Lecture 1
Defining characteristics of drug addiction :
- Tolerance
- Craving
- Euphoria
- Problems with law enforcement
- Loss of control
- Withdrawal
- Desire to quit
- Relapse
Definitions – addiction process
Drug addiction - brief definition :
A substance-related psychiatric disorder characterized by :
- A persistent loss of control
- Obsessive craving
- Chronic relapse
NB : Tolerance and withdrawal can occur, but relapse is not necessarily associated with these
phenomena
Drug-centered views on addiction
1. Negative reinforcement theory
2. Positive reinforcement theory
3. Neuroadaptation theory
The repetition of a habit based off a relationship with a stimuli, is known as reinforcement.
Reinforcement can be either classified as positive or negative. Both reinforcement types increase
drug usage in this context. Reinforcement is usually facilitated by an external stimuli or some sort of
trigger, by adding to the desired effect, or removing of an aversive stimuli. The key result of any
“reinforcement”, is that it maintains the behaviour, in the case of addiction, the drug using process,
regardless of it being positive or negative reinforcement.
,For example, someone who needs to achieve higher grades in school, who studies better while using
a certain drug, may continue to be reinforced to use it, as the drug use helps them study longer, and
results in better grades. Alternatively, someone battling depression may discover that using a drug
may provide enough relief to temporarily soothe their low or sad mood, and depending on the
substance, continues using it. In the first example, adding the drug leads to (positive) better grades
and reinforces further drug usage. In the later example, using the drug removes (negative) the
aversive situation, depression, which reinforces further drug usage. Both result in maintaining or
increasing drug usage.
Negative reinforcement theory (anhedonia)
Negative reinforcement theory of addiction = negative reinforcement, suggests that individuals
continue to use drugs, despite negative consequences, because it alleviates uncomfortable states or
sensations such as those associated with negative mood states, tension, arousal, craving, or
withdrawal. For some individuals, these uncomfortable states and situations develop as a symptom
of withdrawal following periods of prolonged use. For others, even initial use can be used as a
maladaptive coping mechanism to alleviate aversive states that existed prior to drug use such as
depression, anxiety, or reduced responsivity to reward. Negative reinforcement can include someone
who abuses a drug and get used to its effects, then stops and feels withdrawal, and now has to
continue its usage to avoid the aversive situation
PRO :
- Drugs can be used to alleviate pain and symptoms of anxiety and depression
- Drug use abolishes the withdrawal symptoms, thereby maintaining drug-taking behaviour
CON:
- Feelings of anhedonia (=the inability to feel pleasure) do not necessarily explain drug use
- Drug use can be continued in the absence of withdrawal symptoms
- Alleviating withdrawal signs by means of pharmacotherapy does not prevent relapse
- Relapse can occur long after withdrawal signs have dissipated
Examples :
Positive reinforcement theory (euphoria)
Positive reinforcement theory of addiction= Drug use is commonly understood as providing
immediate short-term reward. This acute positive effect of the substance (e.g., euphoria and/or high)
can be seen behaviourally and within brain regions implicated in reward, including medial
orbitofrontal cortex (OFC), rostral anterior cingulate cortex (ACC), and ventral striatum, in frequent
users as well as substance-naïve individuals. When these positive feeling states outweigh the
,negative consequences and perpetuate use, drug-seeking behaviour is said to be positively
reinforced.
PRO :
- Drugs of abuse induce euphoria and are therefore addictive
- Because of these euphoria-inducing effects drug-taking behaviour is maintained
CON :
- No clear relationship between the euphoria-producing effects of drugs and their abuse
potential (cf. tobacco)
- The long-term negative consequences of drug use (e.g. on health and well-being) definitely
outweigh the short-lasting euphoria, yet drug use is not discontinued in addicts
Examples :
Neuroadaptation model
Definition :
- Structural and functional adaptations in the brain induced by repeated drug use underlie
addictive behaviour
- The brain’s reward system becomes sensitized to drugs and drug associated stimuli. These
stimuli lead to intense feelings of drug craving
In addition :
- Continued drug use impairs prefrontal cortical function
- Drug use becomes compulsive and inflexible
- Some neuroadaptive changes may be permanent, producing the persistent sense of
discomfort during abstinence that leads to reinstatement of drug use (i.e., relapse).
