week 10 Psychological disorders Flashcards
List the various diagnostic criteria for major depression. Note that there are many and diverse symptoms.
ongoing for minimum 2 weeks, reduced functioning cf previous, either depressed mood or loss of pleasure for most of the 2 weeks, possible weight loss/gain, possible insomnia/hypersomnia.
Briefly point out evidence of a genetic link.
moderate genetic link for major depression.Likely multiple genes and they vary with ethnicity. Possibly also different forms ie earlier and later onset might be different entities.
Environmental influence also.
Note any gross neurological correlates of depression (decreased activity in left hemisphere; increased activity in right prefrontal cortex).
Depression correlates with increased activity in the right prefrontal cortex-this seems stable over years.
Most people, given a verbal task to consider,gaze right, suggesting left hemisphere dominance. Most with depression with gaze left.
Discuss evidence of the importance of monoamine neurotransmitters (Serotonin and Dopamine)
In Depression there are low levels of norepinephrin, and/or serotonin. Most people with depression have lower than normal levels of Brain-derived neurotrophic factor (correlated to smaller hippocampus, impaired learning ).Dopamine is a mood enhancer and not part of depression but might be linked with how drugs affect.
List and Understand the main types of drug therapies and briefly Understand their mode of action (i.e., some drugs block reuptake of certain neurotransmitters; other drugs block the actions of enzymes on these neurotransmitters, etc.). The drugs to focus on are the: tricyclics, MAOIs, SSRIs.
Monoamine Oxidase Inhibitors (MAOI’s);blocks monoamine oxidase
(monoamine oxidase is a presynaptic enzyme which metabolises catacholamines/serotonin/nor-epinephrin/dopamine into inactive metabolites.) Thus pre-synaptic terminal has more of these neurotransmitters for release. One of the earliest anti-depressants. No longer first choice tx. Increases bp and must avoid tyramine-containing food (cheese,raisins). eg Phenelzine.
Tricyclic Antidepressants: blocks transporter proteins from being able to re-take serotonin/dopamine/nor-epinephrine into the pre-synaptic neuron. This prolongs the effect of neurotransmitter at the synaptic cleft. Also often block histamine receptors (therefore drowsiness), sodium channels (may lead to heart arrythmia)and acetylcholine receptors (may lead to dry mouth and urinary retention).
Selective Serotonin Reuptake Inhibitors (SSRI’s);similar to tricyclic antidepressant but specific for blocking serotonin transport, therefore more available at synapse. Less side effects than tricyclic but approx same effectiveness. eg Fluoxetine.
Serotonin Nor-epinephrine Reuptake inhibitor (SNRI’s)block re-uptake of serotin and epi-nephrine. These also improve some aspects of memory. eg Venlafaxine.
Atypical Antidepressants: many different types eg Bupropion which inhibits re-uptake of dopamine and nor-epinephrine but has no effect on serotonin.
Most patients now tend to be on a couple of medications but not really proven more effective than monotherapy (although possibly means lower doses of each and less side effects).
St John’s wort; herb of dubious effect and unregulated in US (=variable purity).
What does ECT involve, and what sorts of successes have been obtained with this method of treatment?
Electro convulsive therapy. Induce a seizure under ga. Last resort tx (ie other tx have failed). 70% effective but does have a death rate of 1 in 1000.
What is bipolar disorder, and how can it be distinguished from unipolar depression?
Periods of mania in between bouts of depression
Distinguish between bipolar I and II.
Bipolar 1: Full blown mania episodes
Bipolar 2: episodes of hypomania.. Both cycle between that and depression.
Briefly point out evidence of a genetic link
Moderate level genetic influence. Many possible genes involved. Shared genetic risk of depression, bipolar and schizophrenia (same potential genes may be involved).
Discuss evidence of the importance of lithium salts in treating bipolar disorder chemically.
Most common tx for the bipolar part. Does not treat depression component. Is a mood stabiliser. Some cells of the hippocampus (which can form new cells throughout life) are hyperexcitable in bipolars , and lithium acts to relieve this. Lithium is toxic at high doses.
Also sometimes use anticonvulsants and or antipsychotics. Use antidepressives for the depression component.
What is seasonal affective disorder and in which sorts of environmental situations does it occur? Understand successful treatments of this disorder using the application of bright lights.
Seasonal affective Disorder is depression ocurring just during a specific season (Winter). Tends to occur near the poles. Unheard of in tropics. Patients have Phase-delayed circadian rhythm. Many have a genetic mutation in a gene involved in circadian rhythm regulation. Treat with very bright lights for a few hours in morning. This tx also helps for regular depression too.
List and Understand the symptoms of schizophrenia, distinguishing between positive and negative symptoms (provide examples of symptoms of each type).
Hallucinations, delusions, flattened emotion, disorganized speech, disorganized movements. “Positive” symptom=increased/additional cf normal eg hallucination. “Negative” = less than normal eg flattened emotion. Disorganized sometimes classified as negative, and sometimes as disorganised.
What are the main drugs used to treat schizophrenia?
Antipsychotics (=neuroleptics) are the main therapy. Phenothiazines (eg Chlorpromazine) and Butyrophenones eg Haloperidol. Tends to block Dopamine type 2 receptors at synapses, thus decreasing the effect of dopamine. May cause irreparable tardive dyskinesis.
Second generation antipsychotic drugs (=atypical antipsychotics). Have less effect on dopamine receptors but increased antagonism of serotonin 5-ht receptors. Also increase the release of gl;utamate. Less risk of tardive dyskinesis but have other side effects such as weight gain and reduced immune system. eg Clozapine, risperidone.
Both types probably comparable with effectiveness, just have different sid effects, and one class might work better for 1 patient than other.
What is meant by the term ‘differential diagnosis”? List some psychological disorders with similar symptoms to schizophrenia.
= Signs might also fit with another disease such as…..
ddx psychotic episode due to drugs, Huntington’s, brain damage/lesion, nutritional issue eg vitamin c deficiency, lactose or gluten intolerance can also cause hallucinations etc.
Note the evidence pointing to a strong genetic link in schizophrenia. Explain why it has been difficult to find a genetic marker(s) for the disorder.
Increased risk of schizophrenia if birth parent has and brought up in stressful environment. Increased risk amongst relatives. Difficult to find genetic markers as many genes likely involved, environment also plays a part and schizophrenics on average tend to have less offspring. Also increased risk if perinatal issue.
