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1.
Psychol Med ; 44(14): 3007-16, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25066792

RESUMEN

BACKGROUND: This research assesses whether multi-year treatment with antipsychotic medications reduces or eliminates psychosis in schizophrenia. It provides 20 years of longitudinal data on the frequency and severity of psychotic activity in samples of schizophrenia patients (SZ) treated versus those not treated with antipsychotic medications. METHOD: A total of 139 early young schizophrenia and mood-disordered patients were assessed at index hospitalization and then reassessed six times over 20 years for psychosis and other major variables. RESULTS: At each follow-up assessment over the 20 years, a surprisingly high percentage of SZ treated with antipsychotics longitudinally had psychotic activity. More than 70% of SZ continuously prescribed antipsychotics experienced psychotic activity at four or more of six follow-up assessments over 20 years. Longitudinally, SZ not prescribed antipsychotics showed significantly less psychotic activity than those prescribed antipsychotics (p < 0.05). CONCLUSIONS: The 20-year data indicate that, longitudinally, after the first few years, antipsychotic medications do not eliminate or reduce the frequency of psychosis in schizophrenia, or reduce the severity of post-acute psychosis, although it is difficult to reach unambiguous conclusions about the efficacy of treatment in purely naturalistic or observational research. Longitudinally, on the basis of their psychotic activity and the disruption of functioning, the condition of the majority of SZ prescribed antipsychotics for multiple years would raise questions as to how many of them are truly in remission.


Asunto(s)
Antipsicóticos/farmacología , Trastornos del Humor/tratamiento farmacológico , Evaluación de Resultado en la Atención de Salud , Trastornos Psicóticos/tratamiento farmacológico , Esquizofrenia/tratamiento farmacológico , Adulto , Estudios de Seguimiento , Humanos , Factores de Tiempo
2.
Psychol Med ; 43(6): 1151-60, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23034091

RESUMEN

BACKGROUND: Hallucinations are a major aspect of psychosis and a diagnostic feature of both psychotic and mood disorders. However, the field lacks information regarding the long-term course of hallucinations in these disorders. Our goals were to determine the percentage of patients with hallucinations and the relationship between hallucinations and recovery, and work attainment. Method The present study was a prospective evaluation of the 20-year trajectory of hallucinations in 150 young patients: 51 schizophrenia, 25 schizoaffective, 25 bipolar with psychosis, and 49 unipolar depression. The patients were studied at an index phase of hospitalization for hallucinations, and then reassessed longitudinally at six subsequent follow-ups over 20 years. RESULTS: The longitudinal course of hallucinations clearly differentiated between schizophrenia and bipolar disorder with psychosis, and suggested some diagnostic similarities between schizophrenia and schizoaffective disorder, and between bipolar disorder and schizoaffective disorder and depression. Frequent or persistent hallucinatory activity over the 20-year period was a feature of 40-45% of schizophrenia patients. The early presence of hallucinations predicted the lack of future periods of recovery in all patients. Increased hallucinatory activity was associated with reduced work attainment in all patients. CONCLUSIONS: This study provides data on the prospective longitudinal course of hallucinations, which were previously unavailable to the field, and are one of the key features of psychosis in major psychiatric disorders. This information on the clinical course of major psychiatric disorders can inform accurate classification and diagnosis.


Asunto(s)
Trastorno Bipolar/psicología , Trastorno Depresivo/psicología , Alucinaciones/psicología , Trastornos Psicóticos/psicología , Esquizofrenia/complicaciones , Psicología del Esquizofrénico , Adolescente , Adulto , Progresión de la Enfermedad , Femenino , Humanos , Estudios Longitudinales , Masculino , Estudios Prospectivos , Adulto Joven
3.
Psychol Med ; 42(10): 2145-55, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22340278