, The downward spiral of drug addiction
Summary :
Drug addiction :
- Is a multi-faced disorder
- Is a process, rather than a state
- Is considered as a disorder of the brain
Defining characteristics of drug addiction :
- Tolerance
- Craving
- Euphoria
- Problems with law enforcement
- Loss of control
- Withdrawal
- Desire to quit
- Relapse
Definitions – addiction process
Drug addiction - brief definition :
A substance-related psychiatric disorder characterized by :
- A persistent loss of control
- Obsessive craving
- Chronic relapse
NB : Tolerance and withdrawal can occur, but relapse is not necessarily associated with these
phenomena
Drug-centered views on addiction
1. Negative reinforcement theory
2. Positive reinforcement theory
3. Neuroadaptation theory
The repetition of a habit based off a relationship with a stimuli, is known as reinforcement.
Reinforcement can be either classified as positive or negative. Both reinforcement types increase
drug usage in this context. Reinforcement is usually facilitated by an external stimuli or some sort of
trigger, by adding to the desired effect, or removing of an aversive stimuli. The key result of any
“reinforcement”, is that it maintains the behaviour, in the case of addiction, the drug using process,
regardless of it being positive or negative reinforcement.
,For example, someone who needs to achieve higher grades in school, who studies better while using
a certain drug, may continue to be reinforced to use it, as the drug use helps them study longer, and
results in better grades. Alternatively, someone battling depression may discover that using a drug
may provide enough relief to temporarily soothe their low or sad mood, and depending on the
substance, continues using it. In the first example, adding the drug leads to (positive) better grades
and reinforces further drug usage. In the later example, using the drug removes (negative) the
aversive situation, depression, which reinforces further drug usage. Both result in maintaining or
increasing drug usage.
Negative reinforcement theory (anhedonia)
Negative reinforcement theory of addiction = negative reinforcement, suggests that individuals
continue to use drugs, despite negative consequences, because it alleviates uncomfortable states or
sensations such as those associated with negative mood states, tension, arousal, craving, or
withdrawal. For some individuals, these uncomfortable states and situations develop as a symptom
of withdrawal following periods of prolonged use. For others, even initial use can be used as a
maladaptive coping mechanism to alleviate aversive states that existed prior to drug use such as
depression, anxiety, or reduced responsivity to reward. Negative reinforcement can include someone
who abuses a drug and get used to its effects, then stops and feels withdrawal, and now has to
continue its usage to avoid the aversive situation
PRO :
- Drugs can be used to alleviate pain and symptoms of anxiety and depression
- Drug use abolishes the withdrawal symptoms, thereby maintaining drug-taking behaviour
CON:
- Feelings of anhedonia (=the inability to feel pleasure) do not necessarily explain drug use
- Drug use can be continued in the absence of withdrawal symptoms
- Alleviating withdrawal signs by means of pharmacotherapy does not prevent relapse
- Relapse can occur long after withdrawal signs have dissipated
Examples :
Positive reinforcement theory (euphoria)
Positive reinforcement theory of addiction= Drug use is commonly understood as providing
immediate short-term reward. This acute positive effect of the substance (e.g., euphoria and/or high)
can be seen behaviourally and within brain regions implicated in reward, including medial
orbitofrontal cortex (OFC), rostral anterior cingulate cortex (ACC), and ventral striatum, in frequent
users as well as substance-naïve individuals. When these positive feeling states outweigh the
,negative consequences and perpetuate use, drug-seeking behaviour is said to be positively
reinforced.
PRO :
- Drugs of abuse induce euphoria and are therefore addictive
- Because of these euphoria-inducing effects drug-taking behaviour is maintained
CON :
- No clear relationship between the euphoria-producing effects of drugs and their abuse
potential (cf. tobacco)
- The long-term negative consequences of drug use (e.g. on health and well-being) definitely
outweigh the short-lasting euphoria, yet drug use is not discontinued in addicts
Examples :
Neuroadaptation model
Definition :
- Structural and functional adaptations in the brain induced by repeated drug use underlie
addictive behaviour
- The brain’s reward system becomes sensitized to drugs and drug associated stimuli. These
stimuli lead to intense feelings of drug craving
In addition :
- Continued drug use impairs prefrontal cortical function
- Drug use becomes compulsive and inflexible
- Some neuroadaptive changes may be permanent, producing the persistent sense of
discomfort during abstinence that leads to reinstatement of drug use (i.e., relapse).
, The downward spiral of drug addiction
Summary :
Drug addiction :
- Is a multi-faced disorder
- Is a process, rather than a state
- Is considered as a disorder of the brain
