PHYSICAL DEPENDENCY
A result of long term use. For example, daily use for weeks or months.
A physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is
discontinued. For example, delirium tremors with alcohol cessation.
In fact normal day-to-day functioning can become reliant on the substance. For example, having an
alcoholic drink before work.
Often accompanied by tolerance. For example, the user requires increased doses in order to obtain
the same desired effect.
PSYCHOLOGICAL DEPENDENCY
The condition that exists when a person must continue to take a drug in order to satisfy intense
mental and emotional craving for the drug.
The individual thinks that they cannot cope with work and social life without a particular drug such as
alcohol or nicotine.
Absence of the drug causes the individual to feel anxious, irritable or depressed, and have cravings
for the substance.
Thus the addiction is in the mind and becomes the central focus to a person's life.
TOLERANCE
The diminishing effect with regular use of the same dose of a drug (or behaviour), requiring the user
to take larger and larger doses (or behaviours) before experiencing the same effect.
The body's adjustment to chronic use
Can occur in at least 3 ways:
● Metabolic tolerance - where enzymes responsible for breaking down the drug become more
effective reducing its effect
● Neuroadaptation – where changes at the synapse occur e.g. downregulation may make
receptors less sensitive or fewer in number; reducing the effects of drugs/behaviours
● Learned tolerance – is the result of practice as the person has learned to function normally
whilst under the influence of drug (and dealing with its effects)
WITHDRAWAL SYNDROME
Unpleasant physical or psychological effects following discontinued use of a drug,
Can include shakes or tremors, vomiting, blood pressure/heart rate changes. Depends on the
drug/behaviour. Recovery should be idiosyncratic (specific) to the substance.
These effects are the consequence of the body reacting to cessation of the drug
This often leads onto relapse as users find withdrawal symptoms intolerable
2 types:
● Acute withdrawal (within hours but usually stops within weeks)
● Post acute withdrawal (brain slowly reorganises and balances which could take months or
years)
DEFINING ADDICTIONS
Walters, 1999 - The persistent and repetitive enactment of a behaviour pattern, which includes:
● Progression
● Pre-occupation with the activity
● Perceived loss of control
● Persistence, despite negative LT consequences
Griffiths, 1999:
, ● Progression
● Pre-occupation with the activity
● Perceived loss of control
● Persistence, despite negative LT consequences
● Perceived as mood modifiers
● Tolerance develops
● Perceived and real withdrawal symptoms
NEUROTRANSMITTERS
1. Neurotransmitters are released from the pre – synaptic membrane in response to an impulse
2. They cross the synaptic cleft and attach to post synaptic receptors.
3. This causes a response in this neurone.
4. The neurotransmitters are broken down in the synaptic cleft (by enzymes) and recycled or are
taken back into the synaptic knob and re-used (reuptake)
HEROIN RELATED CONCERNS
2012, In England and Wales: heroin/morphine related deaths = 579
(10% of alcohol mortality rate in UK!!!!!)
Tramadol and other opioids = 375
Total drug poisoning deaths = 2652
BUT = 52% of all fatal drug poisoning deaths (Office of National Statistics, 2012)
ALCOHOL RELATED CONCERNS
2011, 1.5% of all related deaths attributed to alcohol
5,792 deaths in UK alone in 2011
Overall cost to Government = £12.6 billion.
This estimate includes the cost of healthcare, crime and ASB, and loss of productivity in the
workplace due to absenteeism
(Office of National statistics, 2011)
Explanations for Nicotine Addiction
THE DOPAMINE EXPLANATION
It is thought that smoking/ingestion of nicotine can produce dopamine activity to spike, especially
through the ‘reward system’ pathways of the brain.
The Ventral Tegmental Area (VTA) is an area of the brain filled with dopamine-specialist neurons. This
area is associated with feelings of euphoria and can be triggered through smoking cigarettes,
producing a feeling of pleasure.
The explanation is that repeated usage of this system can lead to desensitisation, which then leads to
greater doses of drugs and eventually addiction
THE ROLE OF DOPAMINE
1. Nicotine stimulates specific acetylcholine (nicotinic acetylcholine receptors - NAcR) receptors
which increase alertness, memory function and learning.
2. This action causes a rise in dopamine activity in the ventral tegmental area (VTA): a critical
area in the brain's reward circuitry which is highly populated with NAcR. This is seen to
underline rewarding sensations linked to smoking.
3. The VTA activity caused by nicotine is then projected to the nucleus accumbens, a producer
of dopamine that is located deep in the mesolimbic dopamine pathway.
4. The nucleus accumbens is the primary reward centre in the brain and with increased activity
dopamine rises causing users to evaluate ‘smoking’ as very pleasurable, compelling further
use.
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