Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-03T02:37:02.308Z Has data issue: false hasContentIssue false

Overlapping and disease specific trait, response, and reflection impulsivity in adolescents with first-episode schizophrenia spectrum disorders or attention-deficit/hyperactivity disorder

Published online by Cambridge University Press:  17 July 2017

J. R. M. Jepsen*
Affiliation:
Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark Child and Adolescent Mental Health Center, Mental Health Services, Capital Region of Denmark, Copenhagen, Denmark
J. Rydkjaer
Affiliation:
Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark Child and Adolescent Mental Health Center, Mental Health Services, Capital Region of Denmark, Copenhagen, Denmark
B. Fagerlund
Affiliation:
Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark
A. K. Pagsberg
Affiliation:
Child and Adolescent Mental Health Center, Mental Health Services, Capital Region of Denmark, Copenhagen, Denmark Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
R. av F. Jespersen
Affiliation:
Department of Child and Adolescent Psychiatry, Landssjúkrahusid (National Hospital), Torshavn, Faroe Islands
B. Y. Glenthøj
Affiliation:
Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
B. Oranje
Affiliation:
Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands
*
*Address for correspondence: J. R. M. Jepsen, Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS) and Center for Neuropsychiatric Schizophrenia Research (CNSR), Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark. (Email: [email protected])

Abstract

Background

Schizophrenia and attention-deficit/hyperactivity disorder (ADHD) are developmental disorders with shared clinical characteristics such as cognitive impairments and impulsivity. Impulsivity is a core feature of ADHD and an important factor in aggression, violence, and substance use in schizophrenia. Based on the hypothesis that schizophrenia and ADHD represent a continuum of neurodevelopmental impairments, the aim was to identify overlapping and disease specific forms of impulsivity.

Methods

Adolescents between 12 and 17 years of age were assessed with the Schedule for Affective Disorders and Schizophrenia for School-aged Children – Present and Lifetime Version. Subjects with early-onset, first-episode schizophrenia spectrum disorders (EOS) (N = 29) or ADHD (N = 29) and healthy controls (N = 45) were compared on two performance measures (Information Sampling Task, Stop Signal Task) and a subjective personality trait measure of impulsivity (Barratt Impulsiveness Scale, Version 11 (BIS-11)).

Results

Significantly increased reflection impulsivity was observed in ADHD but not in the EOS group. No significant response inhibition deficits (stop signal reaction time) were found in the two clinical groups. The ADHD and the EOS group showed significantly increased motor, attentional, and non-planning subtraits of impulsivity.

Conclusions

Impaired pre-decisional information gathering appeared to be specific for ADHD while the information gathering was not significantly reduced in subjects with EOS. Neither the ADHD nor EOS group showed impaired response inhibition but shared increased personality subtraits of attentional, non-planning, and motor impulsivity although the latter was significantly more pronounced in ADHD. These increased subtraits of impulsivity may reflect diagnostic non-specific neurodevelopmental impairments in ADHD and EOS in adolescence.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abel, KM, Wicks, S, Susser, ES, Dalman, C, Pedersen, MG, Mortensen, PB, Webb, RT (2010). Birth weight, schizophrenia, and adult mental disorder: is risk confined to the smallest babies? Archives of General Psychiatry 67, 923930.Google Scholar
