ADHD. Dr Carel Ziervogel. Acknowledgement to Prof. A Rostain, U. Penn.

Transcription

1 ADHD Dr Carel Ziervogel Acknowledgement to Prof. A Rostain, U. Penn.

2 DSM 4 Criteria AD/HD Inattention Impulsivity Hyperactivity Persistent i.e. some Sx. before 7 yrs. Pervasive Impairment of functioning

3 Clinical experience Prevalence of a family history of ADD Prevalence of symptoms in a parent

4 Epidemiology Childhood prevalence: 4.6% 25 y. full criteria : 15% -partial criteria: 65% (Faraone et al., 2006)

5 Some Limitations of the DSM Approach to ADHD Medical model Categorical approach Age-based criteria Lack of unifying conceptual framework Symptom-focus rather than functional status focus

6 Beyond the ADHD Holy Grail Diagnosis is heterogeneous and dimensional there are limits to a categorical approach to classification of developmental disorders ( Axis 1.5 ) Course is affected by numerous factors (e.g. severity of symptoms, environmental stressors and supports, co-morbidity, personality traits, intellect, resilience vs. vulnerability) Treatment response and prognosis are variable ADHD can be defined as both a syndrome and as a neurobiological predisposition to delays in socialemotional development, impulse control and the ability to internalize rules of behavior

7 Social Evolution Hunter gatherer Pastoralist Industrialised urbanised Increasing organisational & time management demands

8 New Concepts About ADHD Newer definitions emphasize impairments in executive functioning No single neurobiological or neuropsychological theory can explain the heterogeneity seen in ADHD No single neuropsychological test can be used to diagnose ADHD it is a clinical diagnosis Co-morbidity is the rule rather than the exception The interactions between ADHD and co-morbid conditions are multiplicative (rather than additive)

9 Executive Functions (EF) Wide range of central control processes previously referred to as frontal lobe functions Connect, prioritize and integrate cognitive functions - moment by moment Structures and interconnections are not fully developed at birth and show continuous development into early adulthood Depend upon neuronal mylenization, synaptic pruning, elaboration of dopamine & norepinephrine systems, etc. Can become impaired developmentally, traumatically and/or secondary to disease processes Environmental demands for EF increase with age from preschool through adulthood

10 Core Symptoms of ADHD Behavioral activation difficulties Disorganization, lack of readiness Poor planning and execution skills Information processing problems Inattention, distractibility Slower processing speed Poor time management Inconsistent effort and follow through Poor persistence at effortful tasks More sensitive to interruption Slower to resume task once interrupted

11 Core Symptoms of ADHD Memory deficits Forgetfulness Impaired verbal memory, recall Affect regulation difficulties Anger, temper outbursts Anxiety Emotional lability / instability Problem-solving impairment Diminished self-control ( discipline ) Interpersonal problems

12 Figure 1. Many of the so-called executive functions are subserved by the prefrontal cortex. Lesions to the PFC in the right hemisphere in humans can produce a profile of behavioral disinhibition similar to ADHD. PFC, prefrontal cortex; ADHD, attentiondeficit/hyperactivity disorder. From Arnsten & Li, 2005

13 Dual Systems of Attention Posterior system orients to and engages novel stimuli; localized to the superior parietal cortex, the superior colliculus and the pulvinar. It receives dense NE innervation from the LC which inhibits the spontaneous activity of postsynaptic neurons thereby increasing signal to noise ratio of target neurons (i.e. orientation) Anterior system in the PFC and the anterior cingulate that subserves the executive system. It is modulated by ascending DA fibers from the VTA. DA suppresses spontaneous activity of target neurons and reduces their responsivity to new inputs (i.e. better focusing)

14 Dual Systems of Attention

15 Management Psycho-education Environmental management Psycho-stimulant medication - methylphenidate Atomoxetine Treat co-morbidity Follow up