Pharmacokinetics of testosterone therapies in relation to diurnal variation of serum testosterone levels as men age.

BACKGROUND: To improve symptoms associated with testosterone deficiency, many testosterone therapies are available that aim to restore serum testosterone (T) levels to the normal physiologic range. The magnitude, frequency, and duration between peak and trough T concentrations vary with route of administration, and none reflect normal endogenous daily diurnal T variations. OBJECTIVE: To compare pharmacokinetic profiles of serum T from approved T formulations with endogenous diurnal T variations in young and older men, and to consider whether there may be value in mimicking the diurnal T rhythmicity with exogenous testosterone therapies as men age. MATERIALS AND METHODS: A literature search of studies examining the diurnal variation of endogenous T in healthy men and men with testosterone deficiency was performed using PubMed in January 2020. Additional searches for serum T pharmacokinetic profiles of various testosterone therapy formulations were also conducted. Prescribing information for various T formulations was also reviewed. DISCUSSION AND CONCLUSION: Endogenous diurnal T variation is well described and appears to be blunted naturally as men age. Men with testosterone deficiency lack diurnal T variation and exhibit a flatter T profile compared with eugonadal men. Some T replacement options provide intraday T level variations similar to normal circadian secretion, and others provide a flatter exposure profile reflective of depot release. Others provide profiles that exceed the frequency and physiologic range of the natural diurnal variation of T. All exogenous T replacement dosing targets an increase in average T levels to within the normal physiologic range and improves symptoms associated with low T, but no single testosterone therapy can exactly mimic the normal diurnal T patterns seen in younger men and the blunted circadian T secretion of older men.

Regulatory groundwater monitoring: Realistic residues of pinoxaden and metabolites at vulnerable locations.

A bespoke groundwater monitoring programme was designed to generate a database of pinoxaden and metabolite concentrations in shallow groundwater at agricultural locations across Europe. The data generated from this programme represent a higher tier refinement of modelled exposure estimates and provide realistic information on groundwater quality at vulnerable locations which will aid plant protection product (PPP) assessment in Europe in relation to Regulation (EC) No. 1107/2009. The Regulatory GeoPEARL_3.3.3 model developed by RIVM was used to estimate the vulnerability of cereal growing regions to leaching of two pinoxaden metabolites across the entire EU at a 1 km2 level using 20 years of daily weather data (MARS, EU JRC). Seventy sites located within the upper 50th percentile of leaching vulnerability from this modelling exercise, crop density and shallow groundwater were selected for monitoring groundwater. Retrospective and prospective pinoxaden product applications at candidate sites were recorded and these data used to place sites in the distribution for Europe. The 70 sites all fulfil the site assessment criteria and have no confining layers which may prevent or delay leaching. All sites equipped with groundwater wells had a minimum of two pinoxaden applications in the preceding four years to cereal crops. A total of 1326 samples were analysed from up to 90 down hydraulic gradient wells at 70 locations between June 2015 and July 2018. Results indicate that pinoxaden and pinoxaden metabolites are very unlikely to reach shallow groundwater at concentrations greater than 0.1 µg/L for relevant metabolites, or 10 µg/L for non-relevant metabolites, respectively (Sanco/221/2000-rev.10). Over 38 months of groundwater monitoring the annual average and 90th percentile for pinoxaden or its metabolites never exceeded 0.1 µg/L and it is proposed that these data infer that exposure to these metabolites is minimal.

Groundwater heat pump feasibility in shallow urban aquifers: Experience from Cardiff, UK.

Ground source heat pumps have the potential to decarbonise heating and cooling in many urban areas. The impact of using shallow groundwater from unconsolidated sedimentary aquifers for heating in urban areas is often modelled, but rarely validated from field measurements. This study presents findings from the 'Cardiff Urban Geo-Observatory' project. This study focuses on an experimental open loop ground source heat pump scheme retrofitted to a school building. Field monitoring for three years between 2015 and 2018 provided data on the environmental impact of the scheme on aquifer conditions. Average aquifer thermal degradation in the first three years was kept below 2 °C, with a maximum change of 4 °C measured during the heating season. The numerically modelled predictions of thermal degradation around the production and injection wells are compared with long-term field monitoring data, providing new insights into both aquifer, and user, behaviour. The Seasonal Performance Factor (SPFH4) of the pilot installation was 4.5 (W13/W50) in the monitoring period. An initial thermal resource estimation of the wider aquifer volume suggests that lowering the temperature of the aquifer by 8 °C could generate equivalent to 26% of the city's 2020 heating demand, but achievable heat extraction would in reality, be less. The study concludes that large parts of the aquifer can sustain shallow open loop ground source heat pump systems, as long as the local ground conditions support the required groundwater abstraction and re-injection rates. Future schemes can be de-risked and better managed by introduction of a registration of all GSHP schemes, with open sharing of investigation, design and performance monitoring data, and by managing thermal interference between systems using spatial planning tools.