Ahn, WY, Rass, O, Fridberg, DJ, Bishara, AJ, Forsyth, JK, Breier, A, Busemeyer, JR, Hetrick, WP, Bolbecker, AR, O'Donnell, BF (2011). Temporal discounting of rewards in patients with bipolar disorder and schizophrenia. Journal of Abnormal Psychology 120, 911921.Google Scholar
Alaghband-Rad, J, McKenna, K, Gordon, CT, Albus, KE, Hamburger, SD, Rumsey, JM, Frazier, JA, Lenane, MC, Rapoport, JL (1995). Childhood-onset schizophrenia: the severity of premorbid course. Journal of the American Academy of Child and Adolescent Psychiatry 34, 12731283.Google Scholar
Antrop, I, Stock, P, Verte, S, Wiersema, JR, Baeyens, D, Roeyers, H (2006). ADHD and delay aversion: the influence of non-temporal stimulation on choice for delayed rewards. Journal of Child Psychology and Psychiatry 47, 11521158.Google Scholar
APA (2000). Diagnostic and Statistical Manual of Mental Disorders, 4th edn, Text Revision. American Psychiatric Association: Washington.Google Scholar
APA (2013). Diagnostic and Statistical Manual of Mental Disorders, 5th edn. American Psychiatric Association: Arlington, VA.Google Scholar
Aron, AR, Fletcher, PC, Bullmore, ET, Sahakian, BJ, Robbins, TW (2003). Stop-signal inhibition disrupted by damage to right inferior frontal gyrus in humans. Nature Neuroscience 6, 115116.Google Scholar
Axelsen, MC, Jepsen, JRM, Bak, N (2017). The choice of prior in Bayesian modeling of the Information Sampling Task. Biological Psychiatry. doi: http://dx.doi.org/10.1016/j.biopsych.2017.04.021 Google Scholar
Barkley, RA, Edwards, GH, Robin, AL (1999). Defiant Teens, First Edition: A Clinician's Manual for Assessment and Family Intervention. The Guilford press: New York.Google Scholar
Bech, P (1993). Acute therapy of depression. Journal of Clinical Psychiatry 54, 1827.Google Scholar
Bellgrove, MA, Chambers, CD, Vance, A, Hall, N, Karamitsios, M, Bradshaw, JL (2006). Lateralized deficit of response inhibition in early-onset schizophrenia. Psychological Medicine 36, 495505.Google Scholar
Bennett, D, Oldham, S, Dawson, A, Parkes, L, Murawski, C, Yu, CM (2016). Systematic overestimation of reflection impulsivity in the Information Sampling Task. Biological Psychiatry. pii: S0006-3223(16)32530-6. doi: 10.1016/j.biopsych.2016.05.027. [Epub ahead of print].Google Scholar
Bennett, D, Yücel, M, Murawski, C (2017). Errors of statistical inference in the Information Sampling Task. Biological Psychiatry. doi: http://dx.doi.org/10.1016/j.biopsych.2017.05.023.Google Scholar
Biederman, J, Monuteaux, MC, Mick, E, Spencer, T, Wilens, TE, Silva, JM, Snyder, LE, Faraone, SV (2006). Young adult outcome of attention deficit hyperactivity disorder: a controlled 10-year follow-up study. Psychological Medicine 36, 167179.CrossRefGoogle ScholarPubMed
Brodsky, K, Willcutt, EG, Davalos, DB, Ross, RG (2014). Neuropsychological functioning in childhood-onset psychosis and attention-deficit/hyperactivity disorder. Journal of Child Psychology and Psychiatry 55, 811818.Google Scholar
Broome, MR, Johns, LC, Valli, I, Woolley, JB, Tabraham, P, Brett, C, Valmaggia, L, Peters, E, Garety, PA, McGuire, PK (2007). Delusion formation and reasoning biases in those at clinical high risk for psychosis. British Journal of Psychiatry 51, 3842.Google Scholar
CANTAB (2012). CANTABeclipse™ Test Administration Guide, Cambridge Automated Neuropsychological Test Assessment Battery. Manual version 5.0.0. Cambridge Cognition Limited: Cambridge.Google Scholar
Caswell, AJ, Morgan, MJ, Duka, T (2013). Inhibitory control contributes to ‘motor’ – but not ‘cognitive’ – impulsivity. Experimental Psychology 60, 324334.Google Scholar
Clark, L, Robbins, TW, Ersche, KD, Sahakian, BJ (2006). Reflection impulsivity in current and former substance users. Biological Psychiatry 60, 515522.Google Scholar
Clark, L, Roiser, J, Imeson, L, Islam, S, Sonuga-Barke, EJ, Sahakian, B (2003). Validation of a novel measure of reflection impulsivity for use in adult patient populations. Journal of Psychopharmacology 17, A36.Google Scholar