RESUMEN

BACKGROUND: The prevailing standard of care in the field involves background assumptions about the importance of prolonged use of antipsychotic medications for all schizophrenia (SZ) patients. However, do all SZ patients need antipsychotics indefinitely? Are there factors that help to identify which SZ patients can enter into prolonged periods of recovery without antipsychotics? This 20-year longitudinal research studied these issues. METHOD: A total of 139 early young psychotic patients from the Chicago Follow-up Study, including 70 patients with SZ syndromes and 69 with mood disorders, were assessed, prospectively, at the acute phase and then followed up six times over the next 20 years. Patients were assessed with standardized instruments for major symptoms, psychosocial functioning, personality, attitudinal variables, neurocognition and treatment. RESULTS: At each follow-up, 30-40% of SZ patients were no longer on antipsychotics. Starting at the 4.5-year follow-ups and continuing thereafter, SZ patients not on antipsychotics for prolonged periods were significantly less likely to be psychotic and experienced more periods of recovery; they also had more favorable risk and protective factors. SZ patients off antipsychotics for prolonged periods did not relapse more frequently. CONCLUSIONS: The data indicate that not all SZ patients need treatment with antipsychotics continuously throughout their lives. SZ patients not on antipsychotics for prolonged periods are a self-selected group with better internal resources associated with greater resiliency. They have better prognostic factors, better pre-morbid developmental achievements, less vulnerability to anxiety, better neurocognitive skills, less vulnerability to psychosis and experience more periods of recovery.


Asunto(s)
Antipsicóticos/uso terapéutico , Esquizofrenia/tratamiento farmacológico , Adolescente , Adulto , Chicago , Femenino , Estudios de Seguimiento , Humanos , Entrevista Psicológica/métodos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Inducción de Remisión/métodos , Prevención Secundaria , Resultado del Tratamiento , Adulto Joven
4.
Acta Psychiatr Scand ; 122(6): 499-506, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20637012

RESUMEN

OBJECTIVE: Despite increasing interest in cognitive dysfunction in bipolar disorder, little is known about its impact on functional outcome relative to affective symptoms. METHOD: A total of 33 bipolar I subjects were evaluated at index hospitalization and prospectively followed up 15 years later. Affective symptoms, cognition, global functioning, work, and social adjustment were assessed at follow-up and analyzed by linear regression. RESULTS: Global functional impairment was significantly associated with poor performance on a cognitive measure of processing speed (WAIS Digit Symbol). Digit symbol performance also was the sole significant predictor of social functioning. Neither symptom severity nor course of illness features significantly contributed to global and social functioning. In contrast, verbal learning deficits, recent depression, and lifetime hospitalizations all were independently associated with work disability. CONCLUSION: Processing speed is robustly associated with social and global functioning in bipolar disorder. Poor work functioning is significantly related to subsyndromal depression, course of illness, and verbal learning deficits. Cognitive and mood symptoms warrant consideration as independent determinants of functioning in patients with bipolar disorder many years after an index manic episode.


Asunto(s)
Trastorno Bipolar/epidemiología , Trastornos del Conocimiento/epidemiología , Ajuste Social , Adulto , Trastorno Bipolar/diagnóstico , Trastorno Bipolar/psicología , Chicago/epidemiología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/psicología , Comorbilidad , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/epidemiología , Trastorno Depresivo/psicología , Empleo/psicología , Empleo/estadística & datos numéricos , Función Ejecutiva , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Pruebas Neuropsicológicas/estadística & datos numéricos , Estudios Prospectivos , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
5.
Schizophr Bull ; 27(3): 527-37, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11596853

RESUMEN

This study assessed differences in negative symptom presentation between schizophrenia/schizoaffective, other psychotic, and depressed patients over a 10-year followup period. One hundred fifty individuals with schizophrenia or schizoaffective disorders (SZ/SZAF), other psychotic disorders (OP), and depressed patients (DP) were assessed at index hospitalization, then reassessed at 4.5-year, 7.5-year, and 10-year followups. SZ/SZAF patients significantly differed from DP patients in frequency and persistence of negative symptoms but were not significantly different from the OP group. Negative symptoms were not associated with depression in any diagnostic group. Dosage, but not simple use, of conventional antipsychotic medications was related to severity of symptoms in the SZ/SZAF group. Although negative symptoms were typically most severe and most common in the SZ/SZAF subjects in comparison to the DP patients, there were few statistically significant differences in the phenomenology of negative symptoms between the OP and SZ/SZAF groups. The data are consistent with a model that identifies negative symptoms as common to mental illnesses generally, with particularly high rates in psychotic illnesses.