The budget impact of using enteric-coated aspirin 325 mg + immediate-release omeprazole 40 mg to prevent recurrent cardiovascular events.

OBJECTIVE: Aspirin (acetylsalicylic acid; ASA) is commonly used for secondary prevention of cardiovascular (CV) events, but may be associated with gastrointestinal (GI) adverse events, which can reduce adherence. Use of ASA co-therapy with proton pump inhibitors in patients at risk may be suboptimal. PA32540 (Yosprala™) is a coordinated-delivery tablet combining EC-ASA 325 mg and immediate-release omeprazole 40 mg. The objective of this flexible budget impact model was to project the financial consequences of introducing PA32540 325 mg/40 mg to prevent recurrent CV events, while reducing ASA-associated GI events in US adults. METHODS: A Markov Model was employed to estimate health state transitions associated with ASA 75-325 mg, ASA 75-325 mg + generic delayed-release omeprazole 40 mg, PA32540, or clopidogrel 75 mg to prevent recurrent CV events. Health states included ulcers, GI bleeding, CV events, and death. Model inputs included demographics, treatment dosages, treatment costs, adverse GI and CV events, and premature death. Data from peer-reviewed literature and censuses enabled appropriate allocation of CV and GI disease prevalence and mortality. The PA32540 non-adherence rate was conservatively set at 20%. PA32540 market share was set to 50%. RESULTS: The model projected annual savings of $81.0 million to $190.9 million within 1-5 years after PA32540 introduction to the plan, which included 134,558 members at risk for recurrent CV events. These values translate into savings of $602 (year 5) to $1,419 (year 1) per patient per year, and $81 (year 5) to $191 (year 1) per member per year. These values were robust to variations in parameters under a deterministic sensitivity analysis. CONCLUSION: PA32540 use to prevent recurrent CV events was associated with cost reductions in each year examined with the model. From a health plan perspective, PA32540 is likely to have a net overall effect, resulting in significant cost savings.

Rapid Detection of Viable Bacillus anthracis Spores in Environmental Samples by Using Engineered Reporter Phages.

Bacillus anthracis, the causative agent of anthrax, was utilized as a bioterrorism agent in 2001 when spores were distributed via the U.S. postal system. In responding to this event, the Federal Bureau of Investigation used traditional bacterial culture viability assays to ascertain the extent of contamination of the postal facilities within 24 to 48 h of environmental sample acquisition. Here, we describe a low-complexity, second-generation reporter phage assay for the rapid detection of viableB. anthracis spores in environmental samples. The assay uses an engineered B. anthracis reporter phage (Wß::luxAB-2) which transduces bioluminescence to infected cells. To facilitate low-level environmental detection and maximize the signal response, expression of luxABin an earlier version of the reporter phage (Wß::luxAB-1) was optimized. These alterations prolonged signal kinetics, increased light output, and improved assay sensitivity. Using Wß::luxAB-2, detection of B. anthracis spores was 1 CFU in 8 h from pure cultures and as low as 10 CFU/g in sterile soil but increased to 10(5)CFU/g in unprocessed soil due to an unstable signal and the presence of competing bacteria. Inclusion of semiselective medium, mediated by a phage-expressed antibiotic resistance gene, maintained signal stability and enabled the detection of 10(4)CFU/g in 6 h. The assay does not require spore extraction and relies on the phage infecting germinating cells directly in the soil sample. This reporter phage displays promise for the rapid detection of low levels of spores on clean surfaces and also in grossly contaminated environmental samples from complex matrices such as soils.

Rapid Detection of Bacillus anthracis in Complex Food Matrices Using Phage-Mediated Bioluminescence.

