Drugs

 

• any man-made chemical taken into the body, (broadly) any chemical substance taken into the body;
• but this would include nutrients;
• chemicals which interfere with metabolism/physiology, ours or that of the pathogen;
• (narrowly) chemicals which interfere with nervous system/behaviour/brain/.perception/mental function;
• these are described as psychoactive;
• any chemical used in medicine;
• may be restricted to chemicals that cause harm/illicit chemicals/abused chemicals;

 

Distinguish between physical and psychological dependence on drugs

• dependence is inability to stop use/addiction;
• withdrawal symptoms if go without drug;
• g. morning shakes with alcohol/cold turkey with heroin

 

Physical 

• drug necessary for continued functioning of the body (metabolism in the body);
• prevents withdrawal/abstinence syndrome;
• withdrawal results in physical (and psychological)
• withdrawal symptoms e.g. opiates
• caused by drug replacing/imitating natural chemicals;

 

Psychological

• occurs when drug is needed as a compulsive desire to continue to take a drug;
• Reduces stress/anxiety/inhibitions;
• only emotional dependence/no physical dependency;
• withdrawal symptoms results in psychological symptoms
• changes in lifestyle and behaviour;

 

Withdrawal symptoms

• tremors;
• cravings/irritability/restlessness/anxiety;
• sweating;
• depression;
• sleep disturbance/insomnia;
• altered time perception;
• gastro interstitial problems/nausea/vomiting;

 

Drug tolerance and why it occurs with alcohol and heroin

• progressive decrease in body‘s response/effects become less intense with time/usage;
• user therefore uses larger and larger doses;

 

   Heroin

• binds to pain receptor molecules at synapses;
• mimics encephalins/natural neurotransmitters;
• body adapts to presence of heroin and tries to restore original state;
• more receptors made at post-synaptic membranes;
• so more heroin needed to saturate them/have same effect;

 

Alcohol

• alcohol tolerance due to liver adapting;
• by producing more enzymes that break down alcohol;
• oxidized by MEOS/microsomal ethanol oxidizing systems nerve cells in brain become less responsive;

 

How you might tell whether a drug is socially acceptable or not

• survey of people‘s attitudes to the drug
• legislation i.e. laws governing sale and use of drugs;
• g. banned by law;
• the number of people who use the drug/prevalence of drug taking;
• the number of deaths from illegal drugs;
• general acceptance or rejection of drug – takers;
• g. it is socially acceptable to drink alcohol
• but not acceptable to inject heroin;

 

Factors that contribute to drug dependence

• to experience its psychic effect;
• to avoid the discomfort caused by its absence/withdrawal;
• the drug (or one of it metabolites) has become necessary for the continued function of the body; – trying the drug out of curiosity;
• because of peer pressure/lack of self-identity;
• boredom

 

Why the use of heroin can result in damage to health

• use of unsterile needles to inject drug lead to blood poisoning/abscesses/skin infections at the sites of injection;
• shared needles may lead to transfer of infective hepatitis B/HIV/AIDS;
• long term use can lead to liver disease/failure;
• can lead to blood poisoning;
• transmission of disease e.g. HIV/AIDS/ hepatitis B;
• deficiency diseases/malnutrition due to reduced secretion of digestive juices/money spent on drugs rather than food/loss of appetite

• tend not to eat well therefore malnutrition;
• tend not to maintain standards of hygiene;
• may overdose as tolerance builds up;
• respiratory/ cardiac centres of the brain can be fatally depressed;
• constipation common;
• street heroin may be impure and mixed with harmful substances, this can cause blood poisoning/damage to blood vessels;
• damage to/collapse of blood vessels or veins due to injecting;
• tolerance leads to high doses/physical dependence/addiction is likely;
• associated life style has risks e.g. violence/crime/alcoholisms
• withdrawal/abstinence symptoms may lead to vomiting/choking/diarrhoea/dehydration/fever/high blood [pressure;
• users can become part of a drug subculture/loose contact with family and friends;
• damage to foetus;
• damage to mental health;

 

