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A Dynamic Developmental Theory of Attention-Deficit /Hyperactivity Disorder (ADHD) Predominantly Hyperactive/Impulsive and Combined Subtypes

Sagvolden, Terje, Johansen, Espen Borgå, Aase, Heidi and Russell, Vivienne Ann A Dynamic Developmental Theory of Attention-Deficit /Hyperactivity Disorder (ADHD) Predominantly Hyperactive/Impulsive and Combined Subtypes.

Short Abstract:

ADHD (Attention-Deficit/Hyperactivity Disorder) is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. There is no biological marker distinguishing ADHD from normality. Consequently, a behavioral theory of ADHD is offered. The theory suggests that hypofunctioning dopamine systems play pivotal roles by producing altered reinforcement processes and deficient extinction of previously reinforced behavior. These will, on a behavioral level, give rise to delay aversion, development of hyperactivity in novel situations, impulsiveness, deficient sustained attention, increased behavioral variability, and failure to inhibit responses (“disinhibition”). It might be that the disorder in the future should be named RED (Reinforcement/Extinction Disorder). (101 words)

Long Abstract:

ADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Presently, it is evident that the disorder primarily will have to be explained behaviorally. Inattentiveness, overactivity, and impulsiveness are presently regarded as the main clinical symptoms of ADHD. Inattention is, however, a characteristic of most psychiatric disorders. It is argued that the ADHD Inattentive subtype may have heterogeneous origins and be qualitatively different from the ADHD Hyperactive/Impulsive and Combined subtypes. A dynamic developmental behavioral theory based on reinforcement and extinction processes is offered. The theory suggests that hypofunctioning dopamine systems play pivotal roles. There might be two independent underlying main factors causing ADHD: altered reinforcement processes and deficient extinction of previously reinforced behavior that primarily may be associated with a hypofunctioning mesolimbic dopamine system. These factors probably interact with effects of other hypofunctioning dopamine systems: Deficient orienting responses and poor behavioral organization that primarily may be associated with a hypofunctioning mesocortical dopamine system. Impaired starting and stopping of responses; impaired acquisition, retrieval and relearning of programs for sequential motor tasks; and poor nondeclarative habit learning that primarily may be associated with a hypofunctioning nigrostriatal dopaminergic system. Dopamine is a neuromodulator that tunes the activity of other neurons. The theory offers an explanation of why ADHD is not a pathology that represents a separate entity with behavior qualitatively distinct from normal behavior, but is a case where the functions of the central nervous system occasionally exceeds the limits of normal variation and adaptation. (247 words)

Keywords:	catecholamine, clumsiness, hyperkinesis, hyperkinetic disorder, monoamine, overactivity, pollutants, reward, soft signs, variability
Subjects:	Psychology: Behavioral Analysis Neuroscience: Behavioral Neuroscience Neuroscience: Neuropsychiatry
ID code:	bbs00001214
Deposited by:	Terje Sagvolden on 26 April 2002