ABSTRACT Attention Deficit/Hyperactivity Disorder (ADHD) is characterised by developmentally inappropriate levels of inattention, impulsivity and hyperactivity. As might be expected of a disorder in which inhibitory deficits form part of the diagnostic criteria, deficits in response inhibition in ADHD have been evidenced in a number of studies. To date, the tasks used in such studies have required participants to inhibit the learned stimulus-response associations that result in unwanted behavior. However, no research has examined the inhibition of stimulus-stimulus associations, formally ‘conditioned inhibition’. The present study used video game conditioned inhibition procedures, developed for children and adolescents with a clinical diagnosis of ADHD and suitable for typically developing matched controls. Two computer-based tasks (‘Mission to Mars’ and ‘Weapon-X’) required participants to predict the occurrence of an outcome based on the stimuli presented. We selected 12 male participants with ADHD on medication (methylphenidate), but without comorbid Tourette Syndrome, pervasive developmental disorder, learning disability or psychosis. This group showed overall normal inhibition of stimulus-stimulus associations, measured repeatedly over trials and with two task variants. There was no correlation between inhibitory learning and symptom severity ratings. However, participants with ADHD on higher dosages of methylphenidate, or longer duration of treatment with methylphenidate, showed improved ability to anticipate outcomes following the different stimulus presentations on non-inhibited versus inhibited trials. This effect was most clearly demonstrated on the Weapon-X task. Thus, methylphenidate doserelatedly improved the expression of associative learning. This action may contribute to its therapeutic effects in improving cognitive function in ADHD.
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nullKantini, E. , Cassaday, H. , Batty, M. , Hollis, C. and Jackson, G. (2011) Associative learning in ADHD: improved expression under methylphenidate. Open Journal of Psychiatry, 1, 20-29. doi: 10.4236/ojpsych.2011.12004.
 American Psychiatric Association (2000) Diagnostic and statistical manual of mental disorders, fourth edition, text revision (DSM-IV-TR). American Psychiatric Association, Washington.
Barkley, R.A. (1998) Attention-deficit/hyperactivity disorder: A handbook for diagnosis and treatment. 2nd Edition, Guilford Press, New York, 75-143.
Faraone, S.V., Sergeant, J., Gillberg, C. and Biederman, J. (2003) The worldwide prevalence of ADHD: Is it an American condition? World Psychiatry, 2, 104-113.
Kytja, K.S. and Voeller, M.D. (2004) Attention-Deficit hyperactivity disorder (ADHD). Journal of Child Neurology, 19, 798-814.
Iaboni, F., Douglas, V.I. and Baker, A.G. (1995) Effects of reward and response costs on inhibition in ADHD children. Journal of Abnormal Psychology, 104, 232-240.
 Schachar, R. and Logan, G.D. (1990) Impulsivity and inhibitory control in normal development and childhood psychopathology. Developmental Psychology, 26, 710-720. doi:10.1037/0012-16188.8.131.520
Schachar, R., Mota, V.L., Logan, G.D., Tannock, R. and Klim, P. (2000) Confirmation of an inhibitory control deficit in attention-deficit/hyperactivity disorder. Journal of Abnormal Child Psychology, 28, 227-235.
Seidman, L.J., Biederman, J., Faraone, S.V., Wever, W. and Ouellette, C. (1997) Toward defining a neuropsychology of attention deficit-hyperactivity disorder: Performance of children and adolescents from a large clinically referred sample. Journal of Consulting and Clinical Psychology, 65, 150-160.
Trommer, B.L., Hoeppner, J.-A.B., Lorber, R. and Armstrong, K.J. (1988) The Go-No-Go paradigm in attention deficit disorder. Annals of Neurology, 24, 610-614.
Young, S., Bramham, J., Tyson, C. and Morris, R. (2006) Inhibitory dysfunction on the Stroop in adults diagnosed with attention deficit hyperactivity disorder. Personality and Individual Differences, 41, 1377-1384.
Oades, R.D. and Müller, B. (1997) The development of conditioned blocking and monoamine metabolism in children with attention-deficit-hyperactivity disorder or complex tics and healthy controls: An exploratory analysis. Behavioural Brain Research, 88, 95-102.
Rescorla, R.A. and Wagner, A.R. (1972) A theory of Pavlovian conditioning: Variations in the effectiveness of reinforcement and nonreinforcement. In: Black, A.H., Prokasy, W.F., Eds., Classical Conditioning II: Current Research and Theory, Appleton-Century-Crofts, New York, 64-99.
Escobar, M., Oberling, P. and Miller, R.R. (2002) Associative deficit accounts of disrupted latent inhibition and blocking in schizophrenia. Neuroscience & Biobehavioral Reviews, 26, 203-216.
Rescorla, R.A. (1969) Pavlovian conditioned inhibition. Psychological Bulletin, 72, 77-94. doi:10.1037/h0027760
Miller, R.R. and Matzel, L.D. (1988) The comparator hypothesis: A response rule for the expression of associations. In: Gordon, H. B. Ed., Psychology of Learning and Motivation, Academic Press, Waltham, 51-92.
