Drug driving risk and impacts on road safety - PowerPoint Presentation

1. Drug driving risk and impacts on road safetyA/Professor Michael FitzharrisACCIDENT RESEARCH CENTRE

2. Context – effects of drugs and relationship to drivingIllicit drugs have known ‘psychoactive effects’, with direct effects on cognition and body physiology that are outwardly expressed as particular behavioural changes and changes to ‘motor control’.Different drugs have very different effects, but generally include:Altered state of consciousness;Altered sense of space and time;Changes to cognition, including changes in reaction time and decision-making;Changes to motor control, impacting on co-ordination including hand-eye co-ordination, andChanges to mood state, which can range from euphoria through to feeling ‘chilled’ or relaxed.It is well accepted that these skills are needed for the safe control of motor vehicles.While the principal focus is on illicit drugs and driving, prescription medications such as opioid analgesics and benzodiazepines can also have deleterious effects on these same skills needed for safe driving.There is a vast amount of research evidence from simulator studies, closed on-road trials and a different range of crash-based studies that highlight the increased crash risk following consumption of particular drugs.

3. Effects of select illicit drugs, incl. immediate, come-down, withdrawalCannabis (THC)AmphetaminesMethamphet / iceEcstasy (MDMA)CocaineHeroinKavaDepressant StimulantStimulantStimulantStimulantDepressantDepressantSmoked, eatenSwallow, inject, smoke, snortSmoked, injected, snorted, swallowPill: swallow; (freq. not pure MDMA)Powder snort, inject; crystals / crack: smoke Powder, granules, rock; injected or smokedDrink (root crushed, chewed, ground→ soaked); OTC prep.Time course of and type of effectsImmediately if smoked; eat: hourImmediate, overdose riskPotent, immediate (3-7 sec. smoked)Within 20-60 min. depend how usedImmediateImmediate; longer if snortedHours; Feel relaxed, sleepy; laugh, excitement;Increased appetite;Dry mouth;Quiet, reflectiveConfidence; talking more, energetic, repetitive behavior; Large pupils and dry mouth; reduced appetite6 hour time-course; similar to amphetamines, more extremeHighly addictive with regular useUp to 6 hour effects; happy, energetic, confidentDilated pupils, jaw clenching, nauseaheat strokeHappy, confident; Alert; feel physically strong, mentally sharp, unpredictable behaviorEffect last 3-5 hrs. Intense pleasure and pain relief;slurred speech, drowsy, clumsy, confusionHas sedative, hypnotic, muscle relaxant effects (simular to alcohol); for insomnia, stress relief, anxietyLarger amounts: Trouble concentrateBlurred vision; Slower reflexesBloodshot eyesLong-term: memory loss, psychosis ‘Come down’: exhaustion; dizziness, blurred vision, paranoia, confusion; irritablePsychosis: violent, aggressiveCome down takes days; ‘ice psychosis’ common (hallucinations, bizarre behaviour); (see amphet)Larger: anxietyHallucinationsirrational behavior,, irritability, paranoia; Days after: restless sleep, exhaustionanxiety, depressionHigher doses: paranoid delusions, hallucinations and out of character aggressive behavior; come down last daysOverdose risk; difficulty concentrating; falling asleep (‘nod’); Come down ~ 2 days, irritable, depressionHappy, relaxed, mild sleep (dose dependent →drowsy); pupil dilaton, nausea; Long-term: moody, apathy ; +Dep/SCZMost common used: 10% last 12-months; 34% lifetime1.4% last 12-months6.4% lifetimeFirst use: 18 yearsPer amphetamines category2.2% last 12-months11.2% lifetimeFirst use: 18 years2.5% last 12-months9% lifetimeFirst use: 19 years1.3% last 12-months0.2% lifetimeFirst use: 16.9 yrsNo data in Australia+++effects alcohol↑ risk: THC, Bz, Alco+MDMA/speed: stroke; +BZ: OD+Antidepressants: clumsy, dizzySee other stimulants+stimulants OD risk+depress: ↓breath+ACLO: ↑drowsy+BZ: sedationUsed post other drugs; social useTransport and shift workers; party drugPervasive, dominant youngParty drugSocial useDependent usersSocial, cultural

