Entomological assessment of hessian fabric transfluthrin vapour emanators for protecting against outdoor-biting Aedes aegypti in coastal Tanzania.

BACKGROUND: A low technology emanator device for slowly releasing vapour of the volatile pyrethroid transfluthrin was recently developed in Tanzania that provides robust protection against night biting Anopheles and Culex vectors of malaria and filariasis for several months. Here these same emanator devices were assessed in Dar es Salaam city, as a means of protection against outdoor-biting Aedes (Stegomia) aegypti, the most important vector of human arboviruses worldwide, in parallel with similar studies in Haiti and Brazil. METHODS: A series of entomological experiments were conducted under field and semi-field conditions, to evaluate whether transfluthrin emanators protect against wild Ae. aegypti, and also compare the transfluthrin responsiveness of Ae. aegypti originating from wild-caught eggs to established pyrethroid-susceptible Ae. aegypti and Anopheles gambiae colonies. Preliminary measurements of transfluthrin vapour concentration in air samples collected near treated emanators were conducted by gas chromatography-mass spectrometry. RESULTS: Two full field experiments with four different emanator designs and three different transfluthrin formulations consistently indicated negligible reduction of human landing rates by wild Ae. aegypti. Under semi-field conditions in large cages, 50 to 60% reductions of landing rates were observed, regardless of which transfluthrin dose, capture method, emanator placement position, or source of mosquitoes (mildly pyrethroid resistant wild caught Ae. aegypti or pyrethroid-susceptible colonies of Ae. aegypti and An. gambiae) was used. Air samples collected immediately downwind from an emanator treated with the highest transfluthrin dose (15g), contained 12 to 19 µg/m3 transfluthrin vapour. CONCLUSIONS: It appears unlikely that the moderate levels of pyrethroid resistance observed in wild Ae. aegypti can explain the modest-to-undetectable levels of protection exhibited. While potential inhalation exposure could be of concern for the highest (15g) dose evaluated, 3g of transfluthrin appears sufficient to achieve the modest levels of protection that were demonstrated entomologically. While the generally low levels of protection against Aedes reported here from Tanzania, and from similar entomological studies in Haiti and Brazil, are discouraging, complementary social science studies in Haiti and Brazil suggest end-users perceive valuable levels of protection against mosquitoes. It therefore remains unclear whether transfluthrin emanators have potential for protecting against Aedes vectors of important human arboviruses.

Impacts of LULC and climate changes on hydropower generation and development: A systematic review.

There is a growing concern on a global scale that the world should transition towards the utilisation of energy-efficient technologies. Hydropower plays a very significant part in the fight against climate change, and as a result, it lessens the impact that climate changewill have on our ability to achieve the Sustainable Development Goals (SDGs). Both the effectiveness of hydropower generation and the amount of streamflow are impacted by climate change as well as land use and land cover (LULC). Accordingly, the purpose of this study is to conduct a literature review on the topic of the past and future effects of climate, land use, and land cover changes on hydropower generation. This review will be based on the entries found in a number of reliable databases. A systematic literature review was carried out to analyse how LULC and climate change will affect hydropower generation and development. The research was based on 158 pieces of relevant literature that had been reviewed by experts and indexed in Scopus, Google Scholar, and ScienceDirect. The review was carried out to determine three goals in mind: the impact of climate change on hydropower generation and development; the impact of climate change on streamflow; and the combined impact of changes in climate and changes in LULC on hydropower. The findings bring to light the primary factors contributing to climate change as well as shifts in LULC which are essential to the generation of hydropower on all scales. The study identifies factors such as precipitation, temperature, floods, and droughts as examples of climate change. Deforestation, afforestation, and urbanisation are identified as the primary causes of changes in LULC over the past several decades. These changes have a negative impact on the generation and development of hydropower.

Hydrologic response to climate change in the Densu River Basin in Ghana.

