A simple enzymatic assay for the quantification of C1-specific cellulose oxidation by lytic polysaccharide monooxygenases.

OBJECTIVE: The development of an enzymatic assay for the specific quantification of the C1-oxidation product, i.e. gluconic acid of cellulose active lytic polysaccharide monooxygenases (LPMOs). RESULTS: In combination with a ß-glucosidase, the spectrophotometrical assay can reliably quantify the specific C1- oxidation product of LPMOs acting on cellulose. It is applicable for a pure cellulose model substrate as well as lignocellulosic biomass. The enzymatic assay compares well with the quantification performed by HPAEC-PAD. In addition, we show that simple boiling is not sufficient to inactivate LPMOs and we suggest to apply a metal chelator in addition to boiling or to drastically increase pH for proper inactivation. CONCLUSIONS: We conclude that the versatility of this simple enzymatic assay makes it useful in a wide range of experiments in basic and applied LPMO research and without the need for expensive instrumentation, e.g. HPAEC-PAD.

The influence of comorbid disorders on the episodicity of bipolar disorder in youth.

OBJECTIVE: Bipolar disorder (BP) frequently co-occurs with other psychiatric disorders. We examine whether course of anxiety disorders (ANX), attention deficit hyperactivity disorder (ADHD), disruptive behavior disorders (DBD), and substance use disorders (SUD) influence likelihood of recovery and recurrence of depression and mania in BP youth. METHOD: Weekly ratings of psychiatric disorder intensity were obtained from 413 participants of the Course and Outcome of BP Youth project, followed for an average of 7.75 years. Multiple-event Cox proportional hazards regression analyses examined worsening of comorbid disorders as predictors of mood episode recovery and recurrence. RESULTS: Increased severity in ANX and SUD predicted longer time to recovery and less time to next depressive episode, and less time to next manic episode. Multivariate models with ANX and SUD found that significant effects of ANX remained, but SUD only predicted longer time to depression recovery. Increased severity of ADHD and DBD predicted shorter time to recurrence for depressive and manic episodes. CONCLUSION: There are significant time-varying relationships between the course of comorbid disorders and episodicity of depression and mania in BP youth. Worsening of comorbid conditions may present as a precursor to mood episode recurrence or warn of mood episode protraction.

Borderline personality disorder in transition age youth with bipolar disorder.

OBJECTIVE: To determine the longitudinal impact of borderline personality disorder (BPD) on the course and outcome of bipolar disorder (BP) in a pediatric BP sample. METHOD: Participants (N = 271) and parents from the Course and Outcome of Bipolar Youth (COBY) study were administered structured clinical interviews and self-reports on average every 8.7 months over a mean of 93 months starting at age 13.0 ± 3.1 years. The structured interview for DSM-IV personality disorders (SIDP-IV) was administered at the first follow-up after age 18 to assess for symptoms of BPD. BPD operationalized at the disorder, factor, and symptom level, was examined as a predictor of poor clinical course of BP using all years of follow-up data. RESULTS: The number of BPD symptoms was significantly associated with poor clinical course of BP, above and beyond BP characteristics. Affective dysregulation was most strongly associated with poor course at the factor level; the individual symptoms most strongly associated with poor course were dissociation/stress-related paranoid ideation, impulsivity, and affective instability. CONCLUSION: BPD severity adds significantly to the burden of BP illness and is significantly associated with a more chronic and severe course and outcome beyond what can be attributable to BP characteristics.

Dyadic discord at baseline is associated with lack of remission in the acute treatment of chronic depression.

BACKGROUND: Dyadic discord, while common in depression, has not been specifically evaluated as an outcome predictor in chronic major depressive disorder. This study investigated pretreatment dyadic discord as a predictor of non-remission and its relationship to depressive symptom change during acute treatment for chronic depression. METHOD: Out-patients with chronic depression were randomized to 12 weeks of treatment with nefazodone, the Cognitive Behavioral Analysis System of Psychotherapy or their combination. Measures included the Marital Adjustment Scale (MAS) and the Inventory of Depressive Symptomatology - Self Report (IDS-SR30). Of 681 original patients, 316 were partnered and 171 of these completed a baseline and exit MAS, and at least one post-baseline IDS-SR30. MAS scores were analysed as continuous and categorical variables ('dyadic discord' v. 'no dyadic discord' defined as an MAS score >2.36. Remission was defined as an IDS-SR30 of 14 at exit (equivalent to a 17-item Hamilton Rating Scale for Depression of 7). RESULTS: Patients with dyadic discord at baseline had lower remission rates (34.1%) than those without dyadic discord (61.2%) (all three treatment groups) (chi2=12.6, df=1, p=0.0004). MAS scores improved significantly with each of the treatments, although the change was reduced by controlling for improvement in depression. Depression remission at exit was associated with less dyadic discord at exit than non-remission for all three groups [for total sample, 1.8 v. 2.4, t(169)=7.3, p<0.0001]. CONCLUSIONS: Dyadic discord in chronically depressed patients is predictive of a lower likelihood of remission of depression. Couple therapy for those with dyadic discord may increase remission rates.