Metabolism of alcohol

• alcohol dehydrogenase;
• alcohol converted to acetaldehyde/ethanol;
• NAD – hydrogen carrier;
• ethane dehydrogenase;
• ethanol to acetic acid/acetate/ethanoic acid;
• acetate converted to acetyl coA;
• enters Krebs Cycle;
• respired to carbon dioxide and water;
• liver metabolises alcohol as an energy source rather than fat;
• catalase may also oxidize alcohol;
• MEOS used when blood alcohol concentration (BAC) is higher;

 

Long term consequences of alcohol consumption on the liver, brain and peripheral nervous system

Liver

• inflammation;
• scarring/fibrous tissue;
• cirrhosis/hepatitis/jaundice/cancer;
• fatty liver;
• compression of blood vessels in liver (blood forced from portal veins into veins from oesophagus and rectum);

 

Brain

• loss of short term memory
• impaired judgement;
• confusion/disorientation/anxiety/hallucinations;
• impaired motor control;
• dementia;
• sleep disturbance/reduced REM sleep;
• shrinkage of brain cells;
• by alcohol induced dehydration;
• inhibits secretion of AHD so kidneys remove more water than normal ;
• hypoxia – low blood oxygen causes death of brain cells;
• low blood glucose levels cause death of brain cells
• blockage of brain capillaries;
• loss of intellectual functions e.g. calculations, learning;
• Korsakoff‘s psychosis, leading to loss of short term memory and learning ;
• Wernicke‘s encephalopathy leading to comma, disturbance of speech/walking, confusion;
• Neglecting of diet leading to Vitamin B₁ deficiency – Leads to long term brain damage

 

Peripheral nervous system

• (poly) neuropathy (neurological disorder that occurs when many PNS throughout the body malfunction simultaneously);
• damage to sensory nerves;
• feeling cold, pains/cramps/numbness(partial/total lack of sensation)/tingling;
• starts in hands and spread to centre of body;
• damage to motor neurones;
• muscle wasting/weakness;
• damage to autonomic nerves;
• related to faintness/incontinence(involuntary urination/defecation)/impotence(powerlessness/feeble/weak)/blurred vision/poor control of gut;
• caused by Vitamin B₁/thiamine deficiency;
• poor diet/all or most energy needs from alcohol so no balanced diet; – damage to axons;

 

Short term effects of alcohol consumption on the brain

• depressant;
• effects depends on blood alcohol concentration;
• depresses brain function;
• by inhibiting reticular activating system (RAS);
• therefore activity of cerebral cortex
• intellectual faculties diminished;
• loss of coordination/judgement/control over fine movement;
• g. slurred speech/staggering walking;
• depression of respiratory centres/death;
• relaxed feeling/increased confidence/reduced tension;
• loss of inhibitions;
• slower reaction time;
• loss of balance;
• at higher levels, comma;

 

Social problems associated with heavy alcohol drinking

• personal relationship affected/considerable stress caused to the family;
• social isolation from friends/neighbours/embarrassment;
• violence in marriage + marital breakdown;
• correlated with wife battering (half husbands involved frequently drink);
• aggressiveness + destruction of property;
• crime as means to finance drinking;
• drink-driving + traffic accidents;
• neglect of food intake;
• frequent changes of jobs/loss of employment;
• uncontrollable anger;
• sexual assault;
• grandiose behaviour;
• young single women getting pregnant;
• conflict between parents affect children;
• sexual abuse of children;
• child neglect/children more likely to need child guidance/help from social services;
• children left unattended more likely to have accidents;
• poverty resulting from money spent on alcohol;
• poverty resulting from loss of job;
• poor health leading to loss of income/premature death;
• g. repossession of home, default on hire purchase/mortgage repayment;

 

Effects of heroin on the nervous system

• heroin is an opiate/depressant;
• does not stimulate vomit and nausea centres;
• psychoactive;
• binds (with high affinity and specificity) to pain receptors on the synapses;
• mimics encephalins;
• inhibits activities of the neurones concerned with pain;
• inhibits activities of cardiac and respiratory systems;
• gives a sense of warmth/rush;