Macroclimate associated with urbanization increases the rate of secondary succession from fallow soil.

To examine the impact of projected climate changes on secondary succession, we exposed the same fallow soil with a common seed bank to an in situ gradient of urban to rural macroenvironments that differed in temperature and CO2 concentration ([CO2]). This gradient was established at three locations: Baltimore city center (urban), a city park on the outskirts of Baltimore (suburban), and an organic farm 87 km from the Baltimore city center site (rural). Over a five-year period, the urban site averaged 2.1 degrees C warmer and had a [CO2] that was ~20% higher than at the rural location, indicating that this gradient was a reasonable surrogate for projected changes in those variables for this century. Previous work had demonstrated that other abiotic variables measured across the transect, including tropospheric ozone and nitrogen deposition, did not differ consistently. The first year of exposure resulted in (two- to threefold) greater aboveground biomass in the urban relative to the rural site, but with uniform species composition across sites. Simple regression of abiotic variables indicated that temperature and vapor pressure deficit (VPD) were the best predictors of plant biomass among locations. Stepwise multiple regressions were also performed to analyze the effect of more than one macroenvironmental variable on total plant biomass. The combination of daily CO2 concentration and nighttime temperature explained 87% (P < 0.01) of the variability in total biomass between sites. After five years, the species demography of the plant communities had changed significantly, with a greater ratio of perennials to annuals for the urban relative to the rural location. Greater first-year biomass and litter accumulation at the urban site may have suppressed the subsequent seed germination of annual species, accelerating changes in species composition. If urban macroenvironments reflect future global change conditions, these data suggest a faster rate of secondary succession in a warmer, higher [CO2] world.

Self-devaluative dysphoric experience and the prediction of persistent first-episode major depressive disorder in adolescents.

BACKGROUND: The quality of subjective experience of dysphoria may predict persistence of depression, independently of severity. This is tested in a clinic sample of adolescents with first episode of major depression using the Depressed States Checklist adapted for adolescents. METHOD: Ninety-four adolescents with DSM-IV major depressive disorder (MDD) were followed up at 12 months. Self-devaluative components of dysphoric experience, ruminative style, over-general autobiographical memory, and self-reported and observer-rated measures of depression severity were assessed at presentation and evaluated as predictors of persistent MDD. RESULTS: Persistent MDD was predicted by the independent additive effects of the higher self-devaluative component of dysphoria, lower general intelligence and greater observer-rated severity of depression at presentation. Neither self-reported depression score, overgeneral memory retrieval nor ruminative style contributed. CONCLUSIONS: High levels of self-devaluative dysphoric experience increase the liability for persistence of first-episode MDD. Other affective-cognitive components also contribute. The adolescent version of the Depressed States Checklist is a useful brief measure of cognitive vulnerability for persistence in currently depressed young people.

Effects of induced rumination and distraction on mood and overgeneral autobiographical memory in adolescent Major Depressive Disorder and controls.

BACKGROUND: In adults there is evidence that the affective-cognitive processes of rumination and overgeneral autobiographical memory retrieval may play a part in maintaining depression. This study investigated the effects of induced rumination as compared to distraction on mood and categoric overgeneral memory in adolescents with first episode Major Depressive Disorder (MDD), and the specificity of any effects to MDD. METHOD: Three subject groups; adolescents with first episode MDD (N = 75), non-depressed psychiatric participants (N = 26) and community controls (N = 33) were recruited. An experimental design was used, with repeated measures of 'in the moment' depressed mood and categoric overgeneral memory before and after rumination and distraction, induced on separate occasions and counterbalanced in order across participants. RESULTS: In adolescents with MDD, induced rumination as compared to distraction differentially increased depressed mood. There were no significant differences in this effect between full current MDD participants and those in partial remission. This differential effect was also seen in community controls but was absent in non-MDD psychiatric participants. In addition, rumination as compared to distraction increased overgeneral memories to negative cues in MDD participants, but this increase was not significantly related to mood change, and was specific to MDD, being absent in non-MDD psychiatric and community control groups. CONCLUSIONS: Experimentally induced rumination as compared to distraction increases depressed mood and negative categoric memories in adolescents with first episode MDD. These results suggest that rumination has a deleterious effect on mood and memory retrieval processes in adolescents with first episode MDD. Increased negative overgeneral memories with rumination may be a process of particular importance for adolescents with MDD rather than psychiatric disorder in general. The findings imply that strategies to interrupt ruminative processes may be helpful in minimising persistence of first episode MDD in adolescence.

