1
|
Mersiades AJ, Tognela A, Haber PS, Stockler M, Lintzeris N, Simes J, McGregor I, Olver I, Allsop DJ, Gedye C, Kirby AC, Morton RL, Fox P, Clarke S, Briscoe K, Aghmesheh M, Wong N, Walsh A, Hahn C, Grimison P. Oral cannabinoid-rich THC/CBD cannabis extract for secondary prevention of chemotherapy-induced nausea and vomiting: a study protocol for a pilot and definitive randomised double-blind placebo-controlled trial (CannabisCINV). BMJ Open 2018; 8:e020745. [PMID: 30209152 PMCID: PMC6144412 DOI: 10.1136/bmjopen-2017-020745] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 06/07/2018] [Accepted: 06/21/2018] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Chemotherapy-induced nausea and vomiting (CINV) remains an important issue for patients receiving chemotherapy despite guideline-consistent antiemetic therapy. Trials using delta-9-tetrahydrocannabinol-rich (THC) products demonstrate limited antiemetic effect, significant adverse events and flawed study design. Trials using cannabidiol-rich (CBD) products demonstrate improved efficacy and psychological adverse event profile. No definitive trials have been conducted to support the use of cannabinoids for this indication, nor has the potential economic impact of incorporating such regimens into the Australian healthcare system been established. CannabisCINV aims to assess the efficacy, safety and cost-effectiveness of adding TN-TC11M, an oral THC/CBD extract to guideline-consistent antiemetics in the secondary prevention of CINV. METHODS AND ANALYSIS The current multicentre, 1:1 randomised cross-over, placebo-controlled pilot study will recruit 80 adult patients with any malignancy, experiencing CINV during moderate to highly emetogenic chemotherapy despite guideline-consistent antiemetics. Patients receive oral TN-TC11M (THC 2.5mg/CBD 2.5 mg) capsules or placebo capsules three times a day on day -1 to day 5 of cycle A of chemotherapy, followed by the alternative drug regimen during cycle B of chemotherapy and the preferred drug regimen during cycle C. The primary endpoint is the proportion of subjects attaining a complete response to CINV. Secondary and tertiary endpoints include regimen tolerability, impact on quality of life and health system resource use. The primary assessment tool is patient diaries, which are filled from day -1 to day 5. A subsequent randomised placebo-controlled parallel phase III trial will recruit a further 250 patients. ETHICS AND DISSEMINATION The protocol was approved by ethics review committees for all participating sites. Results will be disseminated in peer-reviewed journals and at scientific conferences. DRUG SUPPLY Tilray. PROTOCOL VERSION 2.0, 9 June 2017. TRIAL REGISTRATION NUMBER ANZCTR12616001036404; Pre-results.
Collapse
Affiliation(s)
- Antony J Mersiades
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Annette Tognela
- Macarthur Cancer Therapy Centre, Campbelltown Hospital, Sydney, New South Wales, Australia
| | - Paul S Haber
- Discipline of Addiction Medicine, University of Sydney, Sydney, New South Wales, Australia
- Drug Health Services, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Martin Stockler
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
- Department of Medical Oncology, Concord Cancer Care Centre, Concord Hospital, Sydney, New South Wales, Australia
| | - Nicholas Lintzeris
- Discipline of Addiction Medicine, University of Sydney, Sydney, New South Wales, Australia
- Drug and Alcohol Services, South East Sydney Local Health District, Sydney, New South Wales, Australia
| | - John Simes
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
- Department of Medical Oncology, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia
| | - Iain McGregor
- Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Sydney, New South Wales, Australia
| | - Ian Olver
- University of South Australia Cancer Research Institute, University of South Australia, Adelaide, South Australia, Australia
| | - David J Allsop
- Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Sydney, New South Wales, Australia
| | - Craig Gedye
- Department of Medical Oncology, Calvary Mater Newcastle, Newcastle, New South Wales, Australia
| | - Adrienne C Kirby
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Rachael L Morton
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Peter Fox
- Central West Cancer Care Centre, Orange Health Service, Orange, New South Wales, Australia
| | - Stephen Clarke
- Department of Medical Oncology, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Bill Walsh Cancer Research Laboratory, Kolling Institute of Medical Research, Sydney, New South Wales, Australia
| | - Karen Briscoe
- Mid North Coast Cancer Institute, Coffs Harbour Hospital, Coffs Harbour, New South Wales, Australia
| | - Morteza Aghmesheh
- Illawarra Shoalhaven Cancer and Haematology Network, Wollongong Hospital, Wollongong, New South Wales, Australia
| | - Nicole Wong
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Anna Walsh
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Carmel Hahn
- Department of Medical Oncology, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia
| | - Peter Grimison
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
- Department of Medical Oncology, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia
| |
Collapse
|
2
|
Lintzeris N, Driels J, Elias N, Arnold JC, McGregor IS, Allsop DJ. Medicinal cannabis in Australia, 2016: the Cannabis as Medicine Survey (CAMS-16). Med J Aust 2018; 209:211-216. [PMID: 30092752 DOI: 10.5694/mja17.01247] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/01/2018] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To explore patterns of cannabis use for medical purposes in Australia immediately prior to the 2016 legislation for frameworks for medical cannabis use. Design, setting: Anonymous online survey with convenience sample, April-October 2016. Participants were recruited through online media and at professional and consumer forums. PARTICIPANTS Adults (at least 18 years of age) who reported using a cannabis product for self-identified medical or therapeutic reasons during the preceding 12 months. MAIN OUTCOME MEASURES Consumer characteristics; indications and patterns of medical cannabis use; perceived benefits and harms; views on appropriate availability of medical cannabis. RESULTS Most of the 1748 participants were men (68.1%) and employed (56.6%), with a mean age of 37.9 years (SD, 13.4 years) and mean reported period of medical cannabis use of 9.8 years (SD, 12.5 years). The most frequent reasons for medical cannabis use were anxiety (50.7%), back pain (50.0%), depression (49.3%), and sleep problems (43.5%). Respondents had used medical cannabis on a mean of 19.9 of the previous 28 days (SD, 10.0 days), spending a mean $68.60 (SD, $85.00) per week, and 83.4% had inhaled the substance. Participants reported high levels of clinical effectiveness and frequent side effects, including drowsiness, ocular irritation, lethargy and memory impairment; 17% met DSM-5 criteria for moderate or severe cannabis use disorder. Many reported harms or concerns related to the illicit status of cannabis. Participants believed that medical cannabis should be integrated into mainstream health care, and that products should be required to meet consistency and safety standards. CONCLUSION Illicitly sourced cannabis is used to treat a broad range of medical conditions in Australia. Future models of prescribed medical cannabis take consumer patterns of use and demand into consideration.