Craddock, N, Owen, MJ (2010). The Kraepelinian dichotomy – going, going… but still not gone. British Journal of Psychiatry 196, 9295.Google Scholar
Cunha-Bang, S, Stenbaek, DS, Holst, K, Licht, CL, Jensen, PS, Frokjaer, VG, Mortensen, EL, Knudsen, GM (2013). Trait aggression and trait impulsivity are not related to frontal cortex 5-HT2A receptor binding in healthy individuals. Psychiatry Research 212, 125131.Google Scholar
Dalley, JW, Everitt, BJ, Robbins, TW (2011). Impulsivity, compulsivity, and top-down cognitive control. Neuron 69, 680694.Google Scholar
Dalsgaard, S, Mortensen, PB, Frydenberg, M, Maibing, CM, Nordentoft, M, Thomsen, PH (2014). Association between Attention-Deficit Hyperactivity Disorder in childhood and schizophrenia later in adulthood. European Psychiatry 29, 259263.Google Scholar
DeVito, EE, Blackwell, AD, Clark, L, Kent, L, Dezsery, AM, Turner, DC, Aitken, MR, Sahakian, BJ (2009). Methylphenidate improves response inhibition but not reflection-impulsivity in children with attention deficit hyperactivity disorder (ADHD). Psychopharmacology 202, 531539.CrossRefGoogle Scholar
DuPaul, GI, Power, TJ, Anastopoulos, AD, Reid, R (1998). ADHD Rating Scale-IV: Checklists, Norms, and Clinical Interpretation. The Guilford Press: New York.Google Scholar
Enticott, PG, Ogloff, JRP (2006). Elucidation of impulsivity. Australian Psychologist 41, 314.Google Scholar
Erlenmeyer-Kimling, L, Rock, D, Roberts, SA, Janal, M, Kestenbaum, C, Cornblatt, B, Adamo, UH, Gottesman, II (2000). Attention, memory, and motor skills as childhood predictors of schizophrenia-related psychoses: the New York High-Risk Project. American Journal of Psychiatry 157, 14161422.Google Scholar
Ernst, M, Pine, DS, Hardin, M (2006). Triadic model of the neurobiology of motivated behavior in adolescence. Psychological Medicine 36, 299312.Google Scholar
Evans, SL, Averbeck, BB, Furl, N (2015). Jumping to conclusions in schizophrenia. Journal of Neuropsychiatric Disease and Treatment 11, 16151624.Google Scholar
Evenden, JL (1999). Varieties of impulsivity. Psychopharmacology 146, 348361.Google Scholar
Falcone, MA, Murray, RM, Wiffen, BD, O'Connor, JA, Russo, M, Kolliakou, A, Stilo, S, Taylor, H, Gardner-Sood, P, Paparelli, A, Jichi, F, Di, FM, David, AS, Freeman, D, Jolley, S (2015). Jumping to conclusions, neuropsychological functioning, and delusional beliefs in first episode psychosis. Schizophrenia Bulletin 41, 411418.Google Scholar
Fatemi, SH, Folsom, TD (2009). The neurodevelopmental hypothesis of schizophrenia, revisited. Schizophrenia Bulletin 35, 528548.Google Scholar
Fine, C, Gardner, M, Craigie, J, Gold, I (2007). Hopping, skipping or jumping to conclusions? Clarifying the role of the JTC bias in delusions. Cognitive Neuropsychiatry 12, 4677.Google Scholar
Foussias, G, Remington, G (2010). Negative symptoms in schizophrenia: avolition and Occam's razor. Schizophrenia Bulletin 36, 359369.Google Scholar
Foussias, G, Siddiqui, I, Fervaha, G, Mann, S, McDonald, K, Agid, O, Zakzanis, KK, Remington, G (2015). Motivated to do well: an examination of the relationships between motivation, effort, and cognitive performance in schizophrenia. Schizophrenia Research 166, 276282.Google Scholar
Frangou, S, Hadjulis, M, Vourdas, A (2008). The Maudsley early onset schizophrenia study: cognitive function over a 4-year follow-up period. Schizophrenia Bulletin 34, 5259.Google Scholar
Frazier, TW, Demaree, HA, Youngstrom, EA (2004). Meta-analysis of intellectual and neuropsychological test performance in attention-deficit/hyperactivity disorder. Neuropsychology 18, 543555.Google Scholar
Friedman, LA, Rapoport, JL (2015). Brain development in ADHD. Current Opinion in Neurobiology 30, 106111.Google Scholar