Categoric overgeneral autobiographical memory in adolescents with major depressive disorder.

BACKGROUND: Categoric, overgeneral autobiographical memory is more common in depressed adults than controls and predicts persistence of depression. This cross-sectional study investigated whether, compared with non-depressed psychiatric cases and community controls, first episode major depressive disorder (MDD) in adolescents is associated with categoric overgeneral memory retrieval. METHODS: Ninety-six clinically referred adolescents (aged 12-17 years) with MDD, 26 non-depressed psychiatric cases and a sample of 33 community controls were recruited. All subjects were assessed using the Kiddie-Schedule for Schizophrenia and Affective Disorders, and completed Williams' cued Autobiographical Memory Test and the Mood and Feelings Questionnaire. Hamilton Depression Rating Scales were completed with MDD subjects, as an index of depression severity. RESULTS: Adolescents with current first episode MDD retrieved more categoric overgeneral memories than controls, but not than non-depressed psychiatric cases. Adolescents in full remission from a recent episode of MDD retrieved more categoric memories to positive cues than controls. Categoric memory in MDD was related to observer-rated and self-reported severity, but not to the pattern of co-morbid diagnoses. There were negative correlations between IQ and categoric memories in both clinical cases and controls. A positive correlation between categoric memory to negative cues and self-reported depressive symptoms was found in clinical cases (but not controls). CONCLUSIONS: In adolescents, increased categoric overgeneral memory is associated with, but not specific to first episode MDD. Positive categoric memories are also increased in fully remitted MDD as compared to controls.

Runoff loss of pesticides and soil: a comparison between vegetative mulch and plastic mulch in vegetable production systems.

Current vegetable production systems use polyethylene (plastic) mulch and require multiple applications of agrochemicals. During rain events, runoff from vegetable production is enhanced because 50 to 75% of the field is covered with an impervious surface. This study was conducted to quantify off-site movement of soil and pesticides with runoff from tomato (Lycopersicon esculentum Mill.) plots containing polyethylene mulch and a vegetative mulch, hairy vetch (Vicia villosa Roth). Side-by-side field plots were instrumented with automated flow meters and samplers to measure and collect runoff, which was filtered, extracted, and analyzed to determine soil and pesticide loss. Seasonal losses of two to four times more water and at least three times as much sediment were observed from plots with polyethvlene mulch (55.4 to 146 L m(-2) and 247 to 535 g m(-2), respectively) versus plots with hairy vetch residue (13.7 to 75.7 L m(-2) and 32.8 to 118 g m(-2), respectively). Geometric means (+/-standard deviation) of total pesticide loads for chlorothalonil (tetrachloroisophthalonitrile) and alpha-and beta-endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro6,9-methano-2,4,3-benzodioxathiepin 3-oxide) for a runoff event were 19, 6, and 9 times greater from polyethylene (800+/-4.6, 17.6+/-3.9, and 39.1+/-4.9 microg m(-2), respectively) than from hairy vetch mulch plots (42+/-6.0, 2.8+/-5.0, and 4.3+/-4.6 microg m(-2), respectively) due to greater concentrations and larger runoff volumes. The increased runoff volume, soil loss, and off-site loading of pesticides measured in runoff from the polyethylene mulch suggests that this management practice is less sustainable and may have a harmful effect on the environment.

Dysphoria: self-devaluative and affective components in recovered depressed patients and never depressed controls.

BACKGROUND: The Interacting Cognitive Subsystems analysis of cognitive vulnerability to depression predicts that subjective experiences of dysphoria in recovered depressed patients will be qualitatively different from those of controls. This study tested this prediction using a new instrument, the Depressed States Checklist. METHODS: Twenty-three recovered recurrently depressed patients and 54 never depressed controls rated the affective and self-devaluative components of a dysphoric experience. RESULTS: Groups reported similar levels of affective component but recovered depressed patients reported higher self-devaluative dysphoric experience. At zero affective component of dysphoria neither group reported any self-devaluative feelings. With increasing affective component of dysphoria, the self-devaluative component increased significantly more in recovered patients than in controls. The ratio of self-devaluative to affective components of dysphoria significantly differentiated recovered depressed patients from controls. CONCLUSIONS: As predicted, dysphoria in recovered depressed patients is qualitatively different from controls in ways that increase vulnerability to major depression. The Depressed States Checklist is a new, brief, measure of cognitive vulnerability to depression that may be particularly useful in large, prospective, epidemiological studies.

How does cognitive therapy prevent relapse in residual depression? Evidence from a controlled trial.