Climate change continues to pose a threat to the sustainability of water resources. Global warming can have several effects on the water resources and water demands in the Densu River Basin especially household water use and agriculture use among several others. However, the extents to which the hydrology of the Densu River Basin is will be altered in the future remains unknown. In this research, the Water Evaluation and Planning (WEAP21) system was used to study the impacts of future climate change on water resources in the Densu River Basin. Future climate data (rainfall and temperature) for the period 2051-2080 was generated from the Swedish Meteorological and Hydrological Institute's climate models (ICHEC-EC-EARTH and RCA4) for RCP4.5 scenario under CORDEX experiment. The results of the study indicate that the Densu River Basin will experience a temperature increase by 8.23% and a 17% reduction in rainfall resulting in 58.3% reduction in water resources in the area. The climate change impact analysis indicates a reduction in the river streamflow due to decrease in rainfall. It is recommended that future research on climate change adaptation for water management in the Densu River Basin should be conducted.

Mapping suitability for rice production in inland valley landscapes in Benin and Togo using environmental niche modeling.

Inland valleys (IVs) in Africa are important landscapes for rice cultivation and are targeted by national governments to attain self-sufficiency. Yet, there is limited information on the spatial distribution of IVs suitability at the national scale. In the present study, we developed an ensemble model approach to characterize the IVs suitability for rainfed lowland rice using 4 machine learning algorithms based on environmental niche modeling (ENM) with presence-only data and background sample, namely Boosted Regression Tree (BRT), Generalized Linear Model (GLM), Maximum Entropy (MAXNT) and Random Forest (RF). We used a set of predictors that were grouped under climatic variables, agricultural water productivity and soil water content, soil chemical properties, soil physical properties, vegetation cover, and socio-economic variables. The Area Under the Curves (AUC) evaluation metrics for both training and testing were respectively 0.999 and 0.873 for BRT, 0.866 and 0.816 for GLM, 0.948 and 0.861 for MAXENT and 0.911 and 0.878 for RF. Results showed that proximity of inland valleys to roads and urban centers, elevation, soil water holding capacity, bulk density, vegetation index, gross biomass water productivity, precipitation of the wettest quarter, isothermality, annual precipitation, and total phosphorus among others were major predictors of IVs suitability for rainfed lowland rice. Suitable IVs areas were estimated at 155,000-225,000 Ha in Togo and 351,000-406,000 Ha in Benin. We estimated that 53.8% of the suitable IVs area is needed in Togo to attain self-sufficiency in rice while 60.1% of the suitable IVs area is needed in Benin to attain self-sufficiency in rice. These results demonstrated the effectiveness of an ensemble environmental niche modeling approach that combines the strengths of several models.

Mosquito electrocuting traps for directly measuring biting rates and host-preferences of Anopheles arabiensis and Anopheles funestus outdoors.

BACKGROUND: Mosquito biting rates and host preferences are crucial determinants of human exposure to vector-borne diseases and the impact of vector control measures. The human landing catch (HLC) is a gold standard method for measuring human exposure to bites, but presents risks to participants by requiring some exposure to mosquito vectors. Mosquito electrocuting traps (METs) represent an exposure-free alternative to HLCs for measuring human exposure to malaria vectors. However, original MET prototypes were too small for measuring whole-body biting rates on humans or large animals like cattle. Here a much larger MET capable of encompassing humans or cattle was designed, and its performance was evaluated relative to both the original small MET and HLC and for quantifying malaria vector host preferences. METHODS: Human landing catch, small human-baited METs (MET-SH), and large METs baited with either a human (MET-LH) or calves (MET-LC) were simultaneously used to capture wild malaria vectors outdoors in rural southern Tanzania. The four capture methods were compared in a Latin-square design over 20 nights. Malaria vector host preferences were estimated through comparison of the number of mosquitoes caught by large METs baited with either humans or cattle. RESULTS: The MET-LH caught more than twice as many Anopheles arabiensis than either the MET-SH or HLC. It also caught higher number of Anopheles funestus sensu lato (s.l.) compared to the MET-SH or HLC. Similar numbers of An. funestus sensu stricto (s.s.) were caught in MET-LH and MET-SH collections. Catches of An. arabiensis with human or cattle-baited large METs were similar, indicating no clear preference for either host. In contrast, An. funestus s.s. exhibited a strong, but incomplete preference for humans. CONCLUSIONS: METs are a sensitive, practical tool for assessing mosquito biting rates and host preferences, and represent a safer alternative to the HLC. Additionally these findings suggest the HLC underestimate whole-body human exposure. MET collections indicated the An. funestus s.s. population in this setting had a higher than expected attack rate on cattle, potentially making eliminating of this species more difficult with human-targetted control measures. Supplementary vector control tools targetted at livestock may be required to effectively tackle this species.