Collapse
Affiliation(s)
| | | | - Natalie Elias
- Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Sydney, NSW
| | | | | | - David J Allsop
- Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Sydney, NSW
| |
Collapse
|
3
|
Suraev A, Lintzeris N, Stuart J, Kevin RC, Blackburn R, Richards E, Arnold JC, Ireland C, Todd L, Allsop DJ, McGregor IS. Composition and Use of Cannabis Extracts for Childhood Epilepsy in the Australian Community. Sci Rep 2018; 8:10154. [PMID: 29977078 PMCID: PMC6033872 DOI: 10.1038/s41598-018-28127-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 06/04/2018] [Indexed: 12/20/2022] Open
Abstract
Recent surveys suggest that many parents are using illicit cannabis extracts in the hope of managing seizures in their children with epilepsy. In the current Australian study we conducted semi-structured interviews with families of children with diverse forms of epilepsy to explore their attitudes towards and experiences with using cannabis extracts. This included current or previous users of cannabis extracts to treat their child's seizures (n = 41 families), and families who had never used (n = 24 families). For those using cannabis, extracts were analysed for cannabinoid content, with specific comparison of samples rated by families as "effective" versus those rated "ineffective". Results showed that children given cannabis extracts tended to have more severe epilepsy historically and had trialled more anticonvulsants than those who had never received cannabis extracts. There was high variability in the cannabinoid content and profile of cannabis extracts rated as "effective", with no clear differences between extracts perceived as "effective" and "ineffective". Contrary to family's expectations, most samples contained low concentrations of cannabidiol, while Δ9-tetrahydrocannabinol was present in nearly every sample. These findings highlight profound variation in the illicit cannabis extracts being currently used in Australia and warrant further investigations into the therapeutic value of cannabinoids in epilepsy.
Collapse
Affiliation(s)
- A Suraev
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - N Lintzeris
- Addiction Medicine, Central Clinical School, Faculty of Medicine, The University of Sydney, Sydney, 2006, Australia
- The Langton Centre, Drug and Alcohol Services, South East Sydney Local Health District, NSW Health, Surry Hills, 2010, Australia
| | - J Stuart
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - R C Kevin
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - R Blackburn
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - E Richards
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - J C Arnold
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
- Department of Pharmacology, Faculty of Medicine, University of Sydney, Sydney, NSW, 2006, Australia
| | - C Ireland
- Epilepsy Action Australia, Sydney, Australia
| | - L Todd
- Epilepsy Action Australia, Sydney, Australia
| | - D J Allsop
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia
| | - I S McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, The University of Sydney, Sydney, 2050, Australia.