Garety, PA, Freeman, D (1999). Cognitive approaches to delusions: a critical review of theories and evidence. British Journal of Clinical Psychology 38, 113154.Google Scholar
Garety, PA, Freeman, D (2013). The past and future of delusions research: from the inexplicable to the treatable. British Journal of Psychiatry 203, 327333.Google Scholar
Grace, AA (1991). Phasic versus tonic dopamine release and the modulation of dopamine system responsivity: a hypothesis for the etiology of schizophrenia. Neuroscience 41, 124.Google Scholar
Groom, MJ, Jackson, GM, Calton, TG, Andrews, HK, Bates, AT, Liddle, PF, Hollis, C (2008). Cognitive deficits in early-onset schizophrenia spectrum patients and their non-psychotic siblings: a comparison with ADHD. Schizophrenia Research 99, 8595.Google Scholar
Hamilton, M (1960). A rating scale for depression. Journal Neurology, Neurosurgery and Psychiatry 23, 5662.Google Scholar
Hamshere, ML, Stergiakouli, E, Langley, K, Martin, J, Holmans, P, Kent, L, Owen, MJ, Gill, M, Thapar, A, O'Donovan, M, Craddock, N (2013). Shared polygenic contribution between childhood attention-deficit hyperactivity disorder and adult schizophrenia. British Journal of Psychiatry 203, 107111.CrossRefGoogle ScholarPubMed
Heerey, EA, Robinson, BM, McMahon, RP, Gold, JM (2007). Delay discounting in schizophrenia. Cognitive Neuropsychiatry 12, 213221.Google Scholar
Holmen, A, Juuhl-Langseth, M, Thormodsen, R, Ueland, T, Agartz, I, Sundet, K, Andreassen, OA, Rund, BR, Melle, I (2012). Executive function in early- and adult onset schizophrenia. Schizophrenia Research 142, 177182.Google Scholar
Howes, OD, Kambeitz, J, Kim, E, Stahl, D, Slifstein, M, Abi-Dargham, A, Kapur, S (2012). The nature of dopamine dysfunction in schizophrenia and what this means for treatment. Archives of General Psychiatry 69, 776786.Google Scholar
Huddy, VC, Clark, L, Harrison, I, Ron, MA, Moutoussis, M, Barnes, TR, Joyce, EM (2013). Reflection impulsivity and response inhibition in first-episode psychosis: relationship to cannabis use. Psychological Medicine 43, 20972107.Google Scholar
Huq, SF, Garety, PA, Hemsley, DR (1988). Probabilistic judgements in deluded and non-deluded subjects. Quarterly Journal of Experimental Psychology 40, 801812.Google Scholar
Jepsen, JR, Fagerlund, B, Pagsberg, AK, Christensen, AM, Nordentoft, M, Mortensen, EL (2010). Deficient maturation of aspects of attention and executive functions in early onset schizophrenia. European Child and Adolescent Psychiatry 19, 773786.Google Scholar
Johnson, JK, Tuulio-Henriksson, A, Pirkola, T, Huttunen, MO, Lonnqvist, J, Kaprio, J, Cannon, TD (2003). Do schizotypal symptoms mediate the relationship between genetic risk for schizophrenia and impaired neuropsychological performance in co-twins of schizophrenic patients? Biological Psychiatry 54, 12001204.Google Scholar
Johnson, S, Hollis, C, Kochhar, P, Hennessy, E, Wolke, D, Marlow, N (2010). Psychiatric disorders in extremely preterm children: longitudinal finding at age 11 years in the EPICure study. Journal of the American Academy of Child and Adolescent Psychiatry 49, 453463.Google Scholar
Kagan, J (1965). Individual differences in the resolution of response uncertainty. Journal of Personality and Social Psychology 2, 154160.Google Scholar
Kagan, J (1966). Reflection – impulsivity: the generality and dynamics of conceptual tempo. Journal of Abnormal Psychology 71, 1724.CrossRefGoogle ScholarPubMed
Kaladjian, A, Jeanningros, R, Azorin, JM, Anton, JL, Mazzola-Pomietto, P (2011). Impulsivity and neural correlates of response inhibition in schizophrenia. Psychological Medicine 41, 291299.Google Scholar
Karatekin, C, Asarnow, RF (1998). Working memory in childhood-onset schizophrenia and attention-deficit/hyperactivity disorder. Psychiatry Research 80, 165176.Google Scholar
