18: Affective Disorders Flashcards
Schizophrenia means…
The splitting of psychic functions.
Schizophrenia affects…
1% of all individuals.
Positive symptoms
Excessive or warped normal functions.
Negative symptoms
Reduced or absent normal functions.
Positive symptoms include (4)…
Delusions, hallucinations, inappropriate affect, incoherent speech/thought, odd behaviour.
Negative symptoms include (4)…
Affective flattening, inability to process language and speech, loss of willpower or motivation, anhedonia.
Minimum for diagnosis of schizophrenia…
Recurrence of any two symptoms for 1 month, or a very bizarre occurence of one symptom.
Probability of schizophrenia occuring in close relative…
10% regardless of upbringing.
First antischizophrenic drug
Chlorpromazine.
Reserpine is no longer used because…
It produces a dangerous decline in blood pressure.
Dopamine theory of schizophrenia
Excess of dopaminergic transmission. In particular, high levels of activity at D2 receptors.
Reserpine treats schizophrenia by…
Breaking down synaptic vesicles which store dopamine and other monoamines.
Amphetamines and coke trigger schizophrenic episodes by…
Increasing extracellular levels of dopomine and other monoamines in brain.
Chlorpromazine intervenes with dopaminergic transmission by…
Binding to dopamine receptors and blocking dopamine from activating them.
Reserpine intervenes with dopaminergic transmission by…
Depleting the brain of dopamine.
Lack of activity at postsynaptic dopamine receptors led to…
Feedback being sent demanding for presynaptic cells to increase dopamine transmission.
Haloperidol
Has a low affinity for dopamine receptors because it selectively binds to D2 class of receptors, but not D1.
Receptor subtypes (dopamine)
Dopamine binds to up to 5 receptor subtypes, explaining unequal affinities for different antischizophrenic drugs.
The phenothiazines
A chemical class of receptor subtypes that chlorpromazine belongs to (D1 & D2).
The butyrophenones
A chemical class of receptor subtypes that haliperidol belongs to (D2 but not D1).
Other neurotransmitters linked to schizophrenia (2)…
Glutamate and serotonin.
What effects do LSD and PCP produce?
Produce hallucinogenic effects akin to serotonergic and glutaminergic transmission.
Clozapine
A type of atypical neuroleptic with an affinity for D1, D4, and serotonin receptors - but only a small one for D2. Contra!
Schizophrenic brain damage occurs in…
Both grey and white matter, and particularly within the temporal lobes.
Dopamine theory cannot account for schizophrenic brain damage because…
Little evidence of specific structural damage to dopaminergic circuits, and cannot account for the typically diffuse patterns of brain damage.
Neuroleptics are more effective at treating…
Positive rather than negative symptoms of schizophrenia.
Side effects of typical neuroleptics…
Motor disturbances.
Side effects of atypical neuroleptics…
Diabetes, weight gain, difficulties with fat regulation. To do with influence on histamine?
Anhedonia
Loss of ability to experience pleasure.
Affective disorder refers to…
Any psychiatric disorder characterised by disturbances of mood/emotion. A.K.A mood disorders.
Women are twice as likely as men to be diagnosed with…
Unipolar depression.
In adults, affective disorders are associated with…
Heart disease. In women, bone loss.
Concordance rates for affective disorders…
MZ: 60%, DZ: 15%.
Stress on depression…
Little evidence that it increases onset chances; rather, it triggers those already suffering, and is more likely to induce PTSD.
Four major drug classes for treating affective disorders (MTSM)…
Monoamine Oxidase Inhibitors, Tricyclic Antidepressants, Selective Monoamine-Reuptake Inhibitors, Mood Disorders.
Monoamine Oxidase Inhibitors…
Such as iproniazid. Increases monoamine activity levels via inhibition of monoamine oxidase (MAO), an enzyme involved in degradation of monoamine transmitters.
MAO inhibitor side effects…
‘Cheese effect’ - contains tyramine, a powerful blood pressure elevator. This is usually metabolised by MAO.
Tricyclic Antidepressants…
Named due to three-ring chemical atomic structure. Block reuptake of serotonin and norepinephrine, and are safer than MAO inhibitors. Imipramine is an example drug.
Selective Monoamine-Reuptake Inhibitors…
SSRIs, such as Prozac. Equally effective as imipramine, but has fewer side effects and more widespread application.
Mood Stabilisers…
E.g. lithium. Unlike antidepressants, don’t treat by inducing mania symptoms in depressed patients.
A meta-analysis by Kirsch et al (2008) found…
That placebos were 82% as effective as actual antidepressants.
Best for treating mania (2) and depression (2)…
Lithium and carbamazepine for the former, mania and lamotrigine for the latter.
Two brain structures found abnormal in affective disorder patients…
Amydala and anterior cingulate cortex. Loss of tissue.
Monoamine Theory of Depression…
Depression associated with underactivity at serotonergic and noradrenergic synapses. Deficit in monoamine release which leads to up-regulation.
Diathesis-Stress Model of Depression
Exposure to stress in gene-susceptible individuals early in life induces a permanent oversensitisation to stressors in later life.
Brain stimulation to treat depression…
Electrically stimulate white matter of anterior cingulate gyrus.
Sleep deprivation on depression…
More than 50% of patients display dramatic improvements after one night of sleep deprivation.
Anxiety
Chronic fear that persists even when direct threat is not present.
Two classes of drugs effective for treating anxiety disorders…
Benzodiazepines and serotonin agonists.
3 forms of benzodiazepine prescription…
Hypnotics, anticonvulsants (a.k.a anti-epileptics), and muscle relaxants.
6 side effects of benzodiazepines…
Sedation, ataxia, tremor, nausea, addiction, and withdrawl leading to rebound.
Molecular workings of benzodiazepies…
GABAa agonists. By binding to GABAa receptors which increases the binding of GABA molecules to the receptor.
Chlordiazepoxide (Librium) and diazepam (Valium) are…
Benzodiazepines.
Molecular workings of serotonin agonists…
Selective agonist effects at one subtype of serotonin receptor, 5-HT(1A) - they are SSRIs.
Side effects of serotonin agonists…
Manages to produce anxiolytic effects without side effects of benzodiazepines.
Neural theories for anxiety disorders…
Focus on the amygdala due to its role in fear and defensive behaviour. Also has a concentration of GABAa receptors.
Concordance rates for Tourette’s Syndrome…
MZ: 55% DZ: 8%
Abnormailities in the brain of Tourette’s patients…
Almost always observed in the basal ganglia, and secondarily in the limbic and association cortices.
Tics are treated using…
Neuroleptics. These are D2 blockers.
Current hypothesis for Tourette’s Syndrome…
It is a neurodevelopmental disorder involving an excess of dopaminergic projections between striatum and associated limbic cortex.
Brown (1993) found that ??% of patients with severe stress experience had sought treatment, compared to ??% of control patients.
84, 32.
The drug imipramine is a…
Tricyclic antidepressant.
