Fatal familial insomnia (FFI) is characterized by minimal spongiform change, but notable thalamic atrophy and astrogliosis. Diagnosis of FFI relies heavily on immunohistochemistry and genotyping. In contrast, spongiform change is a hallmark of CJD and Kuru. The majority of CJD cases (85%) are sporadic, while only a small percentage are caused by consuming contaminated food (variant CJD of vCJD).

SNRIs include duloxetine and venlafaxine.

Antidepressants: Mechanism of Action

Antidepressants are a class of drugs used to treat depression and other mood disorders. The mechanism of action of antidepressants varies depending on the specific drug. Here are some examples:

Mirtazapine is a noradrenaline and serotonin specific antidepressant (NaSSa). It works by blocking certain receptors in the brain, including 5HT-1, 5HT-2, 5HT-3, and H1 receptors. It also acts as a presynaptic alpha 2 antagonist, which stimulates the release of noradrenaline and serotonin.

Venlafaxine and duloxetine are both serotonin and noradrenaline reuptake inhibitors (SNRIs). They work by blocking the reuptake of these neurotransmitters, which increases their availability in the brain.

Reboxetine is a noradrenaline reuptake inhibitor (NRI). It works by blocking the reuptake of noradrenaline, which increases its availability in the brain.

Bupropion is a noradrenaline and dopamine reuptake inhibitor (NDRI). It works by blocking the reuptake of these neurotransmitters, which increases their availability in the brain.

Trazodone is a weak serotonin reuptake inhibitor (SRI) and 5HT agonist. It works by