An improved mosquito electrocuting trap that safely reproduces epidemiologically relevant metrics of mosquito human-feeding behaviours as determined by human landing catch.

BACKGROUND: Reliable quantification of mosquito host-seeking behaviours is required to determine the efficacy of vector control methods. For malaria, the gold standard approach remains the risky human landing catch (HLC). Here compare the performance of an improved prototype of the mosquito electrocuting grid trap (MET) as a safer alternative with HLC for measuring malaria vector behaviour in Dar es Salaam, Tanzania. METHODS: Mosquito trapping was conducted at three sites within Dar es Salaam representing a range of urbanicity over a 7-month period (December 2012-July 2013, 168 sampling nights). At each site, sampling was conducted in a block of four houses, with two houses being allocated to HLC and the other to MET on each night of study. Sampling was conducted both indoors and outdoors (from 19:00 to 06:00 each night) at all houses, with trapping method (HLC and MET) being exchanged between pairs of houses at each site using a crossover design. RESULTS: The MET caught significantly more Anopheles gambiae sensu lato than the HLC, both indoors (RR [95 % confidence interval (CI)]) = 1.47 [1.23-1.76], P < 0.0001 and outdoors = 1.38 [1.14-1.67], P < 0.0001). The sensitivity of MET compared with HLC did not detectably change over the course of night for either An. gambiae s.l. (OR [CI]) = 1.01 [0.94-1.02], P = 0.27) or Culex spp. (OR [CI]) = 0.99 [0.99-1.0], P = 0.17) indoors and declined only slightly outdoors: An. gambiae s.l. (OR [CI]) = 0.92 [0.86-0.99], P = 0.04), and Culex spp. (OR [CI]) = 0.99 [0.98-0.99], P = 0.03). MET-based estimates of the proportions of mosquitoes caught indoors (P i ) or during sleeping hours (P fl ), as well as the proportion of human exposure to bites that would otherwise occurs indoors (π i ), were statistically indistinguishable from those based on HLC for An. gambiae s.l. (P = 0.43, 0.07 and 0.48, respectively) and Culex spp. (P = 0.76, 0.24 and 0.55, respectively). CONCLUSIONS: This improved MET prototype is highly sensitive tool that accurately quantifies epidemiologically-relevant metrics of mosquito biting densities, behaviours and human exposure distribution.

Short-term outcome of substance-induced psychotic disorder in a large UK first episode psychosis cohort.

OBJECTIVE: The incidence and outcome of first-episode substance-induced psychotic disorder (SIPD) are unclear. The study aimed to compare the 1-year outcomes of those given a SIPD diagnosis by clinicians compared to other psychosis diagnoses in a first-episode cohort. METHOD: Data were from a large (n = 1027) cohort of first-episode psychosis (FEP) patients admitted to early intervention services in the UK (National EDEN). Diagnosis, including that of SIPD, was made by treating psychiatrists at baseline using ICD10 criteria. Details on symptoms, functioning, quality of life, relapse and recovery were available at baseline and 12 months. RESULTS: There were 67 cases of SIPD (6.5% of the cohort). At baseline, SIPD patients were no different to other psychoses on symptoms, functioning and quality of life. At 12 months, there was no difference in SIPD and other psychoses on functioning, quality of life or relapse and recovery rates. Levels of psychotic and general symptomatology were similar but depressive symptoms were higher in the SIPD group. CONCLUSIONS: First-episode psychosis patients with a diagnosis of SIPD do not appear to have better outcomes than those with other primary psychotic diagnoses. The higher levels of depressive symptoms may be a specific marker in these patients.