Recovery in major depressive disorder: analysis with the life table and regression models.

Regression models and life tables were used to describe the phenomenon of recovery from major depressive disorder for 101 patients in a naturalistic study in which treatment was not controlled by the investigators. Time to recovery from the onset of the episode was protracted, as only about 50% of patients recovered by one year. Annual rates of recovery then declined steadily to 28% in the second year, 22% in the third year, and 18% in the fourth year. In contrast, speed of recovery from entry into the study was more rapid, and 63% of patients recovered by four months. The recovery rates were about 20% each month for the first four months and then declined sharply for the remaining months of the one-year follow-up. Several clinical variables were statistically significant predictors of recovery when measured from entry into the study: superimposition of the acute episode on a chronic underlying depression, acuteness of onset of he depression, and severity of depression for the subgroup of patients without superimposed illness.

Relapse in major depressive disorder: analysis with the life table.

With the use of life tables to describe time while patients were well and subsequent rates of relapse for 75 patients after their recovery from an episodes of major depressive disorder in naturalistic study, a high risk of relapse was detected shortly after recovery. Twenty-four percent of patients relapsed within 12 weeks at risk, and 12% of patients relapsed with four weeks at risk. The presence of an underlying chronic depression and three or more previous affective episodes predicted a statistically significant increase in the rate of relapse. These data were used to develop an exponential model of relapse probability for a subgroup of the study population.

Premorbid personality assessments of first onset of major depression.

This is a report on personality traits associated with the first onset of major depression in a sample of high-risk subjects. The subjects are the first-degree relatives, spouses, and their controls of patients with affective disorders. None of these subjects had any history of mental disorder as of their initial evaluation. In the subsequent six years, 29 subjects had a first onset of major depression. These first onset subjects were compared with 370 subjects who continued to be free of illness during the six-year follow-up. Personality traits were assessed at the initial evaluation (ie, before the onset of depression in subjects with first onset) by means of scales from five self-report inventories. Lower emotional strength and resiliency significantly differentiated the first onset from the never ill group; overall differences were not found on measures of interpersonal dependency or extraversion. Age was a significant predictor of first onset, both alone (younger age predicted first onsets) and in interaction with personality measures. Among younger subjects (17 to 30 years of age), personality variables did not significantly discriminate between the two comparison groups. Among older subjects (31 to 41 years of age), however, decreased emotional strength, increased interpersonal dependency, and increased thoughtfulness were associated with first onset of depression.

Reliability studies of psychiatric diagnosis. Theory and practice.

The existing literature on the reliability of psychiatric diagnosis falls into two periods, the earlier reporting low reliability and the latter reporting much higher figures. The reasons for this trend are examined in the context of a discussion of the design of diagnostic reliability studies. The problems of research design and execution in studies of diagnostic reliability are reviewed, and statistical problems are examined. Solutions to many of these problems ae suggested, including recommendations of appropriate reliability coefficients and data analyses.

Situational major depressive disorder.

Fifty-seven patients with situational major depression diagnosed by the Research Diagnostic Criteria were compared with 72 subjects with nonsituational major depression on demographic, clinical, and psychosocial variables. The situational patients tended to be younger and had fewer prior episodes of depression and fewer hospitalizations. No differences were found in categories of life events, in overall clinical picture, in social supports, or in family history.

Impact of severity and chronicity of parental affective illness on adaptive functioning and psychopathology in children.

We report on the impact of specific indexes of the severity and chronicity of parental depression, measures of familial discord, and demographic variables as predictors of impaired adaptive functioning and psychopathology in children. Seventy-two children and their mothers from 37 families were interviewed in person. At least one biological parent in each family had a depressive disorder but neither parent had a history of mania, schizophrenia, or schizoaffective disorder. Almost every measure of severity and chronicity of depression in the biological parents has a statistically significant association with currently impaired adaptation and the presence of a DSM-III-diagnosed disorder in the children, as do the measures of increased discord among married or separated parents. Depression in the mother is more strongly associated with increased psychopathology in the children than is depression in the father.