Asunto(s)
Trastornos Psicóticos/diagnóstico , Esquizofrenia/diagnóstico , Adulto , Antipsicóticos/uso terapéutico , Trastorno Depresivo/psicología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Trastornos Psicóticos/tratamiento farmacológico , Esquizofrenia/tratamiento farmacológico
6.
Am J Psychiatry ; 158(8): 1265-70, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11481161

RESUMEN

OBJECTIVE: To assess the risk for subsequent development of mania or hypomania, the authors conducted a 15-year prospective follow-up study of a large, young cohort of patients originally hospitalized for unipolar major depression. METHOD: Patients who were hospitalized for unipolar major depression (N=74; mean age=23.0 years, SD=3.8) were assessed prospectively as inpatients and then followed up five times over 15 years, at approximately 2, 5, 8, 11, and 15 years after discharge. Manic or hypomanic episodes, medications, and rehospitalizations were determined by standardized assessments at each follow-up. Polarity conversions were evaluated by survival analyses. RESULTS: By the 15-year follow-up, 27% of the study group had developed one or more distinct periods of hypomania, while another 19% had at least one episode of full bipolar I mania. Depressed patients with psychosis at the index depressive episode were significantly more likely than nonpsychotic patients to demonstrate subsequent mania or hypomania at follow-up. Those with family histories of bipolar illness showed a nonsignificantly higher rate of switching to mania or hypomania. Spontaneous and antidepressant-associated manias did not differ in frequency. Fewer than one-half of the patients who showed an eventual bipolar course had received prescriptions for mood stabilizers in any follow-up year. CONCLUSIONS: Young depressed inpatients with psychotic features may be at especially high risk for eventually developing mania. The probability for developing a bipolar spectrum disorder increases in linear fashion for patients at risk for polarity conversion during the first 10-15 years after an index depressive episode.


Asunto(s)
Trastorno Bipolar/epidemiología , Trastorno Depresivo/epidemiología , Hospitalización , Adulto , Trastorno Bipolar/diagnóstico , Estudios de Cohortes , Comorbilidad , Trastorno Depresivo/diagnóstico , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Probabilidad , Pronóstico , Estudios Prospectivos , Factores de Riesgo , Análisis de Supervivencia
7.
J Orthop Res ; 19(3): 428-35, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11398856

RESUMEN

The impact of age and ovariectomy on the healing of femoral fractures was studied in three groups of female rats at 8, 32 and 50 weeks of age at fracture. In the two older groups, the rats had been subjected to ovariectomy or sham surgery at random at 26 weeks of age. At fracture, all rats received unilateral intramedullary pinning of one femur and a middiaphyseal fracture. Rigidity and breaking load of the femora were evaluated at varying times up to 24 weeks after fracture induction by three-point bending to failure. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. In the youngest group, 8-week-old female rats regained normal femoral rigidity and breaking load by 4 weeks after fracture. They exceeded normal contralateral values by 8 weeks after fracture. In the middle group, at 32 weeks of age, fractures were induced, and the femora were harvested at 6 and 12 weeks after fracture. At 6 weeks after fracture there was partial restoration of rigidity and breaking load. At 12 weeks after fracture, only the sham-operated rats had regained normal biomechanical values in their fractured femora, while the fractured femora of the ovariectomized rats remained significantly lower in both rigidity and breaking load. In contrast, for the oldest group of rats, 50 weeks old at fracture, neither sham-operated nor ovariectomized rats regained normal rigidity or breaking load in their fractured femora within the 24 weeks in which they were studied. In all fractured bones, there was a significant increase in BMD over the contralateral intact femora due to the increased bone tissue and bone mineral in the fracture callus. Ovariectomy significantly reduced the BMD of the intact femora and also reduced the gain in BMD by the fractured femora. In conclusion, age and ovariectomy significantly impair the process of fracture healing in female rats as judged by measurements of rigidity and breaking load in three-point bending and by accretion of mineral into the fracture callus.


