title: Hand function is altered in individuals with a history of illicit stimulant use.
abstract: Use of illicit stimulant drugs such as methamphetamine, cocaine, and ecstasy are a significant worldwide problem. However, little is known about the effect of these drugs on movement. The aim of the current study was to investigate hand function in adults with a history of illicit stimulant use. We hypothesized that prior use of illicit stimulant drugs is associated with abnormal manipulation of objects. The study involved 22 subjects with a history of illicit stimulant use (aged 29±8 yrs; time since last use: 1.8±4.0 yrs) and two control groups comprising 27 non-drug users (aged 25±8 yrs) and 17 cannabis users with no history of stimulant use (aged 22±5 yrs). Each subject completed screening tests (neuropsychological assessment, medical history questionnaire, lifetime drug history questionnaire, and urine drug screen) prior to gripping and lifting a light-weight object with the dominant right hand. Horizontal grip force, vertical lift force, acceleration, and first dorsal interosseus electromyographic (EMG) activity were recorded during three trials. In trial one, peak grip force was significantly greater in the stimulant group (12.8±3.9 N) than in the control groups (non-drug: 10.3±4.6 N; cannabis: 9.4±2.9 N, P<0.022). However, peak grip force did not differ between groups in trials two and three. The results suggest that individuals with a history of stimulant use overestimate the grip force required to manipulate a novel object but, are able to adapt grip force in subsequent lifts. The results suggest that movement dysfunction may be an unrecognized consequence of illicit stimulant use.
authors.affiliation: School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, South Australia, Australia.
authors.forename: Verity
authors.initials: V
authors.lastname: Pearson-Dennett
authors.affiliation: School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, South Australia, Australia.
authors.forename: Stanley C
authors.initials: SC
authors.lastname: Flavel
authors.affiliation: Department of Neurology, Flinders Medical Centre, South Australia, Australia; Human Physiology, Medical School, Flinders University, South Australia, Australia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wilcox
authors.affiliation: School of Health Sciences and Sansom Institute, University of South Australia, South Australia, Australia.
authors.forename: Dominic
authors.initials: D
authors.lastname: Thewlis
authors.affiliation: Speech Neuroscience Unit, University of Melbourne, Victoria, Australia.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Vogel
authors.affiliation: School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, South Australia, Australia.
authors.forename: Jason M
authors.initials: JM
authors.lastname: White
authors.affiliation: School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, South Australia, Australia.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Todd
mesh_terms: D000293:Adolescent; D000328:Adult; D002188:Cannabis; D005260:Female; D006225:Hand / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D013287:Illicit Drugs / Q000494:pharmacology*; D017770:Lifting; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D008875:Middle Aged; D009048:Motor Skills / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D009483:Neuropsychological Tests; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D008694:Methamphetamine; D018817:N-Methyl-3,4-methylenedioxyamphetamine