title: A prospective study of neurocognitive changes 15 years after chronic inhalant abuse.
abstract: OBJECTIVE
  In a previous study, neurological and cognitive deficits reflecting central nervous system (CNS) disruption from chronic inhalant abuse showed substantial recovery after 2 years' abstinence. Functional recovery was progressive, with recovery rates dependent on the degree of impairment prior to abstinence, and severity and duration of initial abuse. Persistent deficits occurred in those with previous 'lead encephalopathy' from leaded petrol abuse. The current study examined recovery in the same cohort 15 years after baseline.
  
  
  METHODS
  Prospective cohort design.
  
  
  METHODS
  Two remote Aboriginal communities in Arnhem Land, Australia.
  
  
  METHODS
  Using baseline group classifications, 27 healthy controls, 60 ex-chronic inhalant abusers and an additional 17 with previous lead encephalopathy were assessed.
  
  
  METHODS
  Standard neurological, ocular-motor and cognitive functions and blood lead levels.
  
  
  RESULTS
  Chronic (non-encephalopathic) inhalant abusers showed elevated blood lead levels and abnormal scores on most tasks at baseline. At 2 years' abstinence, blood lead was reduced but remained elevated and most scores had normalized. By 15 years, blood lead and all performance scores were equivalent to healthy controls for this group (P > 0.05). The encephalopathic group was more severely impaired on all scores at baseline and showed little improvement, if any, across all tests after both 2 and 15 years' abstinence. Blood lead for this group declined, and was not significantly different to controls after 15 years.
  
  
  CONCLUSIONS
  Some inhalant abusers experience severe and persistent neurological deficits, suggesting irrecoverable damage attributable to lead encephalopathy. In the absence of this encephalopathy long-term abstinence from inhalants may allow recovery of normal brain function.
authors.affiliation: Menzies School of Health Research, Institute of Advanced Studies, Charles Darwin University, Darwin, NT, Australia. Sheree.Cairney@menzies.edu.au
authors.forename: Sheree
authors.initials: S
authors.lastname: Cairney
authors.forename: Nicole
authors.initials: N
authors.lastname: O' Connor
authors.forename: Kylie M
authors.initials: KM
authors.lastname: Dingwall
authors.forename: Paul
authors.initials: P
authors.lastname: Maruff
authors.forename: Ruxanna
authors.initials: R
authors.lastname: Shafiq-Antonacci
authors.forename: Jon
authors.initials: J
authors.lastname: Currie
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
mesh_terms: D000328:Adult; D002493:Central Nervous System Diseases / Q000208:ethnology / Q000209:etiology*; D002908:Chronic Disease; D003072:Cognition Disorders / Q000208:ethnology / Q000209:etiology*; D005500:Follow-Up Studies; D006801:Humans; D058545:Inhalant Abuse / Q000208:ethnology / Q000523:psychology*; D008297:Male; D015876:Northern Territory / Q000208:ethnology; D010364:Pattern Recognition, Visual / Q000187:drug effects; D011446:Prospective Studies; D011930:Reaction Time / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D012438:Saccades / Q000187:drug effects