Asunto(s)
Envejecimiento/fisiología , Densidad Ósea/fisiología , Fracturas del Fémur/fisiopatología , Curación de Fractura/fisiología , Ovariectomía , Resistencia a la Tracción/fisiología , Absorciometría de Fotón , Animales , Callo Óseo/metabolismo , Femenino , Fracturas del Fémur/metabolismo , Docilidad , Ratas , Ratas Sprague-Dawley , Estrés Mecánico , Soporte de Peso
8.
J Int Neuropsychol Soc ; 7(1): 20-6, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11253838

RESUMEN

We evaluated auditory working memory in 41 HIV-seropositive (HIV+) and 37 HIV-seronegative (HIV-) male drug users, employing a modified version of the Letter-Number Span Task developed by Gold and colleagues. We added a control condition to the standard task in order to evaluate more directly the contribution of the processing component to the working memory deficits with the effects of storage demands minimized. HIV+ subjects performed significantly more poorly compared to controls on an index of working memory processing derived from raw scores obtained under the two testing conditions. These findings are consistent with our previous reports that HIV-related working memory deficits are evident across multiple informational domains; further, the deficit appears to involve multiple-component functions of working memory. Converging findings from recent working memory studies and from primate and neuroimaging investigations suggest that functional abnormalities of prefrontal cortex should receive greater emphasis in models of neurocognitive aspects of HIV-1 infection, which have typically emphasized "subcortical" deficits.


Asunto(s)
Complejo SIDA Demencia/complicaciones , Percepción Auditiva/fisiología , Seropositividad para VIH/complicaciones , Trastornos de la Memoria/etiología , Complejo SIDA Demencia/fisiopatología , Complejo SIDA Demencia/psicología , Depresión/etiología , VIH-1 , Humanos , Masculino , Trastornos de la Memoria/diagnóstico , Persona de Mediana Edad , Pruebas Neuropsicológicas , Corteza Prefrontal/fisiopatología , Trastornos Relacionados con Sustancias/complicaciones
9.
Psychiatry Res ; 97(1): 61-77, 2000 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-11104858

RESUMEN

This study investigated the nature, independence, and stability of schizophrenia's syndrome factors and depression at 2, 4.5, 7.5 and 10 years post-index hospitalization. At the four follow-ups, 71 patients (48 with schizophrenia and 23 with schizoaffective disorder) were assessed for symptoms hypothesized to constitute the reality distortion, disorganized, and negative factors of schizophrenia. At the last three follow-ups, the patients were also assessed for symptoms of depression. Factor analyses of schizophrenia symptoms revealed more than three syndrome factors at each follow-up. Longitudinally, reality distortion was a stable and relatively independent factor. The negative syndrome was independent but was bifurcated into two dimensions, interpreted as social/emotional withdrawal and diminished movement/expressiveness. Although signs of disorganization were not unified or independent early in schizophrenia's course, speech/thought disorder, disorganized affect, and poverty of speech content coalesced to form a disorganization factor by the 7.5-year follow-up. When depressive symptoms were added to the analyses, depression constituted an independent and stable dimension of schizophrenia over time. Each schizophrenia factor demonstrated a unique longitudinal course. Courses included stable symptom consistency (reality distortion), evolving symptom convergence (disorganization), and recurrent bifurcation and symptom instability (the negative syndrome).


Asunto(s)
Depresión/etiología , Depresión/psicología , Esquizofrenia/complicaciones , Psicología del Esquizofrénico , Adulto , Enfermedad Crónica , Factores de Confusión Epidemiológicos , Depresión/diagnóstico , Progresión de la Enfermedad , Análisis Factorial , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Estudios Prospectivos , Escalas de Valoración Psiquiátrica , Esquizofrenia/tratamiento farmacológico , Índice de Severidad de la Enfermedad , Factores de Tiempo
10.
Br J Psychiatry ; 177: 421-6, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11059995

RESUMEN

BACKGROUND: It is unclear whether outcome in schizoaffective disorders is more similar to schizophrenia or affective disorders. AIMS: To provide longitudinal data on clinical course and outcome in schizoaffective disorders versus schizophrenia and affective disorders, and determine whether mood-incongruent psychotic symptoms have negative prognostic implications. METHOD: A total of 210 patients with schizoaffective disorders, schizophrenia, bipolar manic disorders and depression were assessed at hospitalisation and then followed up four times over 10 years. RESULTS: At all four follow-ups, fewer patients with schizoaffective disorders than with schizophrenia showed uniformly poor outcome. Patients with mood-incongruent psychotic symptoms during index hospitalisation showed significantly poorer subsequent outcome (P < 0.05). CONCLUSIONS: Schizoaffective outcome was better than schizophrenic outcome and poorer than outcome for psychotic affective disorders. Mood-incongruent psychotic symptoms have negative prognostic implications. The results could fit a symptom dimension view of schizoaffective course.