Karatekin, C, White, T, Bingham, C (2008). Divided attention in youth-onset psychosis and attention deficit/hyperactivity disorder. Journal of Abnormal Psychology 117, 881895.Google Scholar
Karatekin, C, White, T, Bingham, C (2010). Shared and nonshared symptoms in youth-onset psychosis and ADHD. Journal of Attention Disorders 14, 121131.Google Scholar
Kaufman, J, Birmaher, B, Brent, D, Rao, U, Flynn, C, Moreci, P, Williamson, D, Ryan, N (1997). Schedule for affective disorders and schizophrenia for school-age children-present and lifetime version (K-SADS-PL): initial reliability and validity data. Journal of the American Academy of Child and Adolescent Psychiatry 36, 980988.Google Scholar
Kay, SR, Fiszbein, A, Opler, LA (1987). The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13, 261276.Google Scholar
Keshavan, M, Montrose, DM, Rajarethinam, R, Diwadkar, V, Prasad, K, Sweeney, JA (2008). Psychopathology among offspring of parents with schizophrenia: relationship to premorbid impairments. Schizophrenia Research 103, 114120.Google Scholar
Keshavan, MS, Diwadkar, VA, Montrose, DM, Rajarethinam, R, Sweeney, JA (2005). Premorbid indicators and risk for schizophrenia: a selective review and update. Schizophrenia Research 79, 4557.Google Scholar
Keshavan, MS, Sujata, M, Mehra, A, Montrose, DM, Sweeney, JA (2003). Psychosis proneness and ADHD in young relatives of schizophrenia patients. Schizophrenia Research 59, 8592.Google Scholar
Kim-Cohen, J, Caspi, A, Moffitt, TE, Harrington, H, Milne, BJ, Poulton, R (2003). Prior juvenile diagnoses in adults with mental disorder: developmental follow-back of a prospective-longitudinal cohort. Archives of General Psychiatry 60, 709717.Google Scholar
Leucht, S, Kane, JM, Kissling, W, Hamann, J, Etschel, E, Engel, RR (2005). What does the PANSS mean? Schizophrenia Research 79, 231238.Google Scholar
Lipszyc, J, Schachar, R (2010). Inhibitory control and psychopathology: a meta-analysis of studies using the stop signal task. Journal of the International Neuropsychological Society 16, 10641076.Google Scholar
Lowther, C, Costain, G, Stavropoulos, DJ, Melvin, R, Silversides, CK, Andrade, DM, So, J, Faghfoury, H, Lionel, AC, Marshall, CR, Scherer, SW, Bassett, AS (2014). Delineating the 15q13.3 microdeletion phenotype: a case series and comprehensive review of the literature. Genetics in Medicine 17, 149157.Google Scholar
Maibing, CF, Pedersen, CB, Benros, ME, Mortensen, PB, Dalsgaard, S, Nordentoft, M (2015). Risk of schizophrenia increases after all child and adolescent psychiatric disorders: a nationwide study. Schizophrenia Bulletin 41, 963970.Google Scholar
McClellan, J, Breiger, D, McCurry, C, Hlastala, SA (2003). Premorbid functioning in early-onset psychotic disorders. Journal of the American Academy of Child and Adolescent Psychiatry 42, 666672.Google Scholar
Menon, M, Pomarol-Clotet, E, McKenna, PJ, McCarthy, RA (2006). Probabilistic reasoning in schizophrenia: a comparison of the performance of deluded and nondeluded schizophrenic patients and exploration of possible cognitive underpinnings. Cognitive Neuropsychiatry 11, 521536.Google Scholar
Moutoussis, M, Bentall, RP, El-Deredy, W, Dayan, P (2011). Bayesian modelling of Jumping-to-Conclusions bias in delusional patients. Cognitive Neuropsychiatry 16, 422447.CrossRefGoogle ScholarPubMed
Nandagopal, JJ, Fleck, DE, Adler, CM, Mills, NP, Strakowski, SM, DelBello, MP (2011). Impulsivity in adolescents with bipolar disorder and/or attention-deficit/hyperactivity disorder and healthy controls as measured by the Barratt Impulsiveness Scale. Journal of Child and Adolescent Psychopharmacology 21, 465468.Google Scholar
Nieto, RG, Castellanos, FX (2011). A meta-analysis of neuropsychological functioning in patients with early onset schizophrenia and pediatric bipolar disorder. Journal of Clinical Child and Adolescent Psychology 40, 266280.Google Scholar