| |
Collapse
|
4
|
Mersiades A, Tognela A, Haber P, Stockler MR, Lintzeris N, McGregor I, Olver I, Allsop DJ, Gedye C, Kirby A, Morton RL, Tran AT, Briscoe KP, Fox P, Clarke SJ, Aghmesheh M, Wong N, Walsh A, Hahn C, Grimison PS. Pilot and definitive randomised double-blind placebo-controlled trials evaluating an oral cannabinoid-rich THC/CBD cannabis extract for secondary prevention of chemotherapy-induced nausea and vomiting (CINV). J Clin Oncol 2018. [DOI: 10.1200/jco.2018.36.15_suppl.tps10128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Antony Mersiades
- NHMRC Clinical Trials Centre, The University of Sydney, Sydney, Australia
| | - Annette Tognela
- Macarthur Cancer Therapy Centre, South Western Sydney Local Health District, Campbelltown, Australia
| | - Paul Haber
- Sydney Medical School, University of Sydney, Camperdown, Australia
| | - Martin R. Stockler
- NHMRC Clinical Trials Centre, The University of Sydney, Sydney, Australia
| | - Nicholas Lintzeris
- Drug and Alcohol Services, South East Sydney Local Health District, Concord, Australia
| | - Iain McGregor
- Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, Camperdown, Australia
| | - Ian Olver
- Sansom Institute for Health Research, University of South Australia, Adelaide, Australia
| | - David J Allsop
- Sydney Medical School, University of Sydney, Camperdown, Australia
| | - Craig Gedye
- Calvary Mater Newcastle, Newcastle, Australia
| | - Adrienne Kirby
- NHMRC Clinical Trials Centre, The University of Sydney, Sydney, Australia
| | - Rachael L Morton
- NHMRC Clinical Trials Centre, The University of Sydney, Sydney, Australia
| | - Anh T Tran
- NHMRC Clinical Trials Centre, The University of Sydney, Sydney, Australia
| | - Karen P. Briscoe
- Mid North Coast Cancer Institute, Mid North Coast Local Health District, Coffs Harbour, Australia
| | - Peter Fox
- Central West Cancer Services, Orange, Australia
| | | | - Morteza Aghmesheh
- Illawarra Cancer Care Centre, Illawarra Shoalhaven Local Health District, Wollongong, Australia
| | - Nicole Wong
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Anna Walsh
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | | | | |
Collapse
|
5
|
Bhardwaj AK, Allsop DJ, Copeland J, McGregor IS, Dunlop A, Shanahan M, Bruno R, Phung N, Montebello M, Sadler C, Gugusheff J, Jackson M, Luksza J, Lintzeris N. Randomised Controlled Trial (RCT) of cannabinoid replacement therapy (Nabiximols) for the management of treatment-resistant cannabis dependent patients: a study protocol. BMC Psychiatry 2018; 18:140. [PMID: 29776349 PMCID: PMC5960200 DOI: 10.1186/s12888-018-1682-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 03/28/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The cannabis extract nabiximols (Sativex®) effectively supresses withdrawal symptoms and cravings in treatment resistant cannabis dependent individuals, who have high relapse rates following conventional withdrawal treatments. This study examines the efficacy, safety and cost-effectiveness of longer-term nabiximols treatment for outpatient cannabis dependent patients who have not responded to previous conventional treatment approaches. METHODS/DESIGN A phase III multi-site outpatient, randomised, double-blinded, placebo controlled parallel design, comparing a 12-week course of nabiximols to placebo, with follow up at 24 weeks after enrolment. Four specialist drug and alcohol outpatient clinics in New South Wales, Australia. One hundred forty-two treatment seeking cannabis dependent adults, with no significant medical, psychiatric or other substance use disorders. Nabiximols is an oromucosal spray prescribed on a flexible dose regimen to a maximum daily dose of 32 sprays; 8 sprays (total 21.6 mg tetrahydrocannabinol (THC) and 20 mg cannabidiol (CBD)) four times a day, or matching placebo, dispensed weekly. All participants will receive six-sessions of individual cognitive behavioural therapy (CBT) and weekly clinical reviews. Primary endpoints are use of non-prescribed cannabis (self-reported cannabis use days, urine toxicology), safety measures (adverse events and abuse liability), and cost effectiveness (incremental cost effectiveness in achieving additional Quality Adjusted Life Years). Secondary outcomes include, improvement in physical and mental health parameters, substance use other than cannabis, cognitive functioning and patient satisfaction measures. DISCUSSION This is the first outpatient community-based randomised controlled study of nabiximols as an agonist replacement medication for treating cannabis dependence, targeting individuals who have not previously responded to conventional treatment approaches. The study and treatment design is modelled upon an earlier study with this population and more generally on other agonist replacement treatments (e.g. nicotine, opioids). TRIAL REGISTRATION Australian and New Zealand Clinical Trial Registry: ACTRN12616000103460 (Registered 1st February 2016).
Collapse
Affiliation(s)
- Anjali K. Bhardwaj
- Discipline of Addiction Medicine, Central Clinical School, University of Sydney, Sydney, NSW Australia
- The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Sydney, NSW Australia
- School of Psychology, University of Sydney, Sydney, NSW Australia
| | - David J. Allsop
- School of Psychology, University of Sydney, Sydney, NSW Australia
| | - Jan Copeland
- National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW Australia
| | - Iain S. McGregor
- School of Psychology, University of Sydney, Sydney, NSW Australia
| | - Adrian Dunlop
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, Newcastle, NSW Australia
| | - Marian Shanahan
- National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW Australia
| | - Raimondo Bruno
- National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW Australia
- School of Medicine, University of Tasmania, Hobart, TAS Australia
| | - Nghi Phung
- Centre for Addiction Medicine, Cumberland Hospital, Western Sydney Local Health District, Sydney, NSW Australia
| | - Mark Montebello
- The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Sydney, NSW Australia
