the discrete wavelet transform, and for deriving continuous wavelet bases, provided that the filters meet a constraint known as regularity. Given a low-pass filter, necessary and sufficient conditions for the existence of a complementary high-pass filter that will permit perfect reconstruction are derived. The perfect reconstruction condition is posed as a Bezout identity, and it is shown how it is possible to find all higher-degree complementary filters based on an analogy with the theory of Diophantine equations. An alternative approach based on the theory of continued fractions is also given. These results are used to design highly regular filter banks, which generate biorthogonal continuous wavelet bases with symmetries. >

Frequency domain measures of heart period variability and mortality after myocardial infarction.

Abstract: BACKGROUNDWe studied 715 patients 2 weeks after myocardial infarction to establish the associations between six frequency domain measures of heart period variability (HPV) and mortality during 4 ye...

Optimizing the use of information: strategic control of activation of responses.

Abstract: Recent studies indicate that subjects may respond to visual information during either an early parallel phase or a later focused phase and that the selection of the relevant phase is data driven. Using the noise-compatibility paradigm, we tested the hypothesis that this selection may also be strategic and context driven. At least part of the interference effect observed in this paradigm is due to response activation during the parallel-processing phase. We manipulated subjects' expectancies for compatible and incompatible noise in 4 experiments and effectively modulated the interference effect. The results suggest that expectancies about the relative utility of the information extracted during the parallel and focused phases determine which phase is used to activate responses.

Transnationalism: A New Analytic Framework for Understanding Migration

Abstract: Our earlier conceptions of immigrant and migrant n o longer suffice. The word immigrant evokes images of permanent rupture, of the uprooted, the abandonment of old patterns and the painful learning of a new language and culture. Now, a new kind of migrating population is emerging, composed of those whose networks, activities and patterns of life encompass both their host and home societies. Their lives cut across national boundaries and bring two societies into a single social field. In this book we argue that a new conceptualization is needed in order to come to terms with the experience and consciousness of this new migrant population. We call this new conceptualization, “transnationalism,” and describe the new type of migrants as transmigrants. We have defined transnationalism as the processes by which immigrants build social fields that link together their country of origin and their country of settlement. Immigrants who build such social fields are designated “transmigrants.” Transmigrants develop and maintain multiple relationsfamilial, economic, social, organizational, religious, and political that span borders. Transmigrants take actions, make decisions, and feel concerns, and develop identities within social net-

Discrepancy between Self-Reported and Actual Caloric Intake and Exercise in Obese Subjects

Abstract: Background and Methods. Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet — low total energy expenditure and underreporting of caloric intake — in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance. Results. Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic...

Socioeconomic status and psychiatric disorders: The causation-selection issue.

Abstract: Are inverse relations between psychiatric disorders and socioeconomic status due more to social causation (adversity and stress) or social selection (downward mobility of genetically predisposed)? This classical epidemiological issue is tested by focusing on ethnic status in relation to socioeconomic status. Ethnic status cannot be an effect of disorder because it is present at birth whereas socioeconomic status depends on educational and occupational attainment. A birth cohort sample of 4914 young, Israel-born adults of European and North African background was selected from the country's population register, screened, and diagnosed by psychiatrists. Results indicate that social selection may be more important for schizophrenia and that social causation may be more important for depression in women and for antisocial personality and substance use disorders in men.

Revising axis V for DSM-IV: a review of measures of social functioning.

Abstract: Objective Axis V, which uses the Global Assessment of Functioning Scale in the multiaxial system of DSM-III-R, is under review for DSM-IV. This article examines what is known about axis V and selectively reviews the literature on measures of social functioning to identify potential alternatives to the Global Assessment of Functioning Scale. Method About 25 studies on the use, reliability, and validity of axis V in DSM-III and DSM-III-R are reviewed. In addition, nearly 30 measures of social functioning are reviewed and analyzed as potential substitutes for the Global Assessment of Functioning Scale. The analysis focuses on the strengths and weaknesses of each measure for assessing functioning on axis V. Results Axis V measures are modestly reliable and valid but not widely used. The authors identify and discuss two particular limitations of the Global Assessment of Functioning Scale: 1) the combination of measures of symptoms and measures of social functioning on a single axis and 2) the exclusion of physical impairments from the rating of functioning. Conclusions None of the measures of social functioning reviewed is clearly superior to the Global Assessment of Functioning Scale for use on axis V. A modified version of the Global Assessment of Functioning Scale, separating the measures of social and occupational functioning from the measures of symptoms and psychological functioning, is proposed for field testing, along with a new set of instructions permitting the rating of limitations due to both physical and mental impairments.

