Drugs and Behaviour - Andy Parrott
Lecture 4: CNS Depressants – 11th October 2016
CNS Depressants: Overview
Alcohol as the archetypal CNS depressant
Consumption patterns
GABA receptor and neurochemical aspects
Behavioural effects
Drug tolerance, dependency, & alcoholism
Barbiturates: Lethal with alcohol & now withdrawn
Benzodiazepines: First developed in the 1960s and still widely used
Many other CNS depressants: not covered today
GABA MIGHT BE AN EXAM QUESTION!
Archetypal A typical instance of that class of items, alcohol is the classic drug
for the group of CNS depressants.
The main effect it has is on GABA. There are lots of drugs in this class but all have
slightly different effects. Alcohol is extremely damaging but as a drug it is one of
the safest. It is only very dangerous because it is widely used leading to large
numbers of alcohol related problems through society.
Alcohol consumption patterns
Consumed for +10,000 years. Used in most societies.
Babylonian laws to regulate drinking
, UK recommended maximum weekly intake: now 14units/week males, and
14 units/week females (was 21 for males).
Amoungst 16-24 year olds: 37% males & 23% females drink double this
level each week (Office of National Statistics)
Four million problem drinkers in UK. Likely to increase, more binge drinking,
happy hours, higher strength drinks.
Life stressors - heavy drinking becomes problematic.
Several members of the class may develop alcohol problems
Alcohol: Pharmacokinetic and other aspects
Water soluble, lipophobic, rapidly acting and metabolised. Repelled by
lipds/fats, all the fat in the body repels alcohol and so it is the non-fatty
tissues that absorb alcohol. This accounts for sex differences...
o Ethanol is infinitely soluble in water and, being slightly charged, it
readily forms equilibrium throughout water rich areas of the body
including the heart, kidneys, liver and nervous system. Therefore,
those tissues that are dense in cells and have a good blood supply,
receive alcohol more rapidly, including the brain. Conversely, those
structures that contain relatively little water such as bone and fat,
take longer to reach equilibrium and generally contain less alcohol.
Sex differences: Average female has lighter body mass and higher
proportion of body fat, thus higher BAC (blood alcohol concentration).
Vogel-Sprott (1984) females drank less to achieve similar BACs.
o Nolen (2004):
, Studied gender differences in risk factors and consequences
for alcohol use and problems.
Women drink less alcohol and have fewer alcohol-related
problems than men.
Women appear to be less likely than men to manifest certain
risk factors for alcohol use and problems and are more likely to
have certain protective factors against these problems: women
perceive greater social sanctions for drinking; women are less
likely to have characteristics associated with excessive drinking
including aggressiveness.
In addition, consequences of heavy alcohol use, or alcohol use
disorders, appear to be more negative for women than men in
some domains: women suffer alcohol-related physical illnesses
at lower levels of exposure to alcohol than men, and some
studies suggest women suffer more cognitive and motor
impairment due to alcohol than men; women may be more
likely than men to suffer physical harm and sexual assault
when they are using alcohol; heavy alcohol use in women is
associated with a range of reproductive problems.
Calories: Can survive on alcohol diet... but vitamin deficiency as a result of
poor diet through drinking alcohol can lead to Korsakoff Psychosis... brain
lesions and very poor memory. Leads to brain lesions in hippocampus and
other basic brain areas. Chronic memory disorder caused by a severe
deficiency of thiamine (Vitamin B-1). Thiamine (vitamin B-1) helps brain
cells produce energy from sugar. When levels fall too low, brain cells
Lecture 4: CNS Depressants – 11th October 2016
CNS Depressants: Overview
Alcohol as the archetypal CNS depressant
Consumption patterns
GABA receptor and neurochemical aspects
Behavioural effects
Drug tolerance, dependency, & alcoholism
Barbiturates: Lethal with alcohol & now withdrawn
Benzodiazepines: First developed in the 1960s and still widely used
Many other CNS depressants: not covered today
GABA MIGHT BE AN EXAM QUESTION!
Archetypal A typical instance of that class of items, alcohol is the classic drug
for the group of CNS depressants.
The main effect it has is on GABA. There are lots of drugs in this class but all have
slightly different effects. Alcohol is extremely damaging but as a drug it is one of
the safest. It is only very dangerous because it is widely used leading to large
numbers of alcohol related problems through society.
Alcohol consumption patterns
Consumed for +10,000 years. Used in most societies.
Babylonian laws to regulate drinking
, UK recommended maximum weekly intake: now 14units/week males, and
14 units/week females (was 21 for males).
Amoungst 16-24 year olds: 37% males & 23% females drink double this
level each week (Office of National Statistics)
Four million problem drinkers in UK. Likely to increase, more binge drinking,
happy hours, higher strength drinks.
Life stressors - heavy drinking becomes problematic.
Several members of the class may develop alcohol problems
Alcohol: Pharmacokinetic and other aspects
Water soluble, lipophobic, rapidly acting and metabolised. Repelled by
lipds/fats, all the fat in the body repels alcohol and so it is the non-fatty
tissues that absorb alcohol. This accounts for sex differences...
o Ethanol is infinitely soluble in water and, being slightly charged, it
readily forms equilibrium throughout water rich areas of the body
including the heart, kidneys, liver and nervous system. Therefore,
those tissues that are dense in cells and have a good blood supply,
receive alcohol more rapidly, including the brain. Conversely, those
structures that contain relatively little water such as bone and fat,
take longer to reach equilibrium and generally contain less alcohol.
Sex differences: Average female has lighter body mass and higher
proportion of body fat, thus higher BAC (blood alcohol concentration).
Vogel-Sprott (1984) females drank less to achieve similar BACs.
o Nolen (2004):
, Studied gender differences in risk factors and consequences
for alcohol use and problems.
Women drink less alcohol and have fewer alcohol-related
problems than men.
Women appear to be less likely than men to manifest certain
risk factors for alcohol use and problems and are more likely to
have certain protective factors against these problems: women
perceive greater social sanctions for drinking; women are less
likely to have characteristics associated with excessive drinking
including aggressiveness.
In addition, consequences of heavy alcohol use, or alcohol use
disorders, appear to be more negative for women than men in
some domains: women suffer alcohol-related physical illnesses
at lower levels of exposure to alcohol than men, and some
studies suggest women suffer more cognitive and motor
impairment due to alcohol than men; women may be more
likely than men to suffer physical harm and sexual assault
when they are using alcohol; heavy alcohol use in women is
associated with a range of reproductive problems.
Calories: Can survive on alcohol diet... but vitamin deficiency as a result of
poor diet through drinking alcohol can lead to Korsakoff Psychosis... brain
lesions and very poor memory. Leads to brain lesions in hippocampus and
other basic brain areas. Chronic memory disorder caused by a severe
deficiency of thiamine (Vitamin B-1). Thiamine (vitamin B-1) helps brain
cells produce energy from sugar. When levels fall too low, brain cells