4. Common patterns of use and implications for drivingPolydrug use is common; that is, multiple drugs are be consumed at (or roughly) the same time, including with alcohol.For polydrug users, each drug has a different purpose:Example: THC / cannabis is used to help with the ‘come down’ effects of MDMA and amphetaminesNeed to consider not simply the immediate acute effects of drugs on driving (which can last hours), but the effects of the ‘come down’ which can take days, depending on drug and dose.The purpose for taking the drug, and the location, is an important consideration when looking at the relationship to driving and implications for likely enforcement effectiveness. We distinguish between context and type of use. Usage ContextFactorsType of useOccupationalSocialMedicinalIsolated +/- alcohol+/- fatigue+ other illicit drugs+ opioids / benzodiazepineOccasionalAmphetamines, cocaineCocaine, MDMA, MATHCMARegularAmphetamines, cocaineCocaine, MDMA, MATHCHeroin, MADependentAmphetamines, cocaineCocaine, MATHCHeroin, MA

5. Do people drive after consuming drugs?In Victoria, large numbers are detected at the roadside (~6000 in 2015) with one of the three target drugs (amphetamine: 77%, THC: 37%; MDMA: 5%); previously (10 years ago) THC was the majority.Approximately 20% of drivers killed test positive for one of these illicit drugs.Evidence from Burnett Institute in Melbourne demonstrates high levels of driving among known drug users; reported in two sentinel reporting system (EDRS, IDRS):60% of EDRS users drove in last 6-months after use; median time: 60 min, 5 times.85% injecting users drove last 6-months after use; median time: 30 min, 18 times.Horyniak & Dietze, 2015 (Burnett Institute, for MUARC)

6. Crash risk by drugs: findings from a systematic review CannabisAmphetaminesCocaineKavaNo. studies4010101 study in FijiNo. case-control19961Risk estimate range (OR) 1-4(1.5 – 2.0)8.9-54.82.11-4.54.70 (95%CI: 1.90–11.63).% studies dose-response relationship found100% (of 4)N/AN/ADifference in acute (within 12hr use) vs. use over past 12 months (2x higher risk than no use)% studies increased risk for polydrug use100% (of 2)100% (of 2)100% (of 1)PAF of 18% - reduce serious injury crashes by 18% by avoiding driving post-Kava useLarge volume of research examining crash risk and drug use.Different study designs have been used (case-control, responsibility studies, observational).Study designs have different features and specific limitations, some including how drug use is assessed and whether levels of drug use are examined with a view to impairment level.Well designed studies adjust for potential confounders like age, alcohol, experience to isolate effect of drug on crash risk.Summary of crash risk studies and selected drugsWainiqolo et al., PLOS One, 2014

7. Road-based drug testing programsAustralia is among one of an increasing number of countries that test for drugs whilst driving (e.g., Ireland, Norway).Australia tests for amphetamines, THC and MDMA; others assess more, including prescription medications (i.e., Norway).Australia assesses for the presence of drugs in saliva and blood, known as ‘per se laws’, while other jurisdictions set an impairment-based drug level (e.g., UK) by setting devices at a different threshold level.Important and complex debate on ‘per se’ vs. ‘impairment’ given type of drug and effects, how used, time-course of effects, half-life of drugs and elimination, and device sensitivity.Davey et al., 2014, Accident Analysis and PreventionVictoria introduced laws in 2004 (THC, amphetamines), and added MDMA in 2006.Targeted approach to testing, with a focus on known at-risk groups.

8. Considerations for drug-driving crash risk and enforcement programs Crash risk differs depending on type of drug used, and how it is used.There are immediate effects of drugs that impact skills needed for driving, but also negative effects in the ‘come down’ period (where other drugs can also be used)Drug withdrawal introduces a host of other risks, and may be thought to be limited to regular heavy users and dependent users.For understanding likely impact of enforcement, need to also consider the percent drug use in the target population by type, as well as the known higher crash risk.Critical to understand drug culture and preferences, where people use, and how this shifts over time with emerging drugs and supply / pricing issues.The effectiveness of enforcement will differ depending on: target drug, the user population (context), and their level of use (occasional, regular, dependent).It is likely that enforcement alone will be effective for occasional users of THC, MDMA and amphetamines among occupational users.For regular heavy users and dependent users, particularly MA (‘ice’) and heroin (currently not tested), therapeutic justice models and drug courts will also be required.