Inappropriate prescribing in a large community-dwelling older population: a focus on prevalence and how it relates to patient and physician characteristics.

WHAT IS KNOWN AND OBJECTIVE: The prescription of potentially inappropriate medications (PIMs) for older adults is a well-known population health concern. Updated country-specific estimates of inappropriate prescribing in older adults using germane explicit criteria are needed to facilitate physician-tailored quality improvement strategies. Therefore, we sought to determine the prevalence of PIMs for older adults in Emilia-Romagna, Italy, using the updated Maio criteria. We also evaluated patient and general practitioner (GP) characteristics related to inappropriate prescribing. METHODS: Older adults (≥ 65) in 2012 were evaluated in a one-year retrospective study using administrative health care data. The 2011 Maio criteria includes 25 medications reimbursed by the Italian National Formulary, in the following categories in terms of severity: 16 medications that 'should always be avoided,' 3 that are 'rarely appropriate,' and 6 that have 'some indications although they are often misused.' To evaluate the extent of associations between patient and GP related characteristics, we used generalized estimating equations with an exchangeable covariance design to fit robust logistic regression models. RESULTS AND DISCUSSION: A total of 865,354 older adults were in the cohort and 28% had at least one PIM. Of the entire cohort, 8%, 10%, and 14% of individuals were prescribed at least one medication that 'should always be avoided,' is 'rarely appropriate,' and has 'some indications but are often misused,' respectively. Older patients (≥ 75) and females were more likely to be exposed to PIMs. 2,923 GPs were identified in the region, each having prescribed at least one PIM, of which older GPs (≥ 56), male GPs, and solo practice GPs were more likely to prescribe PIMs to their older patients. WHAT IS NEW AND CONCLUSION: The high prevalence of PIM exposure among older adults is a substantial issue in the region. Knowing how patient and GP characteristics relate to PIMs exposure may improve the design and targeting of initiatives for improving prescribing safety in this population.

Changes in mental state associated with prison environments: a systematic review.

OBJECTIVE: To develop an understanding of the stability of mental health during imprisonment through review of existing research evidence relating physical prison environment to mental state changes in prisoners. METHOD: A systematic literature search was conducted looking at changes in mental state and how this related to various aspects of imprisonment and the prison environment. RESULTS: Fifteen longitudinal studies were found, and from these, three broad themes were delineated: being imprisoned and aspects of the prison regime; stage of imprisonment and duration of sentence; and social density. Reception into prison results in higher levels of psychiatric symptoms that seem to improve over time; otherwise, duration of imprisonment appears to have no significant impact on mental health. Regardless of social density, larger prisons are associated with poorer mental state, as are extremes of social density. CONCLUSION: There are large gaps in the literature relating prison environments to changes in mental state; in particular, high-quality longitudinal studies are needed. Existing research suggests that although entry to prison may be associated with deterioration in mental state, it tends to improve with time. Furthermore, overcrowding, ever more likely as prison populations rise, is likely to place a particular burden on mental health services.

Usefulness of EQ-5D for evaluation of health-related quality of life in young adults with first-episode psychosis.

