Q. An insight into drug addiction and its effect on behavior with respect to neurobiology.
Addiction is characterized by the apparent “loss of control” or autonomy over one’s behavior.
The continued use of substances despite an apparent awareness of the adverse negative
consequences suggests that addictive behavior may involve deficits in inhibitory control,
decision making and the regulation of affect. Neuroimaging studies imply impairments in the
frontal cortical systems, which are critically involved in executive control. A major area of
concern here is why only a minority of individuals who experiment with addictive substances
develop problematic substance use patterns.
In long term alcohol drinkers, findings have shown and impairment in the domains of attention,
short term memory, visuo- spatial abilities, postural stability and executive functions, with a
relative sparing of declarative memory, language skills and primary motor and perceptual
abilities. In long term alcohol drinkers, there is disruption in the front-temporal, fronto-parietal
and cerebella’s brain systems. There is a consistent association between heavy drinking and
structural neuronal injury and volume loss that is more extensive in the frontal lobe, temporal
lobe and cerebellum. These individuals have smaller, logger and more shrunken brains. Some
alcohol related cognitive impairment and structural brain deficits can be reversed with abstinence
over a period of several months to years. Abstinence associated improvements have been
documented in neuropsychological functions such as working memory, visuospatial functioning
and attention, and are accompanied by significant increases in brain volume.
Similar to alcohol abusers, neuropsychological studies of chronic cannabis users have
demonstrated impaired performance on a variety of attention, memory and executive function
tasks. These studies showed concomitant alterations in blood flow, activation or brain tissue
density primarily in prefrontal cortical, anterior cingulate, basal ganglia, cerebellar and
hippocampal regions. On the other hand, studies on inhalant abusers show deficits in motor
coordination, learning, memory, executive functioning and overall verbal intelligence. A recent
study found substantial brain abnormalities in subcortical and white matter regions and cognitive
impairment of inhalant abusers. They also performed significantly worse on tests of working
memory, focused attention, planning and problem solving. Even within the inhalant group,
solvent abusers had more extensive and sever abnormalities in brain white matter than other
inhalant users, and these abnormalities were associated with greater cognitive impairment. Thus,
it appears that the nature and extent of neurobiological and neuropsychological impairment is
associated with the length and chronicity of the abuse, as well as the type/composition of the
volatile substance.
When it comes to opiates, studies have shown that heroin abuse has adverse effects on impulse
control but not attention or mental flexibility. However, other studies have reported more diffuse
Addiction is characterized by the apparent “loss of control” or autonomy over one’s behavior.
The continued use of substances despite an apparent awareness of the adverse negative
consequences suggests that addictive behavior may involve deficits in inhibitory control,
decision making and the regulation of affect. Neuroimaging studies imply impairments in the
frontal cortical systems, which are critically involved in executive control. A major area of
concern here is why only a minority of individuals who experiment with addictive substances
develop problematic substance use patterns.
In long term alcohol drinkers, findings have shown and impairment in the domains of attention,
short term memory, visuo- spatial abilities, postural stability and executive functions, with a
relative sparing of declarative memory, language skills and primary motor and perceptual
abilities. In long term alcohol drinkers, there is disruption in the front-temporal, fronto-parietal
and cerebella’s brain systems. There is a consistent association between heavy drinking and
structural neuronal injury and volume loss that is more extensive in the frontal lobe, temporal
lobe and cerebellum. These individuals have smaller, logger and more shrunken brains. Some
alcohol related cognitive impairment and structural brain deficits can be reversed with abstinence
over a period of several months to years. Abstinence associated improvements have been
documented in neuropsychological functions such as working memory, visuospatial functioning
and attention, and are accompanied by significant increases in brain volume.
Similar to alcohol abusers, neuropsychological studies of chronic cannabis users have
demonstrated impaired performance on a variety of attention, memory and executive function
tasks. These studies showed concomitant alterations in blood flow, activation or brain tissue
density primarily in prefrontal cortical, anterior cingulate, basal ganglia, cerebellar and
hippocampal regions. On the other hand, studies on inhalant abusers show deficits in motor
coordination, learning, memory, executive functioning and overall verbal intelligence. A recent
study found substantial brain abnormalities in subcortical and white matter regions and cognitive
impairment of inhalant abusers. They also performed significantly worse on tests of working
memory, focused attention, planning and problem solving. Even within the inhalant group,
solvent abusers had more extensive and sever abnormalities in brain white matter than other
inhalant users, and these abnormalities were associated with greater cognitive impairment. Thus,
it appears that the nature and extent of neurobiological and neuropsychological impairment is
associated with the length and chronicity of the abuse, as well as the type/composition of the
volatile substance.
When it comes to opiates, studies have shown that heroin abuse has adverse effects on impulse
control but not attention or mental flexibility. However, other studies have reported more diffuse
