Drugs, Brain and Behaviour

1. Drugs, Brain and Behaviour Dr E K Dordoye BSc, MBChB Post. Grad. Cert – HRM Resident – Faculty of Psychiatry, GCPS, WACP

2. Outline • Objectives • Functional Anatomy of the Brain • Brain and Behaviour • Different drugs of abuse • How drugs alter behaviour • Cause of drug abuse • Cycle of change

3. Objectives • Know gross anatomy of the brain • Know the various drugs of abuse • Understand the chemical basis of behaviour • Understand why drugs are abused

4. Anatomy of the Brain • The cerebrum • 2 cerebral hemispheres • Frontal lobe • Temporal lobe • Parietal lobe • Occipital lobe • Subcortical nuclei • Thalamus • Hypothalamus • Basal Ganaglia • Brain stem • Midbrain • Pons • Medulla oblongata • Cerebellum

5. Functional Anatomy • The cerebral Hemispheres are the seat of intelligence and where we take conscious decisions • The frontal lobe has the centres for voluntary movement and planning & execution of the plans i.e. Executive function • The temporal lobe has the language and hearing centres

6. Functional Anatomy • The parietal lobe receives and interprets sensory information • The occipital lobe receives and interprets visual stimuli

7. Functional Anatomy • The subcortical nuclei controls some of the involuntary actions and also serve to relay information to the cerebral hemispheres • The brainstem controls most of the automatic behaviours we exihibit such falling asleep and waking, breathing and walking smoothly without looking whether the floor is high or low • The cerebellum also fine tunes voluntary movements

8. Functional Anatomy • The limbic system comprise some of the sub-cortical nuclei and the frontal lobe • This system controls our emotions and feelings and also has the reward centre which controls our pleasure seeking behaviour • These are the centres which when activated by psychoactive drugs make an individual want to repeat that “behaviour” that activated the centre

9. Functional Anatomy • The brain’s basic units are the neurones by which the brain communicates with other parts of the body and brain itself. • Neurones do not communicate directly with another directly as they never touch each other but rather but via chemicals called neurotransmitters across the (synaptic) gaps between neurones

10. Functional Anatomy • Drugs or chemicals that can affect the function of neurotransmitters are called Psychoactive Substances • [psych = mind, substance = drug or chemical] • Since these chemicals are the means by which the brain interpret information coming to it, then an imbalance of these neurotransmitters will give “misinformation” to the brain and a consequent misintepretation

11. Functional Anatomy • Thus, neurotransmitter imbalance gives misinformation and the (mis)interpretation is the reason for symptoms of mental illness • Also, psychoactive substances, which are commonly abused, affect these neurotransmitters and hence consequent misinterpretation and behaviour

12. Functional Anatomy • Our behaviour is as a result of the interpretation our brains give to the environment • For instance, you may begin to remove your clothes now if you brain interprets that you are currently in your bathroom • In essence our behaviour is as a result of chemicals in our brains at any point in time and changing them will change our behaviours

13. Drugs of abuse • Alcohol • Beer, Stout (Guinness or Castle Milk Stout) • Palm wine, Pito • Gin e.g. Vodka, Schnnapps, akpeteshie • Nicotene • Stimulants • Cocaine • Amphetamines • Opioids • Codeine • Heroine • Morphine • Methadone • Cannabis or marijuana • Anxiolytics • Diazepam or Valium • Lorazepam or Ativan

14. Cause of Addiction • Alcohol and drug abuse is as a result of multiple interacting factors. • Initial experimentation of alcohol or drug is usually as a result of: • Alcohol or drug availability • Social acceptability e.g. Drinking at a social gathering like wedding, at death of a loved one etc • Peer pressure e.g smoking to join a cliché of friends

15. Cause of Addiction • The continual use of the substance of abuse will depend on: • Personality e.g. Impulsive individuals • Individual’s biology e.g. Genetic or Familial, especially in the male lineage • The effect of the drug e.g. Cocaine causes a lot of psychological craving and activate the limbic system like sex • Successful recovery from dependence • In all this learning plays a pivotal role in the maintenance of addiction

16. Cycle of Change