PURPOSE: To evaluate the psychometric properties of the EQ-5D and the usefulness of this instrument in psychiatric practice as a measure of health-related quality of life (HRQoL) in a sample of young adults with first-episode psychosis. METHODS: The validity of individual questionnaire items is studied using an Item Response/Latent Trait Theory modeling approach. Sensitivity of response patterns on EQ-5D items to particular diagnostic subtypes of psychosis is investigated using a finite mixture modeling approach through latent class analysis. Finally, a structural equation modeling framework is used to study differential item functioning via a multigroup approach. RESULTS: Results suggest that the data closely correspond to the Rasch Rating Scale Model, and therefore that EQ-5D latent scores are equal interval measures. Despite comprising relatively few items, the instrument yields reliable measures of HRQoL for group comparisons and cost-effectiveness evaluation, but EQ-5D score is too imprecise for the assessment of HRQoL for clinical purposes at the individual level. A significant relationship was found between EQ-5D responses and type of psychosis due to inclusion of item anxiety/depression in EQ-5D. Two items (anxiety/depression, functioning in usual activities) showed an ethnicity bias. CONCLUSIONS: Psychometric evidence confirmed the EQ-5D to be a valid, interval measure that is scalable according to Rasch principles.

Life events preceding suicide by young people.

BACKGROUND: Life events are often reported to precede suicide. This paper aims to determine the frequency, timing and type of life events preceding suicide by young people and those with and without a mental illness. METHOD: Informants, usually family members, were interviewed for a sample of young (less than 35 years) suicides. Information was recorded on events occurring in the 6 months before death. Equivalent information was obtained for living controls who had been matched for age and gender and obtained through the general practices of the suicides. RESULTS: Suicide was associated with life events in the previous 3 months, and particularly in the previous week. Specifically, interpersonal and forensic (being arrested, charged or sentenced) events distinguished suicides and controls. The number of life events in the different time periods under study did not distinguish suicides with and without severe mental illness, although more suicides without a severe mental illness had a reported life event in the week before their death. CONCLUSIONS: Adverse life events frequently precede suicide in young people with and without severe mental illness. However, recent life events may have a lesser causal role in those with severe mental illness. Clinical and health promotion measures to improve the way that young people cope with interpersonal problems and other crises may be an important part of any suicide prevention strategy.

Changes in rates of suicide by car exhaust asphyxiation in England and Wales.

BACKGROUND: Self-asphyxiation using car exhaust gas is a common method of suicide in England and Wales, particularly in young males. The introduction of catalytic converters has reduced the toxicity of car exhausts. The main aims of the study were: to seek evidence of a fall in car exhaust suicides in the general population and in age and gender groups; to relate any fall to changes in car exhaust systems, particularly since legislation on car exhaust emissions in 1993; and to examine rates of suicide by other methods for evidence of method substitution. METHODS: Population study in England and Wales using national suicide statistics for 1987 to 1998. RESULTS: There was a fall in suicide by car exhaust asphyxiation in all age and gender groups. This change was most marked after 1993. The overall population suicide rate (all methods) also fell but there was no overall change in suicides by young males or females. In these groups suicide by hanging increased. CONCLUSIONS: Legislation on catalytic converters appears to have contributed to a fall in car exhaust suicides. However, the effect on overall suicide rates in young people has been reduced by method substitution.

Effect of death of Diana, princess of Wales on suicide and deliberate self-harm.

BACKGROUND: The death of the Princess of Wales in 1997 was followed by widespread public mourning. Such major events may influence suicidal behaviour. AIMS: To assess the impact of the Princess's death on suicide and deliberate self-harm (DSH). METHOD: Analysis, using Poisson regression, of the number of suicides and open verdicts ('suicides') in England and Wales following the Princess's death compared to the 3 months beforehand, and the equivalent periods in 1992-1996. Similar analysis on DSH presentations to a general hospital. RESULTS: Suicides increased during the month following the Princess's funeral (+17.4%). This was particularly marked in females (+33.7%), especially those aged 25-44 years (+45.1%). Suicides did not fall in the week between the death and the funeral. Presentations for DSH increased significantly during the week following the death (+44.3%), especially in females (+65.1%). Examination of case notes suggested that the influence of the death was largely through amplification of personal losses or exacerbation of existing distress. CONCLUSIONS: The death of a major public figure can influence rates of suicidal behaviour. For DSH, the impact may be immediate, but for suicide it may be delayed.

