?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=The+development+of+conditioned+blocking+and+monoamine+metabolism+in+children+with+attention-deficit-hyperactivity+disorder+or+complex+tics+and+healthy+controls%3A+an+exploratory+analysis&rft.creator=Oades%2C+R.D.&rft.creator=M%C3%BCller%2C+B.&rft.subject=Clinical+Psychology&rft.subject=Cognitive+Psychology&rft.subject=Neuropsychiatry&rft.description=Introduction%3A+%0AConditioned+blocking+(CB)+measures+the+transient+suppression+of+learning+that+a+new+stimulus%2C+added+during+learning%2C+has+the+same+consequences+as+the+conditioned+stimulus+already+present.+Normal+CB+increases+from+puberty+across+adolescence%2C+between+the+age+of+8+and+20+years+(Oades+et+al.%2C+1996).+Is+there+a+delay+in+the+development+of+selective+attention+abilities+in+children+with+a+primary+diagnosis+of+attention-deficit%2Fhyperactivity+disorder+(ADHD)+and+does+this+differ+from+children+with+Tourette+syndrome+who+also+express+some+symptoms+of+attention+deficit%3F+%0A%0AMethods%3A+%0ACB+development+was+compared+between+13+healthy+children+(CN%3A+mean+age+11.0+years)%2C+13+with+attention-deficit%2Fhyperactivity+disorder+(ADHD%3A+mean+10.5y)+and+11+with+complex+tic+or+Tourette+syndrome+who+also+showed+some+attention-deficit+symptoms+(TS%3A+mean+11.8y).+The+ADHD+group+were+medication+naive%2C+but+3+TS+were+receiving+tiapride%2C+and+two+pimozide.+The+'mouse-in-house'+task+form+was+used.+%0A%0AResults%3A+%0A1.+All+children+required+fewer+trials+to+learn+the+task+with+increasing+age%3A+(the+ADHD+group+was+slightly+slower).+%0A2.+However%2C+only+healthy+controls+improved+CB+with+increasing+age+(figure+1%2C+left).+%0A3.+TS+patients+under+11y+tended+to+show+impaired+CB%2C+and+over+11y+they+were+significantly+worse+than+controls.+%0A4.+While+ADHD+children+over+11y+showed+less+CB+than+controls%2C+under+11y+they+tended+to+show+more+CB.+%0A5.+A+correlational+analysis+of+the+status+of+monoamine+metabolism+in+24h+urine+samples+showed+a+positive+relationship+for+CB+with+dopamine+(DA)+metabolism+in+normal+and+TS+children%2C+but+a+negative+relationship+in+ADHD+patients+(figure+1%2C+right).+%0A6.+In+contrast%2C+increases+of+serotonin+(5-HT)+metabolism+were+negatively+related+to+CB+in+TS%2C+but+positively+related+to+CB+in+ADHD+children+(figure+1%2C+right).%0A7.+Both+ADHD+and+TS+groups+showed+a+depressed+NA+turnover+compared+to+normal+children%3A+but+the+ADHD+showed+a+marked+suppression+of+the+ratio+of+DA+and+5HT+metabolites+(i.e.+HVA%2F5HIAA)+that+reflected+their+higher+5-HIAA+levels.+%5BThe+TS+group+showed+increased+DA+turnover+possibly+reflecting+medication.%5D+see+figure+2.+%0A%0AConclusions%3A+%0AWhen+selective+information+processing+abilities+reflected+by+CB+start+to+develop+at+the+onset+of+puberty%2C+there+is+a+relative+worsening+in+ADHD+patients.+In+contrast+TS+patients+show+an+impairment+independent+of+age.+Changes+in+the+balance+between+dopamine+and+serotonin+systems+may+contribute+to+normal+and+to+abnormal+cognitive+development.+%0A&rft.publisher=Elsevier&rft.date=1997&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Fcogprints.org%2F1120%2F2%2FBBR-oades-mull.pdf&rft.identifier=++Oades%2C+R.D.+and+M%C3%BCller%2C+B.++(1997)+The+development+of+conditioned+blocking+and+monoamine+metabolism+in+children+with+attention-deficit-hyperactivity+disorder+or+complex+tics+and+healthy+controls%3A+an+exploratory+analysis.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F1120%2F