The validation of the concept of endogenous depression. A family study approach.

Depressive illnesses are subdivided into endogenous and nonendogenous types in psychiatry throughout the world. We used one method of validating this nosologic subdivision: the determination of the extent to which the disorder is familial. Rates of depression were examined in 2,942 first-degree relatives of 566 individuals diagnosed as having unipolar major depressive disorder. Because no single definition of endogenous depression is universally accepted, four different methods for defining endogenous depression were compared: the Newcastle Scale, the Research Diagnostic Criteria, DSM-III, and the definition of "autonomous depression" proposed by investigators at Yale University (New Haven, Conn). In general, no matter which definition was used, the relatives of the patients with endogenous illness did not have higher rates of depressive illness than those of the nonendogenous group. The Newcastle Scale was the most sensitive in picking up familial transmission of recurrent unipolar depression. The results of this investigation suggest that longitudinal approaches should be added to cross-sectional approaches for the best definition of endogenous depression.

Personality and depression. Empirical findings.

The Clinical Studies of the National Institute of Mental Health--Clinical Research Branch Collaborative Program on the Psychobiology of Depression offer an opportunity to clarify the relationship between personality and depression. Thirty-one female patients with primary nonbipolar major depressive disorder were assessed diagnostically using the Schedule for Affective Disorders and Schizophrenia and completed a battery of standard self-report personality inventories when they were completely symptom free. Their personality scale scores were compared with those of female relatives who had recovered from the same type of disorder, those of female relatives with no history of psychiatric illness, and published scale norms. Compared with the normal population, both groups of recovered depressives were introverted, submissive, and passive, with increased interpersonal dependency but normal emotional strength. Comparison to never-ill relatives yielded similar results except that the never-ill relatives had scores reflecting extraordinary emotional strength.

Reliability of lifetime diagnosis. A multicenter collaborative perspective.

It is important to determine the reliability of lifetime diagnosis in a nonpatient population, for this type of diagnostic data and this type of sample are used in many genetic, epidemiological, and nosological studies. We examined the reliability of lifetime diagnosis when the Schedule for Affective Disorders and Schizophrenia-Lifetime Version and Research Diagnostic Criteria were used to interview ill and well relatives of probands in the National Institute of Mental Health Collaborative Study of the Psychobiology of Depression. Subjects were interviewed three times, so data are available concerning both short- and long-interval test-retest reliability. Short-interval test-retest reliability was excellent for both diagnoses and symptoms. Reliability was also quite high in the long-interval test-retest study. We conclude that it is possible to make lifetime diagnoses reliably in a nonpatient population.

Low levels and lack of predictors of somatotherapy and psychotherapy received by depressed patients.

We examined the treatment of 338 patients with nonbipolar major depressive disorders during the first eight weeks after entry into the National Institute of Mental Health-Clinical Research Branch Collaborative Program on the Psychobiology of Depression: Clinical Study. Of the 250 entered as inpatients, 31% received either no antidepressant somatotherapy or very low or unsustained levels, and only 49% received at least 200 mg of imipramine hydrochloride (or its equivalent) for four consecutive weeks. Of these patients, 19% received less than 30 minutes of psychotherapy per week. Among the 88 who entered as outpatients, 29% received no antidepressant somatotherapy; another 24% received very low or unsustained levels; only 19% received at least 200 mg of imipramine hydrochloride or its equivalent for four consecutive weeks. Of these patients, 52% received less than 30 minutes of psychotherapy per week. Only a few clinical factors were found to be predictive of treatment intensity. Very large differences in the amount and type of treatment across the five collaborating university centers do not appear to be related to differences in patient characteristics.

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

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.

The Longitudinal Interval Follow-up Evaluation. A comprehensive method for assessing outcome in prospective longitudinal studies.

The Longitudinal Interval Follow-up Evaluation (LIFE) is an integrated system for assessing the longitudinal course of psychiatric disorders. It consists of a semistructured interview, an Instruction booklet, a coding sheet, and a set of training materials. An interviewer uses the LIFE to collect detailed psychosocial, psychopathologic, and treatment information for a six-month follow-up interval. The weekly psychopathology measures ("psychiatric status ratings") are ordinal symptom-based scales with categories defined to match the levels of symptoms used in the Research Diagnostic Criteria. The ratings provide a separate, concurrent record of the course of each disorder initially diagnosed in patients or developing during the follow-up. Any DSM-III or Research Diagnostic Criteria disorder can be rated with the LIFE, and any length or number of follow-up intervals can be accommodated. The psychosocial and treatment information is recorded so that these data can be linked temporally to the psychiatric status ratings.