Asunto(s)
Trastornos Psicóticos/diagnóstico , Enfermedad Aguda , Adulto , Trastornos Psicóticos Afectivos/diagnóstico , Trastornos Psicóticos Afectivos/tratamiento farmacológico , Trastornos Psicóticos Afectivos/rehabilitación , Análisis de Varianza , Femenino , Estudios de Seguimiento , Hospitalización/estadística & datos numéricos , Humanos , Masculino , Readmisión del Paciente/estadística & datos numéricos , Pronóstico , Estudios Prospectivos , Trastornos Psicóticos/tratamiento farmacológico , Trastornos Psicóticos/rehabilitación , Esquizofrenia/diagnóstico , Esquizofrenia/tratamiento farmacológico , Esquizofrenia/rehabilitación , Resultado del Tratamiento
11.
Schizophr Bull ; 26(4): 879-91, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11087020

RESUMEN

This research studied hypotheses that positive thought disorder in schizophrenia is influenced by patients' not taking in immediate target contextual material, thereby losing vital cues that guide thought processes. We assessed 164 acute inpatients (including 55 schizophrenia and 31 bipolar disorder patients), using standardized measures of thought disorder. We also used new measures that assessed (1) total ignoring of context, and (2) straying from the context. Results were as follows: (1) only 9 percent of the schizophrenia patients showed strong evidence of completely ignoring the external context; (2) straying from the external context while simultaneously maintaining part of the context was significantly more common than complete absence of context (p < 0.01); (3) patients with thought disorder strayed from the context significantly more than patients without thought disorder (p < 0.001); and (4) straying from the context was involved in the thought disorder of some, but not all, schizophrenia and mania patients. The data suggest that thought disorder in schizophrenia is not typically due to a failure to "hear" or to take in the relevant contextual material necessary for an appropriate response. Loss of context is involved in some, but not all, thought disorder in schizophrenia and mania.


Asunto(s)
Trastorno Bipolar/psicología , Cognición , Señales (Psicología) , Psicología del Esquizofrénico , Pensamiento , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Memoria a Corto Plazo
12.
J Int Neuropsychol Soc ; 6(5): 548-55, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10932474

RESUMEN

Recent evidence suggests that HIV-seropositive drug users are impaired on tasks of visuospatial working memory compared with drug users seronegative for HIV. In the current study we evaluated the performance of 30 HIV-seropositive male drug users and 30 risk-matched seronegative controls on two measures of verbal working memory, the Listening Span and the verbal Self Ordered Pointing Task. Impaired working memory performance was significantly more common among HIV-seropositive persons compared to controls, with the highest incidence of deficit among symptomatic participants. These findings indicate that working memory deficits in persons with HIV are not domain-specific and can be demonstrated reliably in drug users.


Asunto(s)
Seropositividad para VIH/psicología , Memoria a Corto Plazo/fisiología , Trastornos Relacionados con Sustancias/psicología , Aprendizaje Verbal/fisiología , Adulto , Ensayo de Inmunoadsorción Enzimática , Humanos , Masculino , Estudios Prospectivos , Desempeño Psicomotor/fisiología
13.
Sci Total Environ ; 251-252: 55-81, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847153

RESUMEN

This paper examines spatial and temporal variability in freshwater inputs of trace elements and major ions to the tidal reaches of the River Tweed. The relationships between concentrations of major ions and trace elements (in dissolved and acid-available particulate forms) and flow are examined, and a simple two-component endmember mixing analysis performed to link river water chemistry to catchment sources, and to identify whether within-river processes modify concentrations to produce non-conservative behaviour. The results indicate that most dissolved major ions and trace elements behave conservatively in the lower reaches of the River Tweed, the variability in concentrations being dominated by hydrology and the existence of different high-flow and low-flow endmember runoff chemistries. This suggests that the variability in concentration of most dissolved trace elements and major ions in the lower Tweed can be modelled using simple mixing relationships. However, the relationships between pH, Ca, Mg and Gran alkalinity show pronounced non-conservative behaviour, indicating the importance of understanding within-river process for modelling these determinants. The non-conservative behaviour identified is related to biological controls and the resultant diurnal variations in pH which promote daytime removal of Ca from solution by precipitation of calcium carbonate (and corresponding removal of Mg by co-precipitation) during extreme low-flow conditions and algal blooms during the summer.