The concept of mental disorder: On the boundary between biological facts and social values.

Abstract: Although the concept of mental disorder is fundamental to theory and practice in the mental health field, no agreed on and adequate analysis of this concept currently exists. I argue that a disorder is a harmful dysfunction, wherein harmful is a value term based on social norms, and dysfunction is a scientific term referring to the failure of a mental mechanism to perform a natural function for which it was designed by evolution. Thus, the concept of disorder combines value and scientific components. Six other accounts of disorder are evaluated, including the skeptical antipsychiatric view, the value approach, disorder as whatever professionals treat, two scientific approaches (statistical deviance and biological disadvantage), and the operational definition of disorder as "unexpectable distress or disability" in the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987). The harmful dysfunction analysis is shown to avoid the problems while preserving the insights of these other approaches.

Stages of progression in drug involvement from adolescence to adulthood: further evidence for the gateway theory.

Abstract: Sequential stages of involvement in alcohol and/or cigarettes, marijuana, other illicit drugs and medically prescribed psychoactive drugs from adolescence to adulthood are investigated in a longitudinal cohort that has been followed from ages 15 to 35. Alternative models of progression are tested for their goodness of fit. Four stages are identified: that of legal drugs, alcohol or cigarettes; marijuana; illicit drugs other than marijuana; and medically prescribed drugs. Whereas progression to illicit drugs among men is dependent upon prior use of alcohol, among women either cigarettes or alcohol is a sufficient condition for progression to marijuana. Age of onset and frequency of use at a lower stage of drug use are strong predictors of further progression.

Petrological systematics of mid-ocean ridge basalts: Constraints on melt generation beneath ocean ridges

Abstract: Mid-ocean ridge basalts (MORB) are a consequence of pressure-release melting beneath ocean ridges, and contain much information concerning melt formation, melt migration and heterogeneity within the upper mantle. MORB major element chemical systematics can be divided into global and local aspects, once they have been corrected for low pressure fractionation and interlaboratory biases. Regional average compositions for ridges unaffected by hot spots ("normal" ridges) can be used to define the global correlations among normalized Na20, FeO, TiO2 and Si02 contents, CaO/Al 203 ratios, axial depth and crustal thickness. Back-arc basins show similar correlations, but are offset to lower FeO and TiO2 contents. Some hot spots, such as the Azores and Galapagos, disrupt the systematics of nearby ridges and have the opposite relationships between FeO, Na 20 and depth over distances of 1000 km. Local variations in basalt chemistry from slowand fast-spreading ridges are distinct from one another. On slow-spreading ridges, correlations among the elements cross the global vector of variability at a high angle. On the fast-spreading East Pacific Rise (EPR), correlations among the elements are distinct from both global and slow-spreading compositional vectors, and involve two components of variation. Spreading rate does not control the global correlations, but influences the standard deviations of axial depth, crustal thickness, and MgO contents of basalts. Global correlations are not found in very incompatible trace elements, even for samples far from hot spots. Moderately compatible trace elements for normal ridges, however, correlate with the major elements. Trace element systematics are significantly different for the EPR and the mid-Atlantic Ridge (MAR). Normal portions of the MAR are very depleted in REE, with little variability; hot spots cause large long wavelength variations in REE abundances. Normal EPR basalts are significantly more enriched than MAR basalts from normal ridges, and still more enriched basalts can erupt sporadically along the entire length of the EPR. This leads to very different histograms of distribution for the data sets as a whole, and a very different distribution of chemistry along strike for the two ridges. Despite these differences, the mean Ce/Sm ratios from the two ridges are identical. Existing methods for calculating the major element compositions of mantle melts [Klein and Langmuir, 1987; McKenzie and Bickle, 1988; Niu and Batiza, 1991] are critically examined. New quantitative methods for mantle melting and high pressure fractionation are developed to evaluate the chemical consequences of melting and fractionation processes and mantle heterogeneity. The new methods rely on new equations for partition coefficients for the major elements between mantle minerals and melts. The melting calculations can be used to investigate the chemical compositions produced by small extents of melting or high pressures of melting that cannot yet be determined experimentally. Application of the new models to the observations described above leads to two major conclusions: (1) The global correlations for normal ridges are caused by variations in mantle temperature, as suggested by Klein and Langmuir [1987] and not by mantle heterogeneity. (2) Local variations are caused by melting processes, but are not yet quantitatively accounted for. On slower spreading ridges, local variations are controlled by the melting regime in the mantle. On the EPR, local variations are predominantly controlled by ubiquitous, small scale heterogeneites. Volatile content may be an important and as yet undetermined factor in affecting the observed variations in major elements. We propose a hypothesis, similar to one proposed by Allegre et al [1984] for isotopic data, to explain the differences between the Atlantic and Pacific local trends, and the trace element systematics of the two ocean basins, as consequences of spreading rate and a different distribution of enriched components from hot spots in the two ocean basins. In the Atlantic, the hot spot influence is in discrete areas, and produces clear depth and chemical anomalies. Ridge segments far from hot spots do not contain enriched