| | - Craig Sadler
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, Newcastle, NSW Australia
| | - Jessica Gugusheff
- Discipline of Addiction Medicine, Central Clinical School, University of Sydney, Sydney, NSW Australia
- The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Sydney, NSW Australia
| | - Melissa Jackson
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, Newcastle, NSW Australia
| | - Jennifer Luksza
- Centre for Addiction Medicine, Cumberland Hospital, Western Sydney Local Health District, Sydney, NSW Australia
| | - Nicholas Lintzeris
- Discipline of Addiction Medicine, Central Clinical School, University of Sydney, Sydney, NSW Australia
- The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Sydney, NSW Australia
| |
Collapse
|
6
|
Lovell ME, Bruno R, Johnston J, Matthews A, McGregor I, Allsop DJ, Lintzeris N. Cognitive, physical, and mental health outcomes between long-term cannabis and tobacco users. Addict Behav 2018; 79:178-188. [PMID: 29291509 DOI: 10.1016/j.addbeh.2017.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/17/2017] [Accepted: 12/07/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Cannabis intoxication adversely affects health, yet persistent effects following short-term abstinence in long-term cannabis users are unclear. This matched-subjects, cross-sectional study compared health outcomes of long-term cannabis and long-term tobacco-only users, relative to population norms. METHODS Nineteen long-term (mean 32.3years of use, mean age 55.7years), abstinent (mean 15h) cannabis users and 16 long-term tobacco users (mean 37.1years of use, mean age 52.9years), matched for age, educational attainment, and lifetime tobacco consumption, were compared on measures of learning and memory, response inhibition, information-processing, sustained attention, executive control, and mental and physical health. RESULTS Cannabis users exhibited poorer overall learning and delayed recall and greater interference and forgetting than tobacco users, and exhibited poorer recall than norms. Inhibition and executive control were similar between groups, but cannabis users had slower reaction times during information processing and sustained attention tasks. Cannabis users had superior health satisfaction and psychological, somatic, and general health than tobacco users and had similar mental and physical health to norms whilst tobacco users had greater stress, role limitations from emotional problems, and poorer health satisfaction. CONCLUSIONS Long-term cannabis users may exhibit deficits in some cognitive domains despite short-term abstinence and may therefore benefit from interventions to improve cognitive performance. Tobacco alone may contribute to adverse mental and physical health outcomes, which requires appropriate control in future studies.
Collapse
Affiliation(s)
- M E Lovell
- School of Medicine (Psychology), University of Tasmania, Hobart, Tasmania 7000, Australia.
| | - R Bruno
- School of Medicine (Psychology), University of Tasmania, Hobart, Tasmania 7000, Australia
| | - J Johnston
- University Centre for Rural Health - North Coast, University of Sydney, Lismore, New South Wales 2480, Australia
| | - A Matthews
- School of Medicine (Psychology), University of Tasmania, Hobart, Tasmania 7000, Australia
| | - I McGregor
- Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, Brain and Mind Centre, University of Sydney, New South Wales 2006, Australia
| | - D J Allsop
- Lambert Initiative for Cannabinoid Therapeutics, School of Psychology, Brain and Mind Centre, University of Sydney, New South Wales 2006, Australia
| | - N Lintzeris
- Discipline of Addictive Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia; The Langton Centre, South East Sydney Local Health District (SESLHD), Drug and Alcohol Services, 2010, Australia
| |
Collapse
|
7
|
Suraev AS, Todd L, Bowen MT, Allsop DJ, McGregor IS, Ireland C, Lintzeris N. An Australian nationwide survey on medicinal cannabis use for epilepsy: History of antiepileptic drug treatment predicts medicinal cannabis use. Epilepsy Behav 2017; 70:334-340. [PMID: 28238865 DOI: 10.1016/j.yebeh.2017.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 11/30/2022]
Abstract
Epilepsy Action Australia conducted an Australian nationwide online survey seeking opinions on and experiences with the use of cannabis-based products for the treatment of epilepsy. The survey was promoted via the Epilepsy Action Australia's main website, on their Facebook page, and by word of mouth. The survey consisted of 39 questions assessing demographics, clinical factors, including diagnosis and seizure types, and experiences with and opinions towards cannabis use in epilepsy. A total of 976 responses met the inclusion criteria. Results show that 15% of adults with epilepsy and 13% of parents/guardians of children with epilepsy were currently using, or had previously used, cannabis products to treat epilepsy. Of those with a history of cannabis product use, 90% of adults and 71% of parents reported success in reducing seizure frequency after commencing cannabis products. The main reasons for medicinal cannabis use were to manage treatment-resistant epilepsy and to obtain a more favorable side-effect profile compared to standard antiepileptic drugs. The number of past antiepileptic drugs tried was a significant predictor of medicinal cannabis use in both adults and children with epilepsy. Fifty-six percent of adults with epilepsy and 62% of parents/guardians of children with epilepsy expressed willingness to participate in clinical trials of cannabinoids. This survey provides insight into the use of cannabis products for epilepsy, in particular some of the likely factors influencing use, as well as novel insights into the experiences of and attitudes towards medicinal cannabis in people with epilepsy in the Australian community. This article is part of a Special Issue entitled "Cannabinoids and Epilepsy".
Collapse
Affiliation(s)
- Anastasia S Suraev
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, Australia.
