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Background: Central nervous system-depressant (CNS-Ds) drugs can impair cognitive functions and driving. They are also the most common drugs taken in overdose in hospital-treated episodes of self-poisoning. In Australia most of these patients are discharged within 48 h, while they still have possible subclinical drug effects. We aimed to determine whether patients treated for self-poisoning with CNS-Ds are impaired in the Trail-Making Test (TMT, parts A and B), a neuropsychological test that is known to correlate with driving performance., Methods: This study was a conducted from November 2008 to April 2011 in a referral center for poisonings in New South Wales, Australia. One hundred seven patients discharged from the clinical toxicology unit following treatment for self-poisoning of CNS-Ds (benzodiazepines, atypical antipsychotics, or opioids) and a control group of 68 discharged following self-poisoning of non-CNS-depressant drugs (acetaminophen or nonsedating antidepressants) were tested with the TMT (parts A and B). Due to the known association of impaired TMT with driving impairment and increased risk of traffic accidents, performance less than the 10th percentile for age was defined as significant impairment in each part of the TMT. The odds ratio (OR) for impairment in each part was calculated in multivariate logistic regression (MLR) models adjusted for gender, education, IQ, and the presence of a major psychiatric illness. A secondary MLR analysis was conducted only for those patients (78 CNS-D and 54 control group participants) who were directly discharged home, after excluding those who were transferred for further psychiatric care., Results: The odds of impairment in the CNS-D group was 2.8 times that of the control group on the TMT-A (38 [35.5%] vs. 11 [16.2%]: adjusted OR = 2.76, 95% confidence interval [CI]: 1.28-5.97), and 4.6 times on the TMT-B (67 [62.6%] vs. 22 [32.4%]: adjusted OR = 4.63, 95% CI: 2.06-10.42). The results were similar in the subgroup of patients discharged home, and the odds of impairment in the CNS-D group was 3.3 times that of the control group on the TMT-A (25 [32.1%] vs. 7 [13.0%]: adjusted OR = 3.30, 95% CI: 1.28-8.52), and 3.6 times on the TMT-B (46 [59.0%] vs. 17 [31.5%]: adjusted OR = 3.64, 95% CI: 1.44-9.20). TMT-B impairment in the CNS-D group remained significant even after adjusting for TMT-A performance., Conclusions: Patients with CNS-D overdose may have significant impairment in cognitive skills underlying driving at the time of discharge from hospitals. Clinicians should warn these patients that their driving skills might still be impaired, even if they are considered clinically recovered and advise them not to drive during the first 1 to 2 days following discharge.

Background: Use of psychotropic drugs is known to impair driving and increase the risk of road traffic accidents. They are also the most common drugs taken in overdose in hospital-treated episodes of self-poisoning. Most patients who take psychotropic drug overdoses are discharged within 48 hours, while they still have possible subclinical drug effects., Objective: Using a self-controlled case series design, we aimed to determine whether patients with psychotropic drug overdose are at a higher risk of a traffic accident in the period following discharge compared with a control period not associated with hospital-treated drug overdose., Methodology: Using the New South Wales (NSW) Admitted Patient Data Collection (APDC) as the primary source, we retrieved 40 845 hospital separation records dated between 1 July 2000 and 30 June 2008 (8 years) in patients aged 18-80 years admitted to a hospital in NSW following an intentional self-poisoning with a psychotropic drug (coded X61 or X62 as the International Classification of Diseases, 10th Edition, [ICD-10] external cause of injury). Of these, 33459 hospital separations (i.e. discharges, transfers and deaths) involving 24 284 patients were considered eligible as the patients were discharged directly into the community where they could have driven a motor vehicle. We selected three separate post-admission periods (3 days, 1 week and 4 weeks), subtracted the number of inpatient days from each and calculated three separate post-discharge periods (immediate, intermediate and extended, respectively) for each episode of overdose. The control period was the duration of the study period where the individual was aged 18 years or older, excluding the total person-days in the post-discharge period/s and the index inpatient period/s. The APDC dataset was linked to the NSW Roads and Traffic Authority CrashLink dataset to identify any accidents in which each patient was involved as a motor-vehicle driver during the follow-up period. Incidence rate ratio (IRR) for matched post-discharge and control periods was found using random effects Poisson regression., Results: Seventy-two percent of the subjects were discharged within 2 days following their admission with overdose. Compared with the corresponding control periods the risk of a traffic accident was 3.5 times higher (IRR = 3.49; 95% CI 1.66, 7.33; p = 0.001) during the immediate, 1.9 times higher (IRR = 1.88; 95% CI 1.09, 3.25; p = 0.023) during the intermediate and 1.6 times higher (IRR = 1.65; 95% CI 1.27, 2.15; p = 0.0002) during the extended post-discharge period., Conclusions: Self-poisoning with psychotropic drugs is associated with a markedly increased risk of a traffic accident during the first few days following discharge. These findings raise clinical and medico-legal implications concerning fitness-to-drive during this period. The risk reduces with time but remains significantly elevated after 4 weeks post-overdose. Further research is necessary to find out the factors contributing to this ongoing risk.