Kantini, E., Cassaday, H.J., Hollis, C.P. and Jackson, G.M. (2011) The normal inhibition of associations is impaired by clonidine in Tourette syndrome. Journal of the Canadian Academy of Child and Adolescent Psychiatry, 20, 96-106.
Migo, E.M., Corbett, K., Graham, J., Smith, S., Tate, S., Moran, P.M. et al. (2006) A novel test of conditioned inhibition correlates with personality measures of schizotypy and reward sensitivity. Behavioural Brain Research, 168, 299-306. doi:10.1016/j.bbr.2005.11.021
Langleben, D.D., Monterosso, J., Elman, I., Ash, B., Krikorian, G. and Austin, G. (2006) Effect of methylphenidate on Stroop color-word task performance in children with attention deficit hyperactivity disorder. Psychiatry Research, 141, 315-320.
Lopez, F., Silva, R., Pestreich, L. and Muniz, R. (2003) Comparative efficacy of two once daily methylphenidate formulations (Ritalin LA and Concerta) and placebo in children with attention deficit hyperactivity disorder across the school day. Pediatric Drugs, 5, 545-555.
Harmer, C.J. and Phillips, G.D. (1999) Enhanced conditioned inhibition following repeated pretreatment with d-amphetamine. Psychopharmacology, 142, 120-131.
 Batty, M.J., Liddle, E.B., Pitiot, A., Toro, R., Groom, M.J., Scerif, G., et al. (2010) Cortical gray matter in attention-deficit/hyperactivity disorder: A structural magnetic resonance imaging study. Journal of the American Academy of Child and Adolescent Psychiatry, 49, 229-238.
Groom, M.J., Gaia, S., Liddle, P.F., Batty, M.J., Liddle, E.B., Roberts, K.L., et al. (2010) Effects of motivation and medication on electrophysiological markers of response inhibition in children with attention deficithyperactivity disorder. Biological Psychiatry, 67, 624-631.
Goodman, R., Ford, T., Richards, H., Gatward, R. and Meltzer, H. (2000) The development and well-being assessment: Description and initial validation of an integrated assessment of child and adolescent psychopathology. Journal of Child Psychology and Psychiatry and Allied Disciplines, 41, 645-655.
Goodman, R. (1997) The strengths and difficulties questionnaire: A research note. Journal of Child Psychology and Psychiatry and Allied Disciplines, 38, 581-586.
Goodman, R. (2001) Psychometric properties of the strengths and difficulties questionnaire. Journal of the American Academy of Child and Adolescent Psychiatry, 40, 1337-1345. doi:10.1097/00004583-200111000-00015
Conners, C.K. (1997) Conner’s rating scales-revised: Technical manual. Multi-Health Systems, Toronto.
Rutter, M., Bailey, A. and Lord, C. (2003) Social communication questionnaire: Manual. Western Psychological Services, Los Angeles.
Abelson, R.P. (1995) Statistics as principled argument. Lawrence Erlbaum Associates, Hove, 104-131.
Bitsakou, P., Psychogiou, L., Thompson, M. and Sonuga-Barke, E.J.S. (2008) Inhibitory deficits in attention deficit/hyperactivity disorder are independent of basic processing efficiency and IQ. Journal of Neural Transmission, 115, 261-268.
Karazinov, D.M. and Boakes, R.A. (2007) Second-order conditioning in human predictive judgements when there is little time to think. Quarterly Journal of Experimental Psychology, 60, 448-460.
Mitchell, C.J., Livesey, E. and Lovibond, P.F. (2007) A dissociation between causal judgement and the ease with which a cause is categorized with its effect. Quarterly Journal of Experimental Psychology, 60, 400-417.
Holland, P.C. (1984) Differential effects of reinforcement of an inhibitory feature after serial and simultaneous feature negative discrimination training. Journal of Experimental Psychology: Animal Behavior Processes, 10, 461-475. doi:10.1037/0097-7403.10.4.461
 Holland, P.C. and Lamarre, J. (1984) Transfer of inhibition after serial and simultaneous feature negative discrimination training. Learning and Motivation, 15, 219-243. doi:10.1016/0023-9690(84)90020-1
Horsley, R.R. and Cassaday, H.J. (2007) Methylphenidate can reduce selectivity in associative learning in an aversive trace conditioning task. Journal of Psychopharmacology, 21, 492-500.
Cassaday, H.J., Finger, B.C. and Horsley, R.R. (2008) Methylphenidate and nicotine focus responding to an informative discrete CS over successive sessions of appetitive conditioning. Journal of Psychopharmacology, 22, 849-859. doi:10.1177/0269881107083842
Lansbergen, M.M., Kenemans, J.L. and van Engeland, H. (2007) Stroop interference and attention-deficit/hyperactivity disorder: A review and meta-analysis. Neuropsychology, 21, 251-262. doi:10.1037/0894-4184.108.40.206
Scheres, A., Oosterlaan, J., Swanson, J., Morein-Zamir, S., Meiran, N., Schut, H., et al. (2003) The effect of methylphenidate on three forms of response inhibition in boys with AD/HD. Journal of Abnormal Child Psychology, 31, 105-120. doi:10.1023/A:1021729501230