| | - Lisa Todd
- Epilepsy Action Australia, Sydney, Australia
| | - Michael T Bowen
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, Australia
| | - David J Allsop
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, Australia
| | - Iain S McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, Australia
| | | | - Nicholas Lintzeris
- Drug and Alcohol Services, South Eastern Sydney Local Health District New South Wales Ministry of Health, Sydney, Australia; Addiction Medicine, Central Clinical School, Faculty of Medicine, The University of Sydney, Sydney, Australia
| |
Collapse
|
8
|
|
9
|
Allsop DJ, Bartlett DJ, Johnston J, Helliwell D, Winstock A, McGregor IS, Lintzeris N. The Effects of Lithium Carbonate Supplemented with Nitrazepam on Sleep Disturbance during Cannabis Abstinence. J Clin Sleep Med 2015; 11:1153-62. [PMID: 26285109 DOI: 10.5664/jcsm.5090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/30/2015] [Indexed: 01/08/2023]
Abstract
STUDY OBJECTIVE Sleep disturbance is a hallmark feature of cannabis withdrawal. In this study we explored the effects of lithium treatment supplemented with nitrazepam on objective and subjective measures of sleep quality during inpatient cannabis withdrawal. METHODS Treatment-seeking cannabis-dependent adults (n = 38) were admitted for 8 days to an inpatient withdrawal unit and randomized to either oral lithium (500 mg) or placebo, twice daily in a double-blind RCT. Restricted nitrazepam (10 mg) was available on demand (in response to poor sleep) on any 3 of the 7 nights. Dependent outcome measures for analysis included repeated daily objective actigraphy and subjective sleep measures throughout the 8 day detox, subjective cannabis withdrawal ratings, and detoxification completion rates. RESULTS Based on actigraphy, lithium resulted in less fragmented sleep compared to placebo (p = 0.04), but no other objective measures were improved by lithium. Of the subjective measures, only nightmares were suppressed by lithium (p = 0.04). Lithium did not have a significant impact on the use of nitrazepam. Sleep bout length (p < 0.0001), sleep efficiency (p < 0.0001), and sleep fragmentation (p = 0.05) were improved on nights in which nitrazepam was used. In contrast, only night sweats improved with nitrazepam from the subjective measures (p = 0.04). A Cox regression with daily repeated measures of sleep efficiency averaged across all people in the study a predictor suggests that a one-unit increase in sleep efficiency (the ratio of total sleep time to the total time in bed expressed as a percentage) resulted in a 14.6% increase in retention in treatment (p = 0.008, Exp(B) = 0.854, 95% CI = 0.759-0.960). None of the other sleep measures, nor use of lithium or nitrazepam were significantly associated with retention in treatment. CONCLUSIONS Lithium seems to have only limited efficacy on sleep disturbance in cannabis withdrawal. However the nitrazepam improved several actigraphy measures of sleep disturbance, warranting further investigation. Discord between objective and subjective sleep indices suggest caution in evaluating treatment interventions with self-report sleep data only.
Collapse
Affiliation(s)
- David J Allsop
- School of Psychology, University of Sydney, Sydney, NSW, Australia.,Discipline of Addiction Medicine, Central Clinical School, University of Sydney, NSW Australia.,The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Surry Hills, NSW, Australia
| | - Delwyn J Bartlett
- Woolcock Institute of Medical Research &University of Sydney, NSW, Australia
| | - Jennifer Johnston
- University Centre for Rural Health, University of Sydney, Lismore, NSW, Australia
| | | | | | - Iain S McGregor
- School of Psychology, University of Sydney, Sydney, NSW, Australia
| | - Nicholas Lintzeris
- Discipline of Addiction Medicine, Central Clinical School, University of Sydney, NSW Australia.,The Langton Centre, Drug and Alcohol Services, South Eastern Sydney Local Health District, Surry Hills, NSW, Australia
| |
Collapse
|
10
|
Allsop DJ, Lintzeris N, Copeland J, Dunlop A, McGregor IS. Cannabinoid replacement therapy (CRT): Nabiximols (Sativex) as a novel treatment for cannabis withdrawal. Clin Pharmacol Ther 2015; 97:571-4. [DOI: 10.1002/cpt.109] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/05/2015] [Indexed: 11/08/2022]
Affiliation(s)
- DJ Allsop
- Psychopharmacology Laboratory; School of Psychology, Faculty of Science, University of Sydney; NSW Australia
- Discipline of Addiction Medicine, Faculty of Medicine; University of Sydney; NSW Australia
| | - N Lintzeris
- Discipline of Addiction Medicine, Faculty of Medicine; University of Sydney; NSW Australia
- Drug and Alcohol Services, South East Sydney Local Health District, New South Wales Health; NSW Australia
| | - J Copeland
- National Cannabis Prevention and Information Centre; UNSW Medicine; Australia
| | - A Dunlop
- Drug & Alcohol Clinical Services; Hunter New England Local Health District, New South Wales Ministry of Health; Australia
- School of Medicine and Public Health, Faculty of Health, University of Newcastle; Australia
| | - IS McGregor
- Psychopharmacology Laboratory; School of Psychology, Faculty of Science, University of Sydney; NSW Australia
| |
Collapse
|
11
|
Johnston J, Lintzeris N, Allsop DJ, Suraev A, Booth J, Carson DS, Helliwell D, Winstock A, McGregor IS. Lithium carbonate in the management of cannabis withdrawal: a randomized placebo-controlled trial in an inpatient setting. Psychopharmacology (Berl) 2014; 231:4623-36. [PMID: 24880749 DOI: 10.1007/s00213-014-3611-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 04/28/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Preclinical studies suggest that lithium carbonate (lithium) can reduce precipitated cannabinoid withdrawal in rats by stimulating release of the neuropeptide oxytocin, while two open-label studies indicate lithium may ameliorate cannabis withdrawal symptoms in humans. OBJECTIVES This study was conducted to examine the efficacy and safety of lithium in the inpatient management of cannabis withdrawal and to determine whether lithium affects plasma oxytocin and the rate of elimination of plasma cannabinoids during abstinence. METHODS Treatment-seeking cannabis-dependent adults (n = 38) were admitted for 8 days to an inpatient withdrawal unit and randomized to either oral lithium (500 mg) or placebo given twice a day under double-blind randomized controlled trial (RCT) conditions. Primary outcomes included withdrawal severity [cannabis withdrawal scale (CWS)], rates of detoxification completion, and adverse events. Plasma cannabinoids, plasma oxytocin and serum lithium levels were measured repeatedly over admission. Follow-up research interviews were conducted at 14, 30, and 90 days postdischarge. RESULTS Lithium did not significantly affect total CWS scores relative to placebo, although it significantly reduced individual symptoms of "loss of appetite," "stomach aches," and "nightmares/strange dreams." No significant group differences were found in treatment retention or adverse events. Lithium did not increase plasma oxytocin levels nor influence the rate of elimination of cannabinoids. Both placebo- and lithium-treated participants showed reduced levels of cannabis use (verified by urinalysis) and improved health and psychosocial outcomes at 30- and 90-day follow-up relative to pretreatment baselines. CONCLUSIONS Despite the strong rationale for the present study, the efficacy of lithium over placebo in the management of cannabis withdrawal was not demonstrated.