Nikolas, MA, Burt, SA (2010). Genetic and environmental influences on ADHD symptom dimensions of inattention and hyperactivity: a meta-analysis. Journal of Abnormal Psychology 119, 117.Google Scholar
Ochoa, S, Haro, JM, Huerta-Ramos, E, Cuevas-Esteban, J, Stephan-Otto, C, Usall, J, Nieto, L, Brebion, G (2014). Relation between jumping to conclusions and cognitive functioning in people with schizophrenia in contrast with healthy participants. Schizophrenia Research 159, 211217.Google Scholar
Oie, M, Sundet, K, Rund, BR (1999). Contrasts in memory functions between adolescents with schizophrenia or ADHD. Neuropsychologia 37, 13511358.Google Scholar
Oie, M, Sundet, K, Rund, BR (2010). Neurocognitive decline in early-onset schizophrenia compared with ADHD and normal controls: evidence from a 13-year follow-up study. Schizophrenia Bulletin 36, 557565.Google Scholar
Ouzir, M (2013) Impulsivity in schizophrenia: a comprehensive update. Aggression and Violent Behavior 18, 247254.Google Scholar
Owen, MJ, O'Donovan, MC, Thapar, A, Craddock, N (2011). Neurodevelopmental hypothesis of schizophrenia. British Journal Psychiatry 198, 173175.Google Scholar
Pattij, T, Vanderschuren, LJ (2008). The neuropharmacology of impulsive behaviour. Trends in Pharmacological Sciences 29, 192199.Google Scholar
Patton, JH, Stanford, MS, Barratt, ES (1995). Factor structure of the Barratt impulsiveness scale. Journal of Clinical Psychology 51, 768774.Google Scholar
Phillips, LD, Edwards, W (1966). Conservatism in a simple probability inference task. Journal of Experimental Psychology 72, 346354.Google Scholar
Reddy, LF, Lee, J, Davis, MC, Altshuler, L, Glahn, DC, Miklowitz, DJ, Green, MF (2014). Impulsivity and risk taking in bipolar disorder and schizophrenia. Neuropsychopharmacology 39, 456463.Google Scholar
Ross, RG, Compagnon, N (2001). Diagnosis and treatment of psychiatric disorders in children with a schizophrenic parent. Schizophrenia Research 50, 121129.Google Scholar
Ross, RG, Heinlein, S, Tregellas, H (2006). High rates of comorbidity are found in childhood-onset schizophrenia. Schizophrenia Research 88, 9095.Google Scholar
Russell, AT, Bott, L, Sammons, C (1989). The phenomenology of schizophrenia occurring in childhood. Journal of the American Academy of Child and Adolescent Psychiatry 28, 399407.Google Scholar
Schiffer, B, Muller, BW, Scherbaum, N, Forsting, M, Wiltfang, J, Leygraf, N, Gizewski, ER (2010). Impulsivity-related brain volume deficits in schizophrenia-addiction comorbidity. Brain 133, 30933103.Google Scholar
Sebat, J, Levy, DL, McCarthy, SE (2009). Rare structural variants in schizophrenia: one disorder, multiple mutations; one mutation, multiple disorders. Trends in Genetics 25, 528535.Google Scholar
Shin, YS, Kim, SN, Shin, NY, Jung, WH, Hur, JW, Byun, MS, Jang, JH, An, SK, Kwon, JS (2013). Increased intra-individual variability of cognitive processing in subjects at risk mental state and schizophrenia patients. PLoS ONE 8, e78354.CrossRefGoogle ScholarPubMed
Shurman, B, Horan, WP, Nuechterlein, KH (2005). Schizophrenia patients demonstrate a distinctive pattern of decision-making impairment on the Iowa Gambling Task. Schizophrenia Research 72, 215224.Google Scholar
Sikstrom, S, Soderlund, G (2007). Stimulus-dependent dopamine release in attention-deficit/hyperactivity disorder. Psychological Review 114, 10471075.Google Scholar
Silva, D, Colvin, L, Hagemann, E, Bower, C (2014). Environmental risk factors by gender associated with attention-deficit/hyperactivity disorder. Pediatrics 133, e14e22.Google Scholar
Sonuga-Barke, EJ (1994). Annotation: on dysfunction and function in psychological theories of childhood disorder. Journal of Child Psychology and Psychiatry 35, 801815.Google Scholar
Sonuga-Barke, EJ (2003). The dual pathway model of AD/HD: an elaboration of neuro-developmental characteristics. Neuroscience and Biobehavioral Reviews 27, 593604.Google Scholar