The Escalation of Commitment to a Failing Course of Action: Toward Theoretical Progress

Abstract: Escalating commitment (or escalation) refers to the tendency for decision makers to persist with failing courses of action. The present article first reviews evidence suggesting that escalation is determined, at least in part, by decision makers' unwillingness to admit that their prior allocation of resources to the chosen course of action was in vain (the self-justification explanation). A distinction is drawn in the second part of the article between alternative (to self-justification) explanations of escalating commitment: Some are designed to replace self-justification, whereas others are intended to supplement self-justification, that is, to add explanatory power beyond that which can be accounted for by self-justification. There is little evidence that the replacement theories provide a better explanation than does self-justification; however, theories designed to supplement self-justification are likely to lead to a more complete explanation. The article concludes by describing several research str...

Recombinant tissue plasminogen activator in acute thrombotic and embolic stroke

Abstract: An open angiography-based, dose rate escalation study on the effect of intravenous infusion of recombinant tissue plasminogen activator (rt-PA) on cerebral arterial recanalization in patients with acute focal cerebral ischemia was performed at 16 centers. Arterial occlusions consistent with acute ischemia in the carotid or vertebrobasilar territory in the absence of detectable intracerebral hemorrhage were prerequisites for treatment. After the 60-minute rt-PA infusion, arterial perfusion was assessed by repeat angiography and computed tomography scans were performed at 24 hours to assess hemorrhagic transformation. Of 139 patients with symptoms of focal ischemia, 80.6% (112) had complete occlusion of the primary vessel at a mean of 5.4 +/- 1.7 hours after symptom onset. No dose rate response of cerebral arterial recanalization was observed in 93 patients who completed the rt-PA infusion. Middle cerebral artery division (M2) and branch (M3) occlusions were more likely to undergo recanalization by 60 minutes than were internal carotid artery occlusions. Hemorrhagic infarction occurred in 20.2% and parenchymatous hematoma in 10.6% of patients over all dose rates, while neurological worsening accompanied hemorrhagic transformation (hemorrhagic infarction and parenchymatous hematoma) in 9.6% of patients. All findings were within prospective safety guidelines. No dose rate correlation with hemorrhagic infarction, parenchymatous hematoma, or both was seen. Hemorrhagic transformation occurred significantly more frequently in patients receiving treatment at least 6 hours after symptom onset. No relationship between hemorrhagic transformation and recanalization was observed. This study indicates that site of occlusion, time to recanalization, and time to treatment are important variables in acute stroke intervention with this agent.