Collapse
Affiliation(s)
- Jennifer Johnston
- Discipline of Addiction Medicine, University of Sydney, Camperdown, NSW, 2050, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Wong A, Keats K, Rooney K, Hicks C, Allsop DJ, Arnold JC, McGregor IS. Fasting and exercise increase plasma cannabinoid levels in THC pre-treated rats: an examination of behavioural consequences. Psychopharmacology (Berl) 2014; 231:3987-96. [PMID: 24696079 DOI: 10.1007/s00213-014-3532-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/04/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Δ(9)-Tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, accumulates in fat tissue where it can remain for prolonged periods. Under conditions of increased fat utilisation, blood cannabinoid concentrations can increase. However, it is unclear whether this has behavioural consequences. OBJECTIVES Here, we examined whether rats pre-treated with multiple or single doses of THC followed by a washout would show elevated plasma cannabinoids and altered behaviour following fasting or exercise manipulations designed to increase fat utilisation. METHODS Behavioural impairment was measured as an inhibition of spontaneous locomotor activity or a failure to successfully complete a treadmill exercise session. Fat utilisation was indexed by plasma free fatty acid (FFA) levels with plasma concentrations of THC and its terminal metabolite (-)-11-nor-9-carboxy-∆(9)-tetrahydrocannabinol (THC-COOH) also measured. RESULTS Rats given daily THC (10 mg/kg) for 5 days followed by a 4-day washout showed elevated plasma THC-COOH when fasted for 24 h relative to non-fasted controls. Fasted rats showed lower locomotor activity than controls suggesting a behavioural effect of fat-released THC. However, rats fasted for 20 h after a single 5-mg/kg THC injection did not show locomotor suppression, despite modestly elevated plasma THC-COOH. Rats pre-treated with THC (5 mg/kg) and exercised 20 h later also showed elevated plasma THC-COOH but did not differ from controls in their likelihood of completing 30 min of treadmill exercise. CONCLUSIONS These results confirm that fasting and exercise can increase plasma cannabinoid levels. Behavioural consequences are more clearly observed with pre-treatment regimes involving repeated rather than single THC dosing.
Collapse
Affiliation(s)
- Alexander Wong
- The Discipline of Pharmacology, The University of Sydney, Darlington, NSW, 2006, Australia
| | | | | | | | | | | | | |
Collapse
|
13
|
Allsop DJ, Copeland J, Lintzeris N, Dunlop AJ, Montebello M, Sadler C, Rivas GR, Holland RM, Muhleisen P, Norberg MM, Booth J, McGregor IS. Nabiximols as an agonist replacement therapy during cannabis withdrawal: a randomized clinical trial. JAMA Psychiatry 2014; 71:281-91. [PMID: 24430917 DOI: 10.1001/jamapsychiatry.2013.3947] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE There are no medications approved for treating cannabis dependence or withdrawal. The cannabis extract nabiximols (Sativex), developed as a multiple sclerosis treatment, offers a potential agonist medication for cannabis withdrawal. OBJECTIVE To evaluate the safety and efficacy of nabiximols in treating cannabis withdrawal. DESIGN, SETTING, AND PARTICIPANTS A 2-site, double-blind randomized clinical inpatient trial with a 28-day follow-up was conducted in New South Wales, Australia. Participants included 51 DSM-IV-TR cannabis-dependent treatment seekers. INTERVENTIONS A 6-day regimen of nabiximols (maximum daily dose, 86.4 mg of Δ9-tetrahydrocannabinol and 80 mg of cannabidiol) or placebo with standardized psychosocial interventions during a 9-day admission. MAIN OUTCOMES AND MEASURES Severity of cannabis withdrawal and cravings (Cannabis Withdrawal Scale), retention in withdrawal treatment, and adverse events. Secondary outcomes include postwithdrawal cannabis use, health outcomes, and psychosocial outcomes. RESULTS Nabiximols treatment significantly reduced the overall severity of cannabis withdrawal relative to placebo (F8,377.97 = 2.39; P = .01), including effects on withdrawal-related irritability, depression, and cannabis cravings. Nabiximols had a more limited, but still positive, therapeutic benefit on sleep disturbance, anxiety, appetite loss, physical symptoms, and restlessness. Nabiximols patients remained in treatment longer during medication use (unadjusted hazard ratio, 3.66 [95% CI, 1.18-11.37]; P = .02), with 2.84 the number needed to treat to achieve successful retention in treatment. Participants could not reliably differentiate between nabiximols and placebo treatment (χ21 = 0.79; P = .67), and those receiving nabiximols did not report greater intoxication (F1,6 = 0.22; P = .97). The number (F1,50 = 0.3; P = .59) and severity (F1,50 = 2.69; P = .10) of adverse events did not differ significantly between groups. Both groups showed reduced cannabis use at follow-up, with no advantage of nabiximols over placebo for self-reported cannabis use (F1,48 = 0.29; P = .75), cannabis-related problems (F1,49 = 2.33; P = .14), or cannabis dependence (F1,50 < 0.01; P = .89). CONCLUSIONS AND RELEVANCE In a treatment-seeking cohort, nabiximols attenuated cannabis withdrawal symptoms and improved patient retention in treatment. However, placebo was as effective as nabiximols in promoting long-term reductions in cannabis use following medication cessation. The data support further evaluation of nabiximols for management of cannabis dependence and withdrawal in treatment-seeking populations. TRIAL REGISTRATION anzctr.org.au Identifier: ACTRN12611000398909.