Bacillus anthracis, the causative agent of anthrax, is considered a high-priority agent that may be used in a food-related terrorist attack because it can be contracted by ingestion and it also forms spores with heat and chemical resistance. Thus, novel surveillance methodologies to detect B. anthracis on adulterated foods are important for bioterrorism preparedness. We describe the development of a phage-based bioluminescence assay for the detection of B. anthracis on deliberately contaminated foods. We previously engineered the B. anthracis phage Wß with genes encoding bacterial luciferase (luxA and luxB) to create a "light-tagged" reporter (Wß::luxAB) that is able to rapidly detect B. anthracis by transducing a bioluminescent signal response. Here, we investigate the ability of Wß::luxAB to detect B. anthracis Sterne, an attenuated select agent strain, in inoculated food (ground beef) and milk (2%, baby formula, and half and half) matrices after incubation with spores for 72 h at 4°C as per AOAC testing guidelines. The majority of B. anthracis bacilli remained in spore form, and thus were potentially infectious, within each of the liquid matrices for 14 days. Detection limits were 80 CFU/ml after 7 h of enrichment; sensitivity of detection increased to 8 CFU/ml when enrichment was extended to 16 h. The limit of detection in ground beef was 3.2 × 10(3) CFU/g after 7 h of enrichment, improving to 3.2 × 10(2) CFU/g after 16 h. Because the time to result is rapid and minimal processing is required, and because gastrointestinal anthrax can be fatal, the reporter technology displays promise for the protection of our food supply following a deliberate release of this priority pathogen.

Bacillus anthracis diagnostic detection and rapid antibiotic susceptibility determination using 'bioluminescent' reporter phage.

Genetically modified phages have the potential to detect pathogenic bacteria from clinical, environmental, or food-related sources. Herein we assess an engineered 'bioluminescent' reporter phage (Wß::luxAB) as a clinical diagnostic tool for Bacillus anthracis, the etiological agent of anthrax. Wß::luxAB is able to rapidly (within minutes) detect a panel of B. anthracis strains by transducing a bioluminescent phenotype. The reporter phage displays species specificity by its inability, or significantly reduced ability, to detect members of the closely related Bacillus cereus group and other common bacterial pathogens. Using spiked clinical specimens, Wß::luxAB detects B. anthracis within 5 h at clinically relevant concentrations, and provides antibiotic susceptibility information that mirrors the CLSI method, except that data are obtained at least 5-fold faster. Although anthrax is a treatable disease, a positive patient prognosis is dependent on timely diagnosis and appropriate therapy. Wß::luxAB rapidly detects B. anthracis and determines antibiotic efficacy, properties that will help patient outcome.

"Light-tagged" bacteriophage as a diagnostic tool for the detection of phytopathogens.

Detection of the phytopathogen Pseudomonas cannabina pv alisalensis, the causal agent of bacterial blight of crucifers is essential for managing this disease. A phage-based diagnostic assay was developed that detects and identifies P. cannabina pv alisalensis from cultures and diseased plant specimens. A recombinant "light-tagged" reporter phage was generated by integrating the luxAB genes into the P. cannabina pv alisalensis phage PBSPCA1 genome. PBSPCA1::luxAB is viable, stable and detects P. cannabina pv alisalensis within minutes and with high sensitivity by conferring a bioluminescent signal. Detection is dependent on cell viability since cells treated with a bactericidal disinfectant are unable to elicit a signal. Importantly, the reporter phage detects P. cannabina pv alisalensis from diseased plant specimens indicating the potential of the diagnostic for disease identification. The reporter phage displays promise for the rapid and specific diagnostic detection of cultivated isolates, and infected plant specimens.

Enhanced enzymatic thermal stability and activity in functionalized mesoporous silica monitored by (31) p NMR.

Organophosphorus hydrolase (OPH) is immobilized on ammonium-modified mesoporous silica particles. Thermal stability and activity are measured with a (31) P NMR assay of the conversion of paraoxon (toxic) to its non-toxic hydrolysis product. After immobilization, OPH is significantly more active at room temperature and retained activity even after being heated to 45 °C for 1 month.

Phage-based platforms for the clinical detection of human bacterial pathogens.

Bacteriophages (phages) have been utilized for decades as a means for uniquely identifying their target bacteria. Due to their inherent natural specificity, ease of use, and straightforward production, phage possess a number of desirable attributes which makes them particularly suited as bacterial detectors. As a result, extensive research has been conducted into the development of phage, or phage-derived products to expedite the detection of human pathogens. However, very few phage-based diagnostics have transitioned from the research lab into a clinical diagnostic tool. Herein we review the phage-based platforms that are currently used for the detection of Mycobacterium tuberculosis, Yersinia pestis, Bacillus anthracis and Staphylococcus aureus in the clinical field. We briefly describe the disease, the current diagnostic options, and the role phage diagnostics play in identifying the cause of infection, and determining antibiotic susceptibility.