This study examined the cognitive mediation of relapse prevention by cognitive therapy (CT) in a trial of 158 patients with residual depression. Scores based on agreement with item content of 5 questionnaires of depression-related cognition provided no evidence for cognitive mediation. A measure of the form of response to those questionnaires, the number of times patients used extreme response categories ("totally agree" and "totally disagree"), showed significant and substantial prediction of relapse, differential response to CT. and conformity to mediational criteria. CT reduced relapse through reductions in absolutist, dichotomous thinking style. CT may prevent relapse by training patients to change the way that they process depression-related material rather than by changing belief in depressive thought content.

Rumination and overgeneral memory in depression: effects of self-focus and analytic thinking.

Previous research has shown that, compared with a rumination induction, a brief distraction procedure reduces overgeneral autobiographical memory in depression. The authors investigated whether this effect depends on reductions in analytic thinking or reductions in self-focus. Focus of attention (high vs. low self-focus) and thinking style (high vs. low analytical thinking) were independently manipulated in depressed patients in a 2 x 2 design. Autobiographical recall was measured pre- and postmanipulation. Thinking style significantly affected overgeneral memory, whereas focus of attention significantly affected despondent mood. Reducing analytical self-focus reduced overgeneral memory, suggesting that high levels of naturally occurring ruminative analytic thinking may be important in the maintenance of overgeneral memory. Overgeneral memory in depression may be associated with chronic ruminative attempts to make sense of current or past difficulties.

Effects of cognitive therapy on psychological symptoms and social functioning in residual depression.

BACKGROUND: About 30% of psychiatric out-patients with major depression demonstrate partial remission. AIMS: To explore whether the addition of cognitive therapy (CT) had any differential effect on residual symptoms or social adjustment. METHOD: Patients with residual symptoms of major depression (n=158) were randomised to receive clinical management (CM) alone, or CM plus 18 sessions of CT. Subjects' depressive symptoms and social functioning were assessed regularly over 16 months. RESULTS: The addition of CT produced statistically significant differential effects on: two out of four measures of overall severity of depression; specific psychological symptoms (guilt, self-esteem and hopelessness); and social functioning (including dependency, interpersonal behaviour and friction). CONCLUSIONS: In patients showing only partial response to antidepressants, the addition of CT produced modest improvements in social and psychological functioning. The implications for research on the mechanisms of action of CT are discussed.

Decentring and distraction reduce overgeneral autobiographical memory in depression.

BACKGROUND: Increased recall of categorical autobiographical memories is a phenomenon unique to depression and post-traumatic stress disorder, and is associated with a poor prognosis for depression. Although the elevated recall of categorical memories does not change on remission from depression, recent findings suggest that overgeneral memory may be reduced by cognitive interventions and maintained by rumination. This study tested whether cognitive manipulations could influence the recall of categorical memories in dysphoric participants. METHODS: Forty-eight dysphoric and depressed participants were randomly allocated to rumination or distraction conditions. Before and after the manipulation, participants completed the Autobiographical Memory Test, a standard measure of overgeneral memory. Participants were then randomized to either a 'decentring' question (Socratic questions designed to facilitate viewing moods within a wider perspective) or a control question condition, before completing the Autobiographical Memory Test again. RESULTS: Distraction produced significantly greater decreases in the proportion of memories retrieved that were categorical than rumination. Decentring questions produced significantly greater decreases in the proportion of memories retrieved that were categorical than control questions, with this effect independent of the prior manipulation. CONCLUSIONS: Elevated categorical memory in depression is more modifiable than has been previously assumed; it may reflect the dynamic maintenance of a cognitive style that can be interrupted by brief cognitive interventions.

Prevention of relapse/recurrence in major depression by mindfulness-based cognitive therapy.

This study evaluated mindfulness-based cognitive therapy (MBCT), a group intervention designed to train recovered recurrently depressed patients to disengage from dysphoria-activated depressogenic thinking that may mediate relapse/recurrence. Recovered recurrently depressed patients (n = 145) were randomized to continue with treatment as usual or, in addition, to receive MBCT. Relapse/recurrence to major depression was assessed over a 60-week study period. For patients with 3 or more previous episodes of depression (77% of the sample), MBCT significantly reduced risk of relapse/recurrence. For patients with only 2 previous episodes, MBCT did not reduce relapse/recurrence. MBCT offers a promising cost-efficient psychological approach to preventing relapse/recurrence in recovered recurrently depressed patients.

Mindfulness-based cognitive therapy reduces overgeneral autobiographical memory in formerly depressed patients.