The oxidant stress hypothesis in Parkinson's disease: Evidence supporting it

Abstract: Oxidant stress, due to the formation of hydrogen peroxide and oxygen-derived free radicals, can cause cell damage due to chain reactions of membrane lipid peroxidation. Because the substantia nigra is rich in dopamine, which can undergo both enzymatic oxidation via monoamine oxidase and nonenzymatic autoxidation, hydrogen peroxide and oxyradicals (superoxide anion radical and hydroxyl radical) are generated in this midbrain nucleus. Although proof that oxidant stress actually causes the loss of monoaminergic neurons in patients with Parkinson's disease is lacking, there is a considerable body of evidence from studies in both animals and humans that support the concept. (1) Neurotoxins that selectively destroy the dopaminergic neurons in the nigra, such as 6-hydroxydopamine and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), appear to act via oxidant stress. (2) The substantia nigra of patients with Parkinson's disease reveals evidence of oxidant stress by the findings of increased lipid peroxidation and decreased reduced glutathione. (3) Total iron is increased and ferritin is reduced in the substantia nigra pars compacta in patients with Parkinson's disease. This combination suggests that this transition metal is in a low molecular weight form, capable of catalyzing nonenzymatic oxidative reactions, especially the conversion of hydrogen peroxide to hydroxyl radical, which is the most reactive of the oxygen radicals. (4) Neuromelanin, a product of dopamine autoxidation, can serve as a reservoir for iron, promoting the generation of oxyradicals. (5) Antioxidant defense mechanisms appear to be reduced in the parkinsonian substantia nigra with the findings of decreased activities of glutathione peroxidase and catalase.(ABSTRACT TRUNCATED AT 250 WORDS)

Diversification posture and top management team characteristics

Abstract: This study's argument is that a firm's diversification posture determines the degree of integration it needs across business units, which in turn influences the ideal composition of its corporate t...

Structure of a C-type mannose-binding protein complexed with an oligosaccharide.

Abstract: C-type (Ca2+-dependent) animal lectins such as mannose-binding proteins mediate many cell-surface carbohydrate-recognition events. The crystal structure at 1.7 A resolution of the carbohydrate-recognition domain of rat mannose-binding protein complexed with an oligomannose asparaginyl-oligosaccharide reveals that Ca2+ forms coordination bonds with the carbohydrate ligand. Carbohydrate specificity is determined by a network of coordination and hydrogen bonds that stabilizes the ternary complex of protein, Ca2+ and sugar. Two branches of the oligosaccharide crosslink neighbouring carbohydrate-recognition domains in the crystal, enabling multivalent binding to a single oligosaccharide chain to be visualized directly.

Time to recovery, chronicity, and levels of psychopathology in major depression. A 5-year prospective follow-up of 431 subjects

Abstract: • The course of illness of 431 subjects with major depression participating in the National Institute of Mental Health Collaborative Depression Study was prospectively observed for 5 years. Twelve percent of the subjects still had not recovered by 5 years. There were decreasing rates of recovery over time. For example, 50% of the subjects recovered within the first 6 months, and then the rate of recovery declined markedly. Instantaneous probabilities of recovery reflect that the longer a patient was ill, the lower his or her chances were of recovering. For patients still depressed, the likelihood of recovery within the next month declined from 15% during the first 3 months of follow-up to 1 % to 2% per month during years 3, 4, and 5 of this follow-up. The severity of current psychopathology predicted the probability of subsequent recovery. Subjects with moderately severe depressive symptoms, minor depression, or dysthymia had an 18-fold greater likelihood of beginning recovery within the next week than did subjects who were at full criteria for major depressive disorder. Many subjects who did not recover continued in an episode that looked more like dysthymia than major depressive disorder.

Capital Mobility in Neoclassical Models of Growth

Abstract: The empirical evidence reveals conditional convergence in the sense that economies grow faster per capita if they start further below their steady-state positions. For a homogeneous group of economies - like the U.S. states, regions of western European countries, and the GECD countries - the convergence is unconditional in that the poor economies grow faster than the rich ones. The neoclassical growth model for a closed economy fits these facts if capital is viewed broadly to encompass human investments, so that diminishing returns to capital set in slowly, and if differences in government policies or preferences about saving lead to heterogeneity in steady-state positions. Yet if the model is opened to allow for full capital mobility, then the predicted rates of convergence for capital and output are much higher than those observed empirically. We show that the open-economy model conforms with the evidence if an economy can use foreign debt to finance only a portion of its capital, even if 50% or more of the total. The problems in using human capital as collateral can explain the required imperfection in the credit market.