Rapid identification and antibiotic susceptibility testing of Yersinia pestis using bioluminescent reporter phage.

The rapid identification and antibiotic susceptibility testing of Yersinia pestis is paramount for a positive prognosis. We previously engineered a Y. pestis-specific 'bioluminescent' reporter phage for the identification of Y. pestis. In this study, we generated an improved reporter phage and evaluated the ability of this phage to provide direct and rapid susceptibility testing. Compared to the first generation reporter, the second generation reporter exhibited a 100-fold increase in signal strength, leading to a 10-fold increase in assay sensitivity. Y. pestis antimicrobial testing in the presence of the reporter elicited bioluminescent signals that were drug concentration-dependent, and produced susceptibility profiles that mirrored the standard CLSI method. The phage-generated susceptibility profiles, however, were obtained within hours in contrast to days with the conventional method.

Development of an engineered bioluminescent reporter phage for detection of bacterial blight of crucifers.

Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassicaceae family. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogen Pseudomonas syringae pv. maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant "light"-tagged reporter phage was generated by integrating bacterial luxAB genes encoding luciferase into the genome of P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage is viable and stable and retains properties similar to those of the wild-type phage. PBSPCA1::luxAB rapidly and sensitively detects P. cannabina pv. alisalensis by conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens of Brassica species such as P. syringae pv. maculicola, Pseudomonas marginalis, Pectobacterium carotovorum, Xanthomonas campestris pv. campestris, and X. campestris pv. raphani either do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detects P. cannabina pv. alisalensis on diseased plant specimens, indicating its potential for disease diagnosis.

Laser capture microdissection of Candida albicans from host tissue.

Laser microdissection is a technique in which specific populations of cells are acquired from sections of complex tissue under direct microscopic visualization. The technique can be used to selectively harvest or ablate host and/or fungal cells from a variety of biological specimens, including human, animal, or plant tissue sections. When coupled with downstream applications such as proteomic and molecular analyses, laser microdissection can address a variety of important biological questions specifically related to the in vivo host-fungus interaction. In this chapter, we describe how laser microdissection enables researchers to selectively isolate Candida albicans cells from host-infected tissue. Detailed protocols are provided for tissue handling and processing, slide preparation, and laser capture microdissection (LCM). Using these methods, we highlight the use of LCM to examine infection-related C. albicans gene expression.

'Bioluminescent' reporter phage for the detection of Category A bacterial pathogens.

Yersinia pestis and Bacillus anthracis are Category A bacterial pathogens that are the causative agents of the plague and anthrax, respectively. Although the natural occurrence of both diseases' is now relatively rare, the possibility of terrorist groups using these pathogens as a bioweapon is real. Because of the disease's inherent communicability, rapid clinical course, and high mortality rate, it is critical that an outbreak be detected quickly. Therefore methodologies that provide rapid detection and diagnosis are essential to ensure immediate implementation of public health measures and activation of crisis management. Recombinant reporter phage may provide a rapid and specific approach for the detection of Y. pestis and B. anthracis. The Centers for Disease Control and Prevention currently use the classical phage lysis assays for the confirmed identification of these bacterial pathogens. These assays take advantage of naturally occurring phage which are specific and lytic for their bacterial hosts. After overnight growth of the cultivated bacterium in the presence of the specific phage, the formation of plaques (bacterial lysis) provides a positive identification of the bacterial target. Although these assays are robust, they suffer from three shortcomings: 1) they are laboratory based; 2) they require bacterial isolation and cultivation from the suspected sample, and 3) they take 24-36 h to complete. To address these issues, recombinant "light-tagged" reporter phage were genetically engineered by integrating the Vibrio harveyi luxAB genes into the genome of Y. pestis and B. anthracis specific phage. The resulting luxAB reporter phage were able to detect their specific target by rapidly (within minutes) and sensitively conferring a bioluminescent phenotype to recipient cells. Importantly, detection was obtained either with cultivated recipient cells or with mock-infected clinical specimens. For demonstration purposes, here we describe the method for the phage-mediated detection of a known Y. pestis isolate using a luxAB reporter phage constructed from the CDC plague diagnostic phage ΦA1122 (Figure 1). A similar method, with minor modifications (e.g. change in growth temperature and media), may be used for the detection of B. anthracis isolates using the B. anthracis reporter phage Wß::luxAB. The method describes the phage-mediated transduction of a biolumescent phenotype to cultivated Y. pestis cells which are subsequently measured using a microplate luminometer. The major advantages of this method over the traditional phage lysis assays is the ease of use, the rapid results, and the ability to test multiple samples simultaneously in a 96-well microtiter plate format. Figure 1. Detection schematic. The phage are mixed with the sample, the phage infects the cell, luxAB are expressed, and the cell bioluminesces. Sample processing is not necessary; the phage and cells are mixed and subsequently measured for light.