Previous research on depressed and suicidal patients and those with posttraumatic stress disorder has shown that patients' memory for the past is overgeneral (i.e., patients retrieve generic summaries of past events rather than specific events). This study investigated whether autobiographical memory could be affected by psychological treatment. Recovered depressed patients were randomly allocated to receive either treatment as usual or treatment designed to reduce risk of relapse. Whereas control patients showed no change in specificity of memories recalled in response to cue words, the treatment group showed a significantly reduced number of generic memories. Although such a memory deficit may arise from long-standing tendencies to encode and retrieve events generically, such a style is open to modification.

Dysfunctional thinking in major depressive disorder: a deficit in metacognitive monitoring?

Speed of response to attitudinal statements has predictive behavioral significance and reflects the relative contributions of "automatic" access to precomputed schematic representations and slower "controlled" on-line processing. Latencies to Dysfunctional Attitude Scale (A. N. Weissman & A. T. Beck, 1978) and neutral statements were measured in 30 depressed patients and 30 nondepressed controls. For controls, responses incompatible with functional schemas were markedly slowed. This pattern of latencies is consistent with the operation of metacognitive monitoring of potential dysfunctional responses, dependent on limited controlled processing resources. For patients, there was no evidence of selective slowing for these or any other form of response. Results suggest that depressed patients have a deficit of metacognitive monitoring of dysfunctional cognitive products.

Latent negative self-schema and high emotionality in well adolescents at risk for psychopathology.

Teasdale's (1988) differential activation hypothesis proposes that a tendency for negative mood to activate latent negative self-schemas characterises people at risk for depression. The current study tested predictions from this hypothesis in a community sample of 102 adolescents who were free from history of psychiatric illness, and who were subdivided according to level of emotionality, a temperamental style as assessed by parental questionnaire. A musical mood induction task was used to induce temporary mild dysphoria, and the effect of mood induction on self-schemas was assessed. There was no difference between high and low emotionality groups in the liability to sad mood induction. However, adolescents with high emotionality endorsed significantly more negative self-descriptors after dysphoric, but not after neutral, mood induction. This was not accounted for by level of self-reported depressive symptoms over the previous week. This suggests that a " dysphoric mood induction challenge" may provide important information about vulnerability to depression that is not identified by routine self-report of mood or cognitions.

Emotional processing, three modes of mind and the prevention of relapse in depression.

Rachman's (1980) analysis [Rachman, S. (1980). Emotional processing. Behaviour Research and Therapy, 18, 51-60] of emotional processing is extended and applied to the prevention of relapse and recurrence in depression. It is proposed that effective emotional processing leads to changes in the ability of triggering cues to reactivate depressogenic processing cycles at times of potential relapse. Available evidence supports the usefulness of the probe methodology of the emotional processing framework as a way to investigate processes mediating relapse prevention by cognitive therapy. It is proposed that effective emotional processing involves creation of modified affect-related schematic mental models and that this occurs most effectively only within certain processing configurations or modes of mind. Within the Interacting Cognitive Subsystems (ICS) framework, three modes of processing emotional material can be distinguished: 'mindless emoting'; 'conceptualising/doing' and 'mindful experiencing/being'. Only the last of these facilitates emotional processing; the second may prevent effective emotional processing and perpetuate depression by ruminative, conceptually dominated processing. This analysis suggests a further strategy to prevent relapse, in addition to modifying depressogenic schematic models, by teaching recovered depressed patients skills to switch processing modes by intentional redeployment of attention. Results of a recent trial of mindfulness-based cognitive therapy support the effectiveness of this novel alternative strategy.

Anorexia nervosa: friend or foe?

OBJECTIVE: The aim of this study was to examine anorexics' attitudes towards anorexia nervosa. METHOD: Anorexic patients were asked to write two letters to their anorexia nervosa, one addressing it as a friend and the other addressing it as an enemy. A coding scheme was developed using a "Grounded Theory" methodology to group recurrent themes. The scheme was used independently by three raters: the first author, a rater with extensive experience in eating disorders, and a novice in the field. Use of the coding scheme showed high interrater reliability and comprehensivess. RESULTS: Commonly expressed benefits of anorexia nervosa included feeling looked after or protected, gaining a sense of control, and feeling special. Perceived costs of the disorder included constant thoughts about food, feeling taken over, and the damage done to personal relationships. DISCUSSION: The positive themes found in the letters are important indicators of factors which may maintain anorexia nervosa. The use of the letters to examine these factors has important clinical implications which are outlined.

