Beyond diagnoses : attention deficit hyperactivity disorder vs. early onset bipolar disorder : A study of neurological diversity behind symptoms
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The distinction between Bipolar Disorder (BD) and Attention Deficit/Hyperactivity Disorder (ADHD) in youths is difficult because of similar behaviour presentation. Delayed diagnosis and treatment of early onset psychiatric disorders is associated with considerable morbidity and mortality, and an adverse effect on psychosocial development and academic achievement. Identifying neuromotor and neurocognitive problems underlying similar symptoms may perhaps aid diagnostic accuracy, and also be valuable in the understanding of daily life problems and facilitate tailored education.
Specific aims of this thesis were as follows:
Is there a symptom overlap between ADHD and BD as measured by parent and teacher rated ADHD questionnaires? May performance on tests of neuromotor and neuropsychological test differ between youths fulfilling the diagnostic criteria of ADHD, BD and subgroups of BD? Can neuromotor and neuropsychological tests performance promote diagnostic accuracy in differentiating ADHD from BD in clinical practice? Is ADHD in the context of BD similar to ADHD that occurs alone?
Design: Cross- sectional study:
BD vs. ADHD vs. ADHD+BD vs. Control
Sixty-eight children and adolescents aged 6-18 years, who fulfilled the DSM-IV diagnostic criteria for BD (I, II, NOS), ADHD combined type (ADHD-C) or both. Concerning the neuropsychological data, 69 controls examined primarily for another study, were included for comparison.
Diagnostic interview: Kiddie-Schedule for Affective Disorders and Schizophrenia Present and Lifetime version (KSADS-PL). Questionnaires: ADHD rating scale-IV. (Other questionnaires provided characteristics of the clinical sample, and were not analyzed as dependent variables (Achenbach System of Empirically Based Assessment check list (ASEBA), Mood and feelings questionnaire (MFQ), Parent General Behaviour Inventory 10 item (PGBI-10)).
Soft sign and motor test:
The Neuromotor examination for children; NUBU. Neuropsychological tests: Wechsler’s Intelligence Scales (WISC-III and WAIS-III). Continuous Performance Test-II, Children’s Checking Task, Stroop Test, Wisconsin Card Sorting Test, Children’s Auditory Verbal Learning Test-II, Knox Cube Test.
The main findings in this thesis were:
ADHD-rating scale-IV scores from home and school scores are elevated in both BD and ADHD-C, and may lead to misdiagnosis of comorbid ADHD in BD (paper II).
The positive predictive value of NUBU in the diagnosis of ADHD-C was 89% for ‘Total soft signs’ and 87% for ‘Static coordination’ below the 7.5 percentile (Paper I).
ADHD-C in the context of BD may be pathophysiologically similar to ADHD that occurs alone, while the inattentive type of ADHD occurring in the setting of BD is mainly an artefact due to overlapping symptoms with BD (Papers I - II). Though there are somewhat different neuropsychological profiles in BD and ADHD-C, these cannot be used to differentiate between the disorders due to low sensitivity (Papers II- IV):
- Deficit semantic organizing and long-term memory was specific to the BD subgroup with a history of psychotic symptoms. ADHD-C had no genuine memory deficit.
- Increased reaction time variability (inattention) was specific to ADHD-C, but characterized only about half of those with ADHD-C diagnosis.
- All clinical groups demonstrated impaired processing speed.
- The ADHD-C group and the BD subgroup with a history of psychotic symptoms both demonstrated some executive problems; these were partly speed-dependent.
Neither neuropsychological tests nor parent and teacher rated ADHDsymptom questionnaires differentiate ADHD from BD. Neuromotor tests does. Inattentive symptoms in BD are not related to the inattentive type of ADHD. Cognitive deficits in BD characterize mainly those with a history of psychotic symptoms. Processing speed characterize all BD subgroups and also ADHD-C. Some executive problems are speeddependent. These findings may have important implications for everyday diagnostic work and perhaps facilitate interventions in order to prevent functional impairments. The findings may also lend insight into the neurobiological systems that are disrupted in these disorders.
List of papers. Paper II is removed from the thesis due to copyright restrictions.
Paper I Udal A.H., Malt U.F., Lövdahl H., Gjaerum B., Pripp A.H., Groholt B. (2009) Motor function may differentiate attention deficit hyperactivity disorder from early onset Bipolar disorder. Behav Brain Funct, 5(47). doi:10.1186/1744-9081-5-47 Published under a Creative Commons Attribution License.
Paper II Udal A.H, Øygarden B., Egeland J., Malt U.F., Lövdahl H., Pripp A.H., Groholt B. (2011) Differentiating between comorbidity and symptom overlap in ADHD and bipolar disorder –a pilot study. Submitted august 2011.
Paper III Udal A.H, Øygarden B., Egeland J., Malt U.F., Lövdahl H., Pripp A.H., Groholt B. (2011) Executive deficits in early onset bipolar disorder compared to attention-deficit hyperactivity disorder: impact of processing speed and a history of psychotic symptoms. Clin Child Psychol Psychiatry September 13, 2012 doi:10.1177/1359104512455181
Paper IV Udal A.H., Øygarden B., Egeland J., Malt U.F., Groholt B. (2012) Memory in Early Onset Bipolar Disorder and Attention-Deficit/Hyperactivity Disorder: Similarities and Differences, J Abnorm Child Psychol. 40(7) 1179-1192. The original publication is available at www.springerlink.com. doi:10.1007/s10802-012-9631-x