Diagnostic bioluminescent phage for detection of Yersinia pestis.

Yersinia pestis is the etiological agent of the plague. Because of the disease's inherent communicability, rapid clinical course, and high mortality, it is critical that an outbreak, whether it is natural or deliberate, be detected and diagnosed quickly. The objective of this research was to generate a recombinant luxAB ("light")-tagged reporter phage that can detect Y. pestis by rapidly and specifically conferring a bioluminescent signal response to these cells. The bacterial luxAB reporter genes were integrated into a noncoding region of the CDC plague-diagnostic phage phiA1122 by homologous recombination. The identity and fitness of the recombinant phage were assessed through PCR analysis and lysis assays and functionally verified by the ability to transduce a bioluminescent signal to recipient cells. The reporter phage conferred a bioluminescent phenotype to Y. pestis within 12 min of infection at 28 degrees C. The signal response time and signal strength were dependent on the number of cells present. A positive signal was obtained from 10(2) cells within 60 min. A signal response was not detectable with Escherichia coli, although a weak signal (100-fold lower than that with Y. pestis) was obtained with 1 (of 10) Yersinia enterocolitica strains and 2 (of 10) Yersinia pseudotuberculosis strains at the restrictive temperature. Importantly, serum did not prevent the ability of the reporter phage to infect Y. pestis, nor did it significantly quench the resulting bioluminescent signal. Collectively, the results indicate that the reporter phage displays promise for the rapid and specific diagnostic detection of cultivated Y. pestis isolates or infected clinical specimens.

Susceptibility of gnotobiotic transgenic mice (Tgepsilon26) with combined deficiencies in natural killer cells and T cells to wild-type and hyphal signalling-defective mutants of Candida albicans.

Germfree transgenic epsilon 26 mice (Tgepsilon26), deficient in natural killer cells and T cells, were colonized (alimentary tract) with Candida albicans wild-type or each of two hyphal transcription factor signalling mutant strains (efg1/efg1, efg1/efg1 cph1/cph1). Each Candida strain colonized the alimentary tract, infected keratinized gastric tissues to a similar extent, and induced a granulocyte-dominated inflammatory response in infected tissues. Both wild-type and mutant strains formed hyphae in vivo and were able to elicit an increase in cytokine [tumour necrosis factor alpha, interleukin (IL)-10 and IL-12] and chemokine (KC and macrophage inflammatory protein-2] mRNAs in infected tissues; however, administration of the wild-type strain was lethal for the Tgepsilon26 mice, whereas the mice colonized with the mutant strains survived. Death of the Tgepsilon26-colonized mice appeared to be due to occlusive oesophageal candidiasis, and not to disseminated candidiasis of endogenous origin. In contrast, the mutant strains exhibited a significantly reduced capacity to infect (frequency and severity) oro-oesophageal (tongue and oesophagus) tissues. Therefore, the two hyphal signalling-defective mutants were less able to infect oro-oesophageal tissues and were non-lethal, but retained their ability to colonize the alimentary tract with yeast and hyphae, infect keratinized gastric tissues, and evoke an inflammatory response in orogastric tissues.

Candida glabrata and Candida albicans; dissimilar tissue tropism and infectivity in a gnotobiotic model of mucosal candidiasis.

