title: Different psychological effects of cannabis use in adolescents at genetic high risk for schizophrenia and with attention deficit/hyperactivity disorder (ADHD).
abstract: BACKGROUND
  Controversy exists regarding whether young people at risk for schizophrenia are at increased risk of adverse mental effects of cannabis use.
  
  
  METHODS
  We examined cannabis use and mental health functioning in three groups of young people aged 14-21; 36 non-psychotic siblings of adolescents with schizophrenia (genetic high risk group), 25 adolescents with attention deficit hyperactivity disorder (ADHD) and 72 healthy controls. The groups were sub-divided into 'users' and 'non-users' of cannabis based on how often they had used cannabis previously. Mental health functioning was quantified by creating a composite index derived from scores on the Schizotypal Personality Questionnaire (SPQ), Strengths and Difficulties Questionnaire (SDQ) and Global Assessment of Function (GAF).
  
  
  RESULTS
  A significant positive association between cannabis use and mental health disturbance was confined to young people at genetic high risk for schizophrenia. To determine whether the relationship was specific to particular dimensions of mental health function, a second composite index was created based on scores from the SPQ Disorganisation and SDQ hyperactivity-inattention sub-scales. Again, there was a significant positive association between cannabis use and factor scores which was specific to the genetic high risk group. There was a trend for this association to be negative in the ADHD group (p=0.07).
  
  
  CONCLUSIONS
  The findings support the view that young people at genetic high risk for schizophrenia are particularly vulnerable to mental health problems associated with cannabis use. Further research is needed to investigate the basis of relationships between cannabis and mental health in genetically vulnerable individuals.
authors.affiliation: Developmental Psychiatry, University of Nottingham, E Floor, South Block, Queens Medical Centre, Derby Road, Nottingham, England NG7 2UH, UK. chris.hollis@nottingham.ac.uk
authors.forename: Chris
authors.initials: C
authors.lastname: Hollis
authors.forename: Madeleine J
authors.initials: MJ
authors.lastname: Groom
authors.forename: Debasis
authors.initials: D
authors.lastname: Das
authors.forename: Tim
authors.initials: T
authors.lastname: Calton
authors.forename: Alan T
authors.initials: AT
authors.lastname: Bates
authors.forename: Hayley K
authors.initials: HK
authors.lastname: Andrews
authors.forename: Georgina M
authors.initials: GM
authors.lastname: Jackson
authors.forename: Peter F
authors.initials: PF
authors.lastname: Liddle