How Well Does The IS-LM Model Fit Postwar U. S. Data?

Abstract: Postwar U. S. time series for money, interest rates, prices, and GNP are characterized by a multivariate process driven by four exogenous disturbances. Those disturbances are identified so that they can be interpreted as the four main sources of fluctuations found in the IS-LM-Phillips curve model: money supply, money demand, IS, and aggregate supply shocks. The dynamic properties of the estimated model are analyzed and shown to match most of the stylized predictions of the model. The estimated decomposition is also used to measure the relative importance of each shock, to interpret some macroeconomic episodes, and to study sources of permanent shocks to nominal variables.

Binge eating disorder: A multisite field trial of the diagnostic criteria

Abstract: Diagnostic criteria have been developed for a new eating disorder, binge eating disorder (BED), to describe the many individuals who have problems with recurrent binge eating but do not engage in the characteristic compensatory behaviors of bulimia nervosa, vomiting, or use of laxatives. The results of a multisite field trial involving 1,984 subjects indicate that the disorder is common (30.1%) among subjects attending hospital-affiliated weight control programs, but is relatively rare in the community (2.0%). The disorder is more common in females than in males and is associated with severity of obesity and a history of marked weight fluctuations. Based on these results, the DSM-IV Work Group on Eating Disorders has recommended that the disorder be considered for inclusion in DSM-IV, either as an official category or in an appendix of categories requiring further study.

Second-Generation Decline: Scenarios for the Economic and Ethnic Futures of the Post-1965 American Immigrants

Abstract: ‘Second-Generation Decline’ questions the current American faith in the myth of nearly automatic immigrant success. In discussing economic scenarios, positive and negative, for the future of the children of the post-1965 immigrants, it proposes the possibility that a significant number of the children of poor immigrants, especially dark-skinned ones, might not obtain jobs in the mainstream economy. Neither will they be willing — or even able — to take low-wage-long-hour ‘immigrant’ jobs like their parents. As a result they, and young males among them particularly, may join blacks and Hispanics among those already excluded, apparently permanently, from the mainstream economy. The paper also deals with the relations between ethnicity and economic conditions in the US, and with the continued relevance of the assimilation and acculturation processes described by ‘straight-line theory’. This issue, as well as most others discussed in the paper, may also be salient for European countries experiencing immigration, especially those countries with troubled economies.

Service utilization and social morbidity associated with depressive symptoms in the community.

Abstract: Objective. —To estimate service utilization and social morbidity in the community associated with depressive symptoms. Estimates were made using an epidemiologic measure, population attributable risk. Population attributable risk is a compound measure reflecting both the morbid risk to an individual with a disorder and the prevalence of the disorder in the community. Design. —Epidemiologic survey. Participants. —Eighteen thousand five hundred seventy-one adults in the Epidemiologic Catchment Area Study interviewed from a complex random sample in five US communities. Outcome Measures. —Suicide attempts, use of psychoactive medications, self-reported physical and emotional health, time lost from work, and general medical services or use of emergency departments for emotional problems. Results. —Major depression-dysthymia (lifetime prevalence, 6.1%) and depressive symptoms (lifetime prevalence, 23.1%) were associated with increased service utilization and social morbidity as measured by the outcome variables. On a population basis, however, as much or more service burden and impairment was associated with depressive symptoms as with the clinical conditions of depression or dysthymia. The equal association results from the greater prevalence of depressive symptoms. Population attributable risk percentages associated with depressive symptoms (not disorder) were as follows: emergency department use (11.8%) or medical consultations for emotional problems (21.5%); use of tranquilizers (14.6%), sleeping pills (21.0%), or antidepressants (22.2%); fair or poor self-reported emotional health (15.3%); days lost from work (17.8%); and suicide attempts (25.0%). Conclusions. —Estimates of population attributable risk indicated that physicians actually provided services to more persons with depressive symptoms than to persons with formally defined conditions of depressive disorders. Subclinical depression, as a consequence of high prevalence, is a clinical and public health problem. Attention to diagnostic and treatment issues is indicated. ( JAMA . 1992;267:1478-1483)