Germ-free transgenic epsilon 26 (Tgepsilon26) mice, deficient in both natural killer (NK)- and T-cells, were inoculated (orally) with each of two Candida glabrata (BG2 or BG1003) or Candida albicans (CAF2-1 or SC5314) strains. Candida glabrata- or C. albicans-colonized mice exhibited similar numbers of viable Candida in the alimentary tract. Neither C. glabrata nor C. albicans caused systemic candidiasis of endogenous (alimentary tract) origin. Candida albicans invaded oroesophageal (tongue, palate, esophagus) and keratinized gastric tissues, evoked hyperkeratosis and a prominent, chronic, granulocyte-dominated, inflammatory response in all infected tissues, stimulated the production of splenic granulocytes and was lethal for the mice within 3-5 weeks after oral colonization. The two C. glabrata strains colonized the alimentary tract and penetrated into the keratinized (cardia-antrum) gastric tissues, but in contrast to C. albicans, were unable to infect oroesophageal tissues. Furthermore, C. glabrata strains were not lethal for the Tgepsilon26 mice, and did not evoke an inflammatory response in colonized gastric tissues or stimulate the production of splenic granulocytes. This 'stealth-like' behavior could explain the ability of C. glabrata to persist in infected tissues and survive as a commensal in the alimentary tract.

Development of a yeast biosensor-biocatalyst for the detection and biodegradation of the organophosphate paraoxon.

Organophosphate (OP) poisoning can occur through unintentional exposure to OP pesticides, or by the deliberate release of OP nerve agents. Consequently, there is considerable interest in the development of systems that can detect and/or biodegrade these agents. The aim of this study was to generate a prototype fluorescent reporter yeast biosensor that could detect and biodegrade the model OP pesticide, paraoxon, and subsequently detect paraoxon hydrolysis. Saccharomyces cerevisiae was engineered to hydrolyze paraoxon through the heterologous expression of the Flavobacterium species opd (organophosphate degrading) gene. Global transcription profiling was subsequently used to identify yeast genes, which were induced in the presence of paraoxon, and genes, which were associated with paraoxon hydrolysis. Paraoxon-inducible genes and genes associated with paraoxon hydrolysis were identified. Candidate paraoxon-inducible promoters were cloned and fused to the yeast-enhanced green fluorescent protein (yEGFP), and candidate promoters associated with paraoxon hydrolysis were fused to the red fluorescent protein (yDsRed). The ability of the yeast biosensor to detect paraoxon and paraoxon hydrolysis was demonstrated by the specific induction of the fluorescent reporter (yEGFP and yDsRed, respectively). Biosensors responded to paraoxon in a dose- and time-dependent manner, and detection was rapid (15 to 30 min). yDsRed induction occurred only in the recombinant opd(+) strains suggesting that yDsRed induction was strictly associated with paraoxon hydrolysis. Together, these results indicate that the yeast biocatalyst-biosensor can detect and degrade paraoxon and potentially also monitor the decontamination process.

The temporal dynamics of relationships between cannabis, psychosis and depression among young adults with psychotic disorders: findings from a 10-month prospective study.

BACKGROUND: The aim was to examine the temporal relationships over 10 months between cannabis use and symptoms of psychosis and depression in people with schizophrenia and related disorders. The design was a prospective study of 101 patients with schizophrenia and related disorders who were assessed monthly over 10 months on medication compliance, cannabis and other drug use, symptoms of depression and symptoms of psychosis. METHOD: Linear regression methods to assess relationships between cannabis use and symptoms of psychosis and depression while adjusting for serial dependence, medication compliance and other demographic and clinical variables. RESULTS: Cannabis use predicted a small but statistically significant increase in symptoms of psychosis, but not depression, after controlling for other differences between cannabis users and non-users. Symptoms of depression and psychosis did not predict cannabis use. CONCLUSION: Continued cannabis use by persons with schizophrenia predicts a small increase in psychotic symptom severity but not vice versa.

Reasons for cannabis use in psychosis.

OBJECTIVE: To examine the reasons for cannabis use among individuals with psychotic disorders. METHOD: Forty-nine people with psychotic disorders in treatment with community health centres in Northern Sydney were interviewed to collect information about their experience of antipsychotic side-effects and their influence on cannabis use. Other information collected on cannabis use included: amount and frequency, effects of use and other general reasons given for use. RESULTS: It was found that boredom, social motives, improving sleep, anxiety and agitation and symptoms associated with negative psychotic symptoms or depression were the most important motivators of cannabis use. Positive symptoms of psychosis and antipsychotic side-effects that were not associated with anxiety, were not important motivators of cannabis use. CONCLUSIONS: As cannabis use may precipitate relapse in this population, it is important to reduce these motivators of use. Clinician's must assess and treat these problems, thus reducing the need for patients to self-medicate with cannabis, and therefore reducing the risk of relapse.