Neurotransmitters and their Effects

1. Neurotransmitters and their Effects • Neurotransmitters have been studied quite a bit in relation to psychology and human behavior. • What we have found is that several neurotransmitters play a role in the way we behave, learn, the way we feel, and sleep. • And, some play a role in mental illnesses. The following are those neurotransmitters which play a significant role in our mental health.

2. Neurotransmitters and their Effects • Please note that these associations are merely correlations, and do not necessarily demonstrate any cause and effect relationship. • We don’t know what other variables may be affecting both the neurotransmitter and the mental illness, and we don’t know if the change in the neurotransmitter causes the illness, or the illness causes the change in the neurotransmitter

3. Using one or more examples, explain the effects of neurotransmission on behavior The effect of serotonin on human behavior • Serotonin is a neurotransmitter and it has several functions in humans: • the regulation of intestinal movements, • the regulation of mood, appetite, sleep, muscle contraction, • cognitive functions including memory and learning.

4. The effect of serotonin on human behavior • Research with non human animals suggests serotonin appear to have a role in social behavior: • Kravitz (1988) injected lobsters with serotonin and found that they behaved like a dominant animal • With humans, a great deal of research has been done on the connection between serotonin and depression

5. The Monoamine hypothesis • The monoamine hypothesis proposes that low levels of the neurotransmitters serotonin,norepinephrine and dopamine in the synaptic gap between neurons in the brain, are associated with depression (Barlow, 1995) • Because of this, psychoactive drugs have been developed to increase the effect peoples behavior by increasing amount of these monoamines at the synapse, these are called SSRI’s,MAOI’s & TCA’s they have been very successful

6. Depression - One of most common reason for going to the doctor 20% lifetime risk. Clinical Characteristics of Unipolar Depression

7. Check your understanding… • Explain what SSRI’s are and exactly how they work

8. Quick quiz: • What is at the end of each axon? • Neurotransmitters need to cross the synaptic _________ and bind onto receptor cites. • Give four clinical characteristics of depression • What did Kravitz (1988) find out about serotonin? • What is serotonin? What role does it play in humans and animals? • What is the monoamine hypothesis? • What does SSRI stand for? • How do these work?

9. In pairs, read and explain your section: • TCA’s • MAOIs • SSRI’s • Effective in reducing symptoms • Comparing effectiveness and side effects of TCAs and MAOIs • Prozac, the wonder drug? • Use with older and younger people

10. Anti-depressant drugs Most common and popular drug treatment for unipolar depression, • These drugs are designed to enhance the mood of people with depression • They effect the availability of serotonin and nor adrenaline which are neurotransmitters implicated in depression, there are three main types: • Monoamine-oxidize inhibitors (MAOIs) • Tricyclics (TCAs) • Selective serotonin re-uptake inhibitors (SSRIs)

11. The different types of antidepressants • Monoamine-oxidize inhibitors (MAOIs) • This antidepressant was discovered by accident when a new drug for TB was found to induce euphoria. • MAOIs work by blocking the action of the enzyme that breaks down nor-adrenaline and serotonin, so this increases the availability of these neurotransmitters in the nervous system • Tricyclics (TCAs) • These work in a similar way to MAOIs but are milder antidepressant, although they are slower in acting, the have fewer severe side effects • Selective serotonin re-uptake inhibitors (SSRIs) • SSRIs such as Prozac inhibit the re-uptake of serotonin at the synapse and thus make more of the neurotransmitter available. • Recently the natural herb hypericum, commonly known as St. Johns Wort has been found in clinical trials to have anti-depressant qualities with very few side effects. It is thought that the herb alters serotonin function in some way.

12. Evaluation: The use of antidepressants • Effective in reducing symptoms • Comparing effectiveness and side effects of TCAs and MAOIs • Prozac, the wonder drug? • Use with older and younger people

13. Evaluation: The use of antidepressants • Effective in reducing symptoms – Antidepressents have been found to be effective in reducing symptoms of severe depression in around 65% to 75% of cases, compared to 33% for placebos (Prien et al, 1988) • Comparing effectiveness and side effects of TCAs and MAOIs – Spiegel (1989) found that around 65% of depressed patients improved with tricyclics (TCAs), although there are potential side effects, the most serious being cardiac problems • MAOIs are equally effective, but require dietary restriction and can react dangerously with other drugs such as cold remedies. Tricyclics are prescribed more often because they are milder and have less severe side effects

14. Evaluation: The use of antidepressants • Prozac, the wonder drug? – Prozac (an SSRI) was hailed the ‘wonder drug’ when it was first introduced in the late 1980s and it is currently the most frequently prescribed of all anti depressants. However, it has recently become a media target because of many anecdotal reports of serious side effects, including a preoccupation with violence and suicide in users (Steiner, 1991) • Use with older and younger people – antidepressants are less effective with children, but very effective with older people, although with more side effects

15. Quick quiz • What is serotonin? • What is the monoamine hypothesis? • What does SSRI stand for? How do they work? • What does MAOI stand for? How to they work? • What is the most commonly prescribed of all antidepressants? • How effective are antidepressants in reducing the symptoms of depression? • What are the strengths and weaknesses of drug treatments? • With which age group are antidepressants more effective, older or younger people?

16. Quick quiz • What is serotonin? • What is the monoamine hypothesis? • What does SSRI stand for? How do they work? • What does MAOI stand for? How to they work? • What is the most commonly prescribed of all antidepressants? • How effective are antidepressants in reducing the symptoms of depression? • What are the strengths and weaknesses of drug treatments? • With which age group are antidepressants more effective, older or younger people?

17. SAQ Planning activity • Using one or more examples, describe the effects of neurotransmission on behavior • Using one or more examples, explain the effects of neurotransmission on behavior • Using one or more examples, analyze the effects of neurotransmission on behavior Make a plan in groups, and then one person type up the notes, and Attach it on the wiki – you will do one of these SAQ’s in class