Collapse
Affiliation(s)
- David J Allsop
- National Cannabis Prevention and Information Centre, National Drug and Alcohol Research Centre, Faculty of Medicine, University of New South Wales, Sydney, Australia2now with the School of Psychology, University of Sydney, Sydney, Australia
| | - Jan Copeland
- National Cannabis Prevention and Information Centre, National Drug and Alcohol Research Centre, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Nicholas Lintzeris
- Drug and Alcohol Services, South Eastern Sydney Local Health District New South Wales Ministry of Health, Sydney, Australia4Addiction Medicine, Central Clinical School, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Adrian J Dunlop
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, New South Wales Ministry of Health, Newcastle, Australia6School of Medicine and Public Health, Faculty of Health, University of Newcastle, Newcastle, Australia
| | - Mark Montebello
- Drug and Alcohol Services, South Eastern Sydney Local Health District New South Wales Ministry of Health, Sydney, Australia
| | - Craig Sadler
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, New South Wales Ministry of Health, Newcastle, Australia
| | - Gonzalo R Rivas
- Drug and Alcohol Services, South Eastern Sydney Local Health District New South Wales Ministry of Health, Sydney, Australia
| | - Rohan M Holland
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, New South Wales Ministry of Health, Newcastle, Australia
| | - Peter Muhleisen
- Drug and Alcohol Clinical Services, Hunter New England Local Health District, New South Wales Ministry of Health, Newcastle, Australia
| | - Melissa M Norberg
- National Cannabis Prevention and Information Centre, National Drug and Alcohol Research Centre, Faculty of Medicine, University of New South Wales, Sydney, Australia7Department of Psychology, Macquarie University, Sydney, Australia
| | - Jessica Booth
- School of Psychology, University of Sydney, Sydney, Australia
| | - Iain S McGregor
- School of Psychology, University of Sydney, Sydney, Australia
| |
Collapse
|
14
|
Allsop DJ, Copeland J, Norberg MM, Fu S, Molnar A, Lewis J, Budney AJ. Quantifying the clinical significance of cannabis withdrawal. PLoS One 2012; 7:e44864. [PMID: 23049760 PMCID: PMC3458862 DOI: 10.1371/journal.pone.0044864] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 08/09/2012] [Indexed: 11/18/2022] Open
Abstract
Background and Aims Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes.
Collapse
Affiliation(s)
- David J Allsop
- National Cannabis Prevention and Information Centre, National Drug and Alcohol Research Centre, University of New South Wales, Sydney, New South Wales, Australia.
| | | | | | | | | | | | | |
Collapse
|
15
|
Allsop DJ, Norberg MM, Copeland J, Fu S, Budney AJ. The Cannabis Withdrawal Scale development: patterns and predictors of cannabis withdrawal and distress. Drug Alcohol Depend 2011; 119:123-9. [PMID: 21724338 DOI: 10.1016/j.drugalcdep.2011.06.003] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/02/2011] [Accepted: 06/05/2011] [Indexed: 11/25/2022]
Abstract
BACKGROUND Rates of treatment seeking for cannabis are increasing, and relapse is common. Management of cannabis withdrawal is an important intervention point. No psychometrically sound measure for cannabis withdrawal exists, and as a result treatment developments cannot be optimally targeted. The aim is to develop and test the psychometrics of the Cannabis Withdrawal Scale and use it to explore predictors of cannabis withdrawal. METHODS A volunteer sample of 49 dependent cannabis users provided daily scores on the Cannabis Withdrawal Scale during a baseline week and 2 weeks of abstinence. RESULTS Internal reliability (Cronbach's alpha=0.91), test-retest stability (average intra-class correlation=0.95) and content validity analysis show that the Cannabis Withdrawal Scale has excellent psychometric properties. Nightmares and/or strange dreams was the most valid item (Wald χ²=105.6, P<0.0001), but caused relatively little associated distress (Wald χ²=25.11, P=0.03). Angry outbursts were considered intense (Wald χ²=73.69, P<0.0001) and caused much associated distress (Wald χ²=45.54, P<0.0001). Trouble getting to sleep was also an intense withdrawal symptom (Wald χ²=42.31, P<0.0001) and caused significant associated distress (Wald χ²=47.76, P<0.0001). Scores on the Severity of Dependence Scale predicted cannabis withdrawal. CONCLUSIONS The Cannabis Withdrawal Scale can be used as a diagnostic instrument in clinical and research settings where regular monitoring of withdrawal symptoms is required.