Functional MRI study of the cognitive generation of affect.

OBJECTIVE: The authors investigated, by whole brain functional magnetic resonance imaging (MRI), the neural substrate underlying processing of emotion-related meanings. METHOD: Six healthy subjects underwent functional MRI while viewing 1) alternating blocks of pairs of pictures and captions evoking negative feelings and the same materials irrelevantly paired to produce less emotion (reference pairs); 2) alternating blocks of picture-caption pairs evoking positive feelings and the same materials irrelevantly paired to produce less emotion; and 3) alternating blocks of picture-caption pairs evoking positive feelings and picture-caption pairs evoking negative feelings. RESULTS: Compared with the reference picture-caption pairs, negative pairs activated the right medial and middle frontal gyri, right anterior cingulate gyrus, and right thalamus. Compared with the reference picture-caption pairs, positive pairs activated the right and left insula, right inferior frontal gyrus, left splenium, and left precuneus. Compared with the negative picture-caption pairs, positive pairs activated the right and left medial frontal gyri, right anterior cingulate gyrus, right precentral gyrus, and left caudate. CONCLUSIONS: Contrasts of both 1) negative and reference picture-caption pairs and 2) positive and negative picture-caption pairs activated networks involving similar areas in the medial frontal gyrus (Brodmann's area 9) and right anterior cingu-late gyrus (areas 24 and 32). The area 9 sites activated are strikingly similar to sites activated in related positron emission tomography experiments. Activation of these same sites by a range of evoked affects, elicited by different methods, is consistent with areas within the medial prefrontal cortex mediating the processing of affect-related meanings, a process common to many forms of emotion production.

Prevention of relapse in residual depression by cognitive therapy: a controlled trial.

BACKGROUND: Previous studies indicate that depressed patients with partial remission and residual symptoms following antidepressant treatment are common and have high rates of relapse. There is evidence that cognitive therapy may reduce relapse rates in depression. METHODS: One hundred fifty-eight patients with recent major depression, partially remitted with antidepressant treatment (mean daily doses equivalent to 185 mg of amitriptyline or 33 mg of fluoxetine) but with residual symptoms of 2 to 18 months' duration, were included in a controlled trial. Subjects were randomized to receive clinical management alone or clinical management plus cognitive therapy for 16 sessions during 20 weeks, with 2 subsequent booster sessions. Subjects were assessed regularly throughout the 20 weeks' treatment and for a further year. They received continuation and maintenance antidepressants at the same dose throughout. RESULTS: Cognitive therapy reduced relapse rates for acute major depression and persistent severe residual symptoms, in both intention to treat and treated per protocol samples. The cumulative relapse rate at 68 weeks was reduced significantly, from 47% in the clinical management control group to 29% with cognitive therapy (hazard ratio 0.54; 95% confidence interval, 0.32-0.93; intention to treat analysis). Cognitive therapy also increased full remission rates at 20 weeks but did not significantly improve symptom ratings. CONCLUSION: In this difficult-to-treat group of patients with residual depression who showed only partial response despite antidepressant treatment, cognitive therapy produced worthwhile benefit.

Depressive thinking and dysfunctional schematic mental models.

OBJECTIVES: To examine the replicability and generalizability of findings suggesting that mood-dependent negative thinking in depression reflects changes in the schematic mental models through which the world is interpreted, rather than a generalized increase in accessibility of negative constructs. DESIGN: Depressed and non-depressed samples were compared on a sentence completion task concerning anticipated outcomes of social approval or success. This task was designed so that the schematic mental models view predicted more positive completions from depressed participants, the construct accessibility view predicting the opposite. METHODS: A total of 98 depressed participants (scoring > 15 on the Center for Epidemiologic Studies Depression Scale; CESD) from a depressive self-help organization, and 50 non-depressed controls (CESD < 16) completed the CESD, Sentence Completion Task and the Dysfunctional Attitude Scale (DAS). RESULTS: Depressed participants made more positive completions in the Sentence Completion Task, and scored higher on the DAS than controls. Subanalyses suggested that the depressed group's increased positive completions were accounted for largely by those currently in psychiatric treatment; these participants also showed greater evidence of dysfunctional schematic models on DAS. CONCLUSIONS: For depressed participants in psychiatric treatment, results replicate previous findings, supporting the view that negative depressive thinking reflects a change in schematic mental models through which the world is interpreted. Results are inconsistent with predictions from the construct accessibility view. The results have methodological implications for the use of the sentence completion task in future studies.