Asunto(s)
Eutrofización , Movimientos del Agua , Concentración de Iones de Hidrógeno , Iones , Modelos Teóricos , Oligoelementos , Reino Unido , Tiempo (Meteorología)
14.
Sci Total Environ ; 251-252: 335-67, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847172

RESUMEN

The water quality of a major river system, the River Trent, which flows into the Humber estuary and drains large centres of population and industry in central England, is examined in terms of trace element, nutrient, major-ion, suspended sediment and carbon concentrations and set within the context of the transition from non-tidal to the tidal freshwater reaches. Detailed investigation of the water quality variability in the non-tidal river Trent has revealed mainly simple patterns in dissolved chemical concentrations, controlled largely by hydrology and the mixing of baseflow and stormflow endmember chemistries. However, silicon, carbon and nitrate show much more complex behaviour, as concentrations of these chemical determinands are regulated by in-stream biological processes. Major increases in concentrations of suspended solids and acid-available particulate (AAP) trace elements are shown to be linked to tidal mobilization of sediment and the location of the 'turbidity maximum'. Reductions in the concentrations of AAP trace elements per gram of suspended sediment suggest the mobilization of a different sediment type with a lower trace element content, which may result from: (i) a secondary sediment source; or (ii) mobilization of coarser-grained sediment under the stronger tidal hydrodynamic forces. Increased correlations for AAP-trace element interrelationships downstream suggest increasing simplicity of mixing relationships.

15.
Sci Total Environ ; 251-252: 441-57, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847177

RESUMEN

Water quality information is presented for the River Thames 34 km downstream of the market town of Oxford in Oxfordshire to provide an overview of the hydrochemical functioning of a major agriculturally impacted river entering the North Sea. The data, which cover the period from the spring of 1997 to the spring of 1999, relate to three types of data. These types are: (1) weekly spot sampling for determination of major, minor and trace elements, pH, alkalinity and herbicides; (2) tri-weekly spot sampling for pH, alkalinity and dissolved silicon; and (3) continuous measurements of pH and dissolved oxygen. Calcium and bicarbonate provide, respectively, the dominant cation and anion in solution and their compositions remain relatively constant through time, irrespective of flow levels. In contrast, many determinands show seasonally related fluctuations. Concentrations for most of the major anions, sodium, potassium as well as soluble reactive phosphorus and several soluble trace elements such as boron, antimony, arsenic and molybdenum decrease as flow increases. A reverse pattern is observed for nitrate, some herbicides and trace elements associated with particulate phases: concentrations increase with increasing flow. These patterns reflect the influence of: (1) a calcium carbonate rich groundwater system which provides the main stream flow component; (2) dilution of point source pollutant inputs associated with sewage and possibly light industry at high flows for several major, nutrient and trace elements; (3) enhanced nitrate and herbicide runoff from agricultural land at high flows; (4) enhanced microparticulate trace metal levels associated with increased suspended sediment loads at high flows; and (5) biological processes which affect pH, dissolved silicon, dissolved carbon dioxide and dissolved oxygen levels. An examination of soluble reactive phosphorus (SRP) and boron relationships reveals a reduction in concentrations for SRP associated possibly with phosphorus removal from a major sewage treatment works on an upstream tributary of the Thames, the Thame.

16.
Sci Total Environ ; 251-252: 459-75, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847178

RESUMEN

The water quality of a tributary of the Thames, the Pang, draining a rural part of the Thames basin is described and related to the influences of inputs from farming activity and groundwater from the underlying chalk aquifer as modified by biological within-stream processes. The groundwater inputs ensures that the waters are calcium and bicarbonate bearing and have relatively uniform concentrations. Agricultural inputs result in enhanced levels of nutrients, nitrate and soluble reactive phosphorus (SRP) in particular. For nitrate, the concentrations are higher during the winter months due to increased surface runoff. In contrast, SRP shows a more erratic behaviour with higher concentrations occurring during the early storm hydrograph rise following summer baseflow recession. Within the stream, biological activity results in: (a) marked diurnal fluctuations in the dissolved levels of carbon dioxide and oxygen; (b) a strong seasonal pattern in chlorophyll a levels; and (c) dissolved silica concentration reductions during the early spring period. Carbon dioxide levels are particularly high in the groundwater (typically approximately 60 times the atmospheric value) as observed at a spring discharge. However, within the stream, considerable degassing occurs although values remain an order of magnitude above atmospheric pressure. The findings are discussed in the context of the water quality functioning of agriculturally and sewage impacted southern eastern UK rivers. For example, the work shows that unlike for riverine systems with point sewage discharges or limited groundwater storage, there is a very poor link between chemical concentrations and flow even for components such as SRP and boron which are often connected to sewage discharges.


Asunto(s)
Agricultura , Dióxido de Carbono/análisis , Clorofila/análisis , Aguas del Alcantarillado , Contaminación del Agua/análisis , Presión Atmosférica , Calcio/análisis , Clorofila A , Inglaterra , Monitoreo del Ambiente , Concentración de Iones de Hidrógeno , Nitrógeno/análisis , Nitrógeno/metabolismo , Fósforo/análisis , Fósforo/metabolismo , Estaciones del Año , Microbiología del Agua
17.
Sci Total Environ ; 251-252: 477-95, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847179

RESUMEN

The water quality of seven sites on the upper reaches of the River Kennet round the market town of Marlborough is described and related to the introduction of phosphorus treatment of effluent from Marlborough sewage treatment works (STW). The River Kennet is mainly groundwater-fed from a Cretaceous chalk aquifer and hence the river water is calcium- and bicarbonate-bearing and has a relatively constant composition of many major water quality determinants. In-stream biological activity gives rise to marked diurnal fluctuations in pH (of approx. 0.8 units). Dissolved carbon dioxide and dissolved oxygen also show marked diurnal fluctuations. Dissolved carbon dioxide varies from approximately 10 to 70 times atmospheric pressure, indicating net release of carbon dioxide and the dominance of heterotrophic (respiratory) processes over autotrophic processes (photosynthesis). Much of the excess carbon dioxide is probably associated with carbon dioxide laden groundwater inputs and the relatively short within-stream residence times ensures only limited degassing to the atmosphere. Diurnal fluctuations in dissolved oxygen vary from approximately 20% to 200% saturation. For both dissolved carbon dioxide and dissolved oxygen, the amplitude of fluctuations is much lower during the winter period, when biological activity is at its lowest. The concentrations of soluble reactive phosphorus (SRP), total phosphorus (TP) and boron increase markedly just downstream of the sewage works as a result of this point source input. These concentrations slowly decline further downstream as additional groundwater inputs dilute the effluent further. The introduction of chemical treatment of sewage effluent for phosphorus reduction at Marlborough STW resulted in a marked decrease in within-river SRP and TP concentrations to levels approximately the same as those upstream of the STW. A comparison of SRP and boron concentrations reveals a reduction in in-stream SRP concentrations by approximately 75% following effluent treatment. In terms of within-river processes controlling in-stream phosphorus concentrations, previous studies have indicated that one potentially important mechanism within calcium bicarbonate bearing rivers may be related to co-precipitation of phosphorus with calcium carbonate (calcite). The present study shows that the waters are oversaturated with respect to calcium carbonate, that no equilibrium conditions exist and that phosphorus removal has led to undetectable changes in calcium carbonate oversaturation. Hence, it is concluded that the primary changes in phosphorus levels within the river is directly associated with changing point source contributions from the STW and physical dilution within the river. However (1) the results relate to only the first year of study and subsequent differences may become apparent and (2) reactions between the water column and plant and bottom sediment interfaces may be important in regulating phosphorus fluxes within the river. The results presented in this paper mark a pilot phase of a longer-term initiative and this paper provides a background setting. The paper discusses the longer-term objectives and important gaps in knowledge of the system that requires further address.


Asunto(s)
Fósforo/análisis , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisis , Contaminación del Agua/prevención & control , Inglaterra , Monitoreo del Ambiente , Concentración de Iones de Hidrógeno , Fósforo/farmacocinética , Estaciones del Año , Microbiología del Agua
18.
Sci Total Environ ; 251-252: 497-510, 2000 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-10847180

RESUMEN

Small-scale spatial dissolved oxygen concentrations were measured on three rivers by taking a number of transects along a river reach. Temporal (diurnal) variations were measured by use of continuous (15-min) monitors located at the mid-transect of the spatial observations. Spatial variation of dissolved oxygen concentrations were found to be relatively small (approx. +/- 10% dissolved oxygen) and biologically insignificant compared to diurnal changes under conditions of high productivity (approx. +/- 60% dissolved oxygen). The diurnal curves were analysed in order to estimate values of reaeration, photosynthesis and respiration on a daily basis for almost 3 months using process-based analytical techniques (the Delta and Hornberger and Kelly methods). The River Kennet was shown to be the most productive river followed by the River Pang and then the River Thames. The patterns of reaeration, photosynthesis and respiration and the behaviour of the three rivers are discussed.


Asunto(s)
Metabolismo , Oxígeno/análisis , Fotosíntesis , Inglaterra , Oxígeno/metabolismo , Plantas , Factores de Tiempo , Agua/química , Microbiología del Agua
19.
Suicide Life Threat Behav ; 29(1): 10-24, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10322617

RESUMEN

The present research explores the relationship of positive symptoms, negative symptoms, and posthospital functioning to subsequent suicidal behavior over a 7 1/2-year period, and examines whether these patterns vary with diagnosis. The results support a multifactor model of suicide risk. Both psychosis and poor functioning show some relationship to later suicidal activity for both schizophrenic and schizoaffective patients. Psychosis may remain a risk factor for suicidal activity for schizoaffective patients, even when functioning is partialed out. This is in contrast to the schizophrenia patients, for whom funtioning seems to mediate the effects of psychosis on later suicidality. In general, adequacy of overall posthospital functioning mediates the effects of some risk factors on suicidal activity within different diagnostic groups.


Asunto(s)
Trastornos del Humor/epidemiología , Escalas de Valoración Psiquiátrica/normas , Esquizofrenia/epidemiología , Prevención del Suicidio , Suicidio/estadística & datos numéricos , Adulto , Edad de Inicio , Distribución de Chi-Cuadrado , Comorbilidad , Deluciones/epidemiología , Femenino , Estudios de Seguimiento , Alucinaciones , Humanos , Estudios Longitudinales , Masculino , Trastornos del Humor/diagnóstico , Negativismo , Valor Predictivo de las Pruebas , Trastornos Psicóticos/epidemiología , Factores de Riesgo , Esquizofrenia/diagnóstico , Intento de Suicidio/estadística & datos numéricos
20.
J Nerv Ment Dis ; 187(5): 281-9, 1999 May.
Artículo en Inglés | MEDLINE | ID: mdl-10348082

RESUMEN

Recent findings have linked impairments in social performance among individuals with schizophrenia to deficits in cognition. However, one component of cognition, thought disorder (TD), has received little attention in its association with social functioning. The current investigation examined the cross-sectional and predictive relationships between bizarre-idiosyncratic thought and psychosocial functioning throughout the early course of schizophrenia and compared these relationships to those observed among individuals with affective disorders (i.e., bipolar disorder, manic type, and major depression without psychotic features). Participants were assessed on TD, work, and social functioning using standardized procedures across three follow-ups over an 8-year period. The cross-sectional relationships between TD and impairment in work performance were generally significant. TD also significantly predicted subsequent work functioning years later. Less support was found for the relationship between TD and social functioning. Finally, the relationship between TD and work performance appeared to be more consistent over time for the subjects with schizophrenia compared to those with affective disorders. The results suggest that techniques which minimize TD may have implications for occupational functioning among persons with chronic psychiatric disorders.


Asunto(s)
Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Ajuste Social , Adaptación Psicológica , Adolescente , Adulto , Trastorno Bipolar/diagnóstico , Trastorno Bipolar/psicología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/psicología , Estudios Transversales , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/psicología , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Probabilidad , Escalas de Valoración Psiquiátrica , Esquizofrenia/rehabilitación , Conducta Social , Trabajo/psicología
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