Collapse
Affiliation(s)
- David J Allsop
- National Cannabis Prevention and Information Centre, University of New South Wales, Sydney 2031, Australia.
| | | | | | | | | |
Collapse
|
16
|
Allsop DJ, Warner DA, Langkilde T, DU W, Shine R. Do operational sex ratios influence sex allocation in viviparous lizards with temperature-dependent sex determination? J Evol Biol 2006; 19:1175-82. [PMID: 16780518 DOI: 10.1111/j.1420-9101.2006.01086.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Under certain environmental situations, selection may favour the ability of females to adjust the sex ratio of their offspring. Two recent studies have suggested that viviparous scincid lizards can modify the sex ratio of the offspring they produce in response to the operational sex ratio (OSR). Both of the species in question belong to genera that have also recently been shown to exhibit temperature-dependent sex determination (TSD). Here we test whether pregnant montane water skinks (Eulamprus tympanum) utilise TSD to select offspring sex in response to population wide imbalances in the OSR, by means of active thermoregulation. We use a combination of laboratory and field-based experiments, and conduct the first field-based test of this hypothesis by maintaining females in outdoor enclosures of varying OSR treatments throughout pregnancy. Although maternal body temperature during pregnancy was influenced by OSR, the variation in temperature was not great enough to affect litter sex ratios or any other phenotypic traits of the offspring.
Collapse
Affiliation(s)
- D J Allsop
- School of Biological Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia.
| | | | | | | | | |
Collapse
|
17
|
Gardner A, Allsop DJ, Charnov EL, West SA. A Dimensionless Invariant for Relative Size at Sex Change in Animals: Explanation and Implications. Am Nat 2005; 165:551-66. [PMID: 15795852 DOI: 10.1086/429526] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Accepted: 12/16/2004] [Indexed: 11/03/2022]
Abstract
Recent comparative studies across sex-changing animals have found that the relative size and age at sex change are strikingly invariant. In particular, 91%-97% of the variation in size at sex change across species can be explained by the simple rule that individuals change sex when they reach 72% of their maximum body size. However, this degree of invariance is surprising and has proved controversial. In particular, it is not clear why this result should hold, given that there is considerable biological variation across species in factors that can influence the evolutionarily stable timing of sex change. Our overall aim here is to explain this result and determine the implications for other life-history variables. Specifically, we use a combination of approaches to formalize and make explicit previous analytical theory in this area, examine the robustness of the empirical invariance result, and carry out sensitivity analyses to determine what the empirical data imply about the mean value and variation in several key life-history variables.
Collapse
Affiliation(s)
- Andy Gardner
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom.
| | | | | | | |
Collapse
|
18
|
Abstract
Sex allocation theory is often able to make clear predictions about when individuals should facultatively adjust their offspring sex ratio (proportion male) in response to local conditions, but not the consequences for the overall population sex ratio. A notable exception to this is in sex changing organisms, where theory predicts that: (1) organisms should have a sex ratio biased toward the "first" sex: (2) the bias should be less extreme in partially sex changing organisms, where a proportion of the "second" sex matures directly from the juvenile stage; and (3) the sex ratio should be more biased in protogynous (female first) than in protandrous (male first) species. We tested these predictions with a comparative study using data from 121 sex changing animal species spanning five phyla, covering fish, arthropods, echinoderms, molluscs, and annelid worms. We found support for the first and third predictions across all species. The second prediction was supported within the protogynous species (mainly fish), but not the protandrous species (mainly invertebrates).
Collapse
Affiliation(s)
- David J Allsop
- Institute of Cell, Animal and Population Biology, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom.
| | | |
Collapse
|
19
|
|
20
|
|
21
|
Abstract
A general problem in evolutionary biology is that quantitative tests of theory usually require a detailed knowledge of the underlying trade-offs, which can be very hard to measure. Consequently, tests of theory are often constrained to be qualitative and not quantitative. A solution to this problem can arise when life histories are viewed in a dimensionless way. Recently, dimensionless theory has been developed to predict the size and age at which individuals should change sex. This theory predicts that the size at sex change/maximum size (L50/L(max)), and the age at sex change/age at first breeding (tau/alpha) should both be invariant. We found support for these two predictions across 52 species of fish. Fish change sex when they are 80% of their maximum body size, and 2.5 times their age at maturity. This invariant result holds despite a 60 and 25 fold difference across species in maximum size and age at sex change. These results suggest that, despite ignoring many biological complexities, relatively simple evolutionary theory is able to explain quantitatively at what point sex change occurs across fish species. Furthermore, our results suggest some very broad generalities in how male fitness varies with size and age across fish species with different mating systems.
Collapse
Affiliation(s)
- D J Allsop
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK.
| | | |
Collapse
|
22
|
Affiliation(s)
- David J Allsop
- Institute of Cell, Animal and Population Biology, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK.
| | | |
Collapse
|