Sonuga-Barke, EJ (2005). Causal models of attention-deficit/hyperactivity disorder: from common simple deficits to multiple developmental pathways. Biological Psychiatry 57, 12311238.Google Scholar
Sonuga-Barke, EJ, De, HJ, De, RK, Ajzenstzen, M, Holland, S (2004). AD/HD and the capture of attention by briefly exposed delay-related cues: evidence from a conditioning paradigm. Journal of Child Psychology and Psychiatry 45, 274283.Google Scholar
Stanford, MS, Mathias, CW, Dougherty, DM, Lake, SL, Anderson, NE, Patton, JH (2009). Fifty years of the Barratt Impulsiveness Scale: an update and review. Personality and Individual Differences 47, 385395.Google Scholar
Sullivan, PF, Kendler, KS, Neale, MC (2003). Schizophrenia as a complex trait: evidence from a meta-analysis of twin studies. Archives of General Psychiatry 60, 11871192.Google Scholar
Swanson, JM, Kinsbourne, M, Nigg, J, Lanphear, B, Stefanatos, GA, Volkow, N, Taylor, E, Casey, BJ, Castellanos, FX, Wadhwa, PD (2007). Etiologic subtypes of attention-deficit/hyperactivity disorder: brain imaging, molecular genetic and environmental factors and the dopamine hypothesis. Neuropsychological Review 17, 3959.Google Scholar
Taylor Tavares, JV, Clark, L, Cannon, DM, Erickson, K, Drevets, WC, Sahakian, BJ (2007). Distinct profiles of neurocognitive function in unmedicated unipolar depression and bipolar II depression. Biological Psychiatry 62, 917924.Google Scholar
Turner, DC, Robbins, TW, Clark, L, Aron, AR, Dowson, J, Sahakian, BJ (2003). Cognitive enhancing effects of modafinil in healthy volunteers. Psychopharmacology 165, 260269.Google Scholar
van Os, J, Kapur, S (2009). Schizophrenia. Lancet 374, 635645.Google Scholar
Verdejo-Garcia, A, Lawrence, AJ, Clark, L (2008). Impulsivity as a vulnerability marker for substance-use disorders: review of findings from high-risk research, problem gamblers and genetic association studies. Neuroscience and Biobehavioral Reviews 32, 777810.Google Scholar
Vollema, MG, Postma, B (2002). Neurocognitive correlates of schizotypy in first degree relatives of schizophrenia patients. Schizophrenia Bulletin 28, 367377.Google Scholar
Wechsler, D (1997). Wechsler Adult Intelligence Scale. 3rd edn. The Psychological Corporation Limited: London.Google Scholar
Wechsler, D (2002). Wechsler Adult Intelligence Scale – Third Edition, Wechsler Memory Scale – Third Edition. Technical Manual. The Psychological Corporation. A Harcourt Assessment Company: USA.Google Scholar
Wechsler, D (2003). Manual for the Wechsler Intelligence Scale for Children, 4th edn. Technical and Interpretative Manual. Psychological Corporation: San Antonio.Google Scholar
Willcutt, EG, Doyle, AE, Nigg, JT, Faraone, SV, Pennington, BF (2005). Validity of the executive function theory of attention-deficit/hyperactivity disorder: a meta-analytic review. Biological Psychiatry 57, 13361346.Google Scholar
Winstanley, CA, Eagle, DM, Robbins, TW (2006). Behavioral models of impulsivity in relation to ADHD: translation between clinical and preclinical studies. Clinical Psychology Review 26, 379395.Google Scholar
Yanofski, J (2010). The dopamine dilemma: using stimulants and antipsychotics concurrently. Psychiatry 7, 1823.Google Scholar
Yun, DY, Hwang, SS, Kim, Y, Lee, YH, Kim, YS, Jung, HY (2011). Impairments in executive functioning in patients with remitted and non-remitted schizophrenia. Progression in Neuro-Psychopharmacology and Biological Psychiatry 35, 11481154.Google Scholar
Zhornitsky, S, Rizkallah, E, Pampoulova, T, Chiasson, JP, Lipp, O, Stip, E, Potvin, S (2012). Sensation-seeking, social anhedonia, and impulsivity in substance use disorder patients with and without schizophrenia and in non-abusing schizophrenia patients. Psychiatry Research 200, 237241.Google Scholar