Birth-cohort trends in rates of major depressive disorder among relatives of patients with affective disorder.

As part of the National Institute of Mental Health-Clinical Research Branch Collaborative Program on the Psychobiology of Depression Clinical Study, 2,289 relatives of 523 probands with affective disorder were interviewed with the Schedule for Affective Disorders and Schizophrenia and diagnosed for major depressive disorder by the Research Diagnostic Criteria. Data were analyzed using life-table and survival methods. The findings suggest a progressive increase in rates of depression in successive birth cohorts through the 20th century and an earlier age at onset of depression in each birth cohort. A predominance of female depressives was found in all birth cohorts but the magnitude of female-male differences fluctuated over the decades. The existence of these trends is reported to stimulate further research. These findings are discussed in terms of possible gene-environment interactions. However, no conclusive causal inferences can be drawn pending further investigation.

Conceptualization and rationale for consensus definitions of terms in major depressive disorder. Remission, recovery, relapse, and recurrence.

In 1988, the MacArthur Foundation Research Network on the Psychobiology of Depression convened a task force to examine the ways in which change points in the course of depressive illness had been described and the extent to which inconsistency in these descriptions might be impeding research on this disorder. We found considerable inconsistency across and even within research reports and concluded that research on depressive illness would be well served by greater consistency in the definition change points in the course of illness. We propose an internally consistent, empirically defined conceptual scheme for the terms remission, recovery, relapse, and recurrence. In addition, we propose tentative operational criteria for each term. Finally, we discuss ways to assess the usefulness of such operational criteria through reanalysis of existing data and the design and conduct of new experiments.

Subsyndromal symptoms in bipolar disorder. A comparison of standard and low serum levels of lithium.

Ninety-four patients with bipolar disorder participating in a random-assignment, double-blind, prospective maintenance trial of standard- (0.8 to 1.0 mmol/L) vs low-range (0.4 to 0.6 mmol/L) serum lithium levels were assessed to determine the presence and significance of subsyndromal symptoms during periods of remission and recovery. A significant relationship was found between prescribed serum lithium level and the probability of major affective relapse and the occurrence of subsyndromal symptoms. Patients given lithium carbonate to achieve low-range levels had 2.6 times the risk of major affective relapse as those given lithium for standard-range levels and nearly twice the risk of developing subsyndromal symptoms. Patients given the low-range therapy showed a greater variance in weekly Psychiatric Status Rating measures, and their symptoms were more likely to worsen at any time than were symptoms in their standard-level group counterparts. The first occurrence of subsyndromal symptoms increased the risk of major affective relapse fourfold. Following the onset of subsyndromal symptoms, the patients originally randomized to receive standard-range lithium therapy were still better protected from relapse than were patients randomized to receive low-range lithium treatment. Patients were two times more likely to develop depressive than hypomanic symptoms between acute episodes of illness. However, onset of hypomanic symptoms predicted subsequent major affective relapse twice as strongly as did depressive symptoms. Seventy-six percent of patients who became hypomanic had a major affective relapse, compared with 39% of patients who were subclinically depressed.

The time course of nonchronic major depressive disorder. Uniformity across episodes and samples. National Institute of Mental Health Collaborative Program on the Psychobiology of Depression--Clinical Studies.

BACKGROUND: Most natural history studies of affective disorders have emphasized the prediction of eventual recovery. Little is known of changes over time in the immediate probability of recovery. METHODS: To identify regularities in the timing of recovery from nonbipolar major depressive disorders, we considered only episodes that began during follow-up to increase the accuracy with which onsets were timed and to limit the study sample to individuals who had a demonstrably episodic course. Five participating centers conducted baseline assessments and followed probands (N = 605) and nonclinical subjects (relatives, controls, and spouses, N = 826) up for 6 years. During that time, 359 probands had at least one prospectively observed episode, and 181 had two episodes; corresponding numbers for the nonclinical subjects were 216 and 78, respectively. Our analyses considered the distribution of episode lengths across ascertainment source (probands vs nonclinical subjects), center, and episode number (first vs second prospectively observed episode). RESULTS: Distribution was remarkably uniform. Regardless of ascertainment source, center, or episode number, recovery occurred within 3 months in 40% of episodes, within 6 months in 60%, and within 1 year in 80%; 20% had more protracted courses. CONCLUSIONS: Once triggered, the immediate likelihood of recovery changes over time in a predictable fashion. This has practical implications for the study of antidepressant efficacy and theoretical implications for factors involved in affective dysregulation.