An educational intervention for front-line health professionals in the assessment and management of suicidal patients (The STORM Project).

BACKGROUND: Suicide prevention is a health priority in many countries. Improved management of suicide risk may improve suicide prevention. This study aimed to assess the feasibility of health district-wide training in the assessment and management of people at risk of suicide; and to assess the impact of training on assessment and management skills. METHODS: Staff in three health care settings, namely primary care, accident and emergency departments and mental health services (N = 359), were offered suicide risk management training in a district-wide programme, using a flexible 'facilitator' approach. The main outcomes were the rate of attendance at training, and changes in suicide risk assessment and management skills following training. RESULTS: It was possible to deliver training to 167 health professionals (47 % of those eligible) during a 6 month training period. This included 95 primary care staff (39%), 21 accident and emergency staff(42%) and 51 mental health staff (78%). Of these, 103 (69%) attended all training. A volunteer sample of 28 staff who underwent training showed improvements in skills in the assessment and management of suicide risk. Satisfaction with training was high. The expected costs of district-wide training, if it were able to produce a 2.5% reduction in the suicide rate, would be 99,747 pound sterling per suicide prevented and 3,391 pound sterling per life year gained. CONCLUSIONS: Training in the assessment and management of suicide risk can be delivered to approximately half the targeted staff in primary care, accident and emergency departments and mental health services. The current training package can improve skills and is well accepted. If it were to produce a modest fall in the suicide rate, such training would be cost-effective. However, a future training programme should develop a broader training package to reach those who will not attend.

Suicide within 12 months of contact with mental health services: national clinical survey.

OBJECTIVE: To describe the clinical circumstances in which psychiatric patients commit suicide. DESIGN: National clinical survey. SETTING: England and Wales. SUBJECTS: A two year sample of people who had committed suicide, in particular those who had been in contact with mental health services in the 12 months before death. MAIN OUTCOME MEASURES: Proportion of suicides in people who had had recent contact with mental health services; proportion of suicides in inpatients; proportion of people committing suicide and timing of suicide within three months of hospital discharge; proportion receiving high priority under the care programme approach; proportion who were recently non-compliant and not attending. RESULTS: 10 040 suicides were notified to the study between April 1996 and March 1998, of whom 2370 (24%; 95% confidence interval 23% to 24%) had had contact with mental health services in the year before death. Data were obtained on 2177, a response rate of 92%. In general these subjects had broad social and clinical needs. Alcohol and drug misuse were common. 358 (16%; 15% to 18%) were psychiatric inpatients at the time of death, 21% (17% to 25%) of whom were under special observation. Difficulties in observing patients because of ward design and nursing shortages were both reported in around a quarter of inpatient suicides. 519 (24%; 22% to 26%) suicides occurred within three months of hospital discharge, the highest number occurring in the first week after discharge. 914 (43%; 40% to 44%) were in the highest priority category for community care. 488 (26% excluding people whose compliance was unknown; 24% to 28%) were non-compliant with drug treatment while 486 (28%; 26% to 30%) community patients had lost contact with services. Most people who committed suicide were thought to have been at no or low immediate risk at the final service contact. Mental health teams believed suicide could have been prevented in 423 (22%; 20% to 24%) cases. CONCLUSIONS: Several suicide prevention measures in mental health services are implied by these findings, including measures to improve compliance and prevent loss of contact with services. Inpatient facilities should remove structural difficulties in observing patients and fixtures that can be used in hanging. Prevention of suicide after discharge may require earlier follow up in the community. Better suicide prevention in psychiatric patients is likely to need measures to improve the safety of mental health services as a whole, rather than specific measures for people known to be at high risk.

Mental disorder and clinical care in people convicted of homicide: national clinical survey.

OBJECTIVES: To estimate the rate of mental disorder in those convicted of homicide and to examine the social and clinical characteristics of those with a history of contact with psychiatric services. DESIGN: National clinical survey. SETTING: England and Wales. SUBJECTS: Eighteen month sample of people convicted of homicide. MAIN OUTCOME MEASURES: Offence related and clinical information collected from psychiatric court reports on people convicted of homicide. Detailed clinical data collected on those with a history of contact with psychiatric services. RESULTS: 718 homicides were reported to the inquiry between April 1996 and November 1997. Of the 500 cases for whom psychiatric reports were retrieved, 220 (44%; 95% confidence interval 40% to 48%) had a lifetime history of mental disorder, while 71 (14%; 11% to 17%) had symptoms of mental illness at the time of the homicide. Of the total sample, 102 (14%; 12% to 17%) were confirmed to have been in contact with mental health services at some time, 58 (8%; 6% to 10%) in the year before the homicide. The commonest diagnosis was personality disorder (20 cases, 22%; 13% to 30%). Alcohol and drug misuse were also common. Only 15 subjects (18%; 10% to 26%) were receiving intensive community care, and 60 (63%; 53% to 73%) were out of contact at the time of the homicide. CONCLUSIONS: There are substantial rates of mental disorder in people convicted of homicide. Most do not have severe mental illness or a history of contact with mental health services. Inquiry findings suggest that preventing loss of contact with services and improving the clinical management of patients with both mental illness and substance misuse may reduce risk, but clinical trials are needed to examine the effectiveness of such interventions.

Psychological autopsy study of suicides by people aged under 35.

BACKGROUND: In the past two decades the suicide rate in young people has risen in the UK and other countries. AIMS: To identify the characteristics of people aged under 35 who commit suicide. METHOD: Psychological autopsy study with case-control design. Cases were 84 suicides and probable suicides (open verdicts). Controls were 64 age- and gender-matched non-suicides obtained through the general practices of the matched cases. MAIN VARIABLES: social, including employment status, marital status and living circumstances; life events and interpersonal difficulties; clinical, including current psychiatric disorder, alcohol and drug misuse, previous self-harm and personality disorder. RESULTS: A large number of highly significant social, interpersonal and clinical differences between suicides and controls was found. Factor analysis identified two groups of variables within each of the social, interpersonal and clinical domains which were independently linked to suicide, corresponding to: acute, severe mental disorder and chronic disorder of behaviour; rootlessness and social withdrawal; chronic and recent interpersonal problems. CONCLUSIONS: A broad prevention strategy is needed to reverse the recent rise in the suicide rate in young people.

Treatment with interferon-alpha preferentially reduces the capacity for amplification of granulocyte-macrophage progenitors (CFU-GM) from patients with chronic myeloid leukemia but spares normal CFU-GM.

The biological target for interferon (IFN)-alpha in chronic myeloid leukemia (CML) is unknown, but one possibility is that amplification of granulocyte-macrophage colony-forming cells (CFU-GM) is reduced. Replating CFU-GM colonies and observing secondary colony formation provides a measure of CFU-GM amplification. Amplification of CML, but not normal, CFU-GM in vitro was significantly inhibited by IFN-alpha (P = 0.02). In 5 out of 15 CML cases studied by fluorescence in situ hybridization, in vitro treatment with IFN-alpha increased the proportion of CFU-GM, which lacked BCR-ABL. The ability of patients' CFU-GM to amplify, and suppression of this ability by IFN-alpha, predicted responsiveness to IFN-alpha therapy in 86% of cases. Investigation of patients on treatment with IFN-alpha showed a threefold reduction in CFU-GM amplification in responders (P = 0.03) but no significant change in nonresponders (P = 0.8). We conclude that IFN-alpha preferentially suppresses amplification of CML CFU-GM to varying degrees. The differing in vitro sensitivities to IFN-alpha and growth kinetics of individual patients' cells could help differentiate those who will or will not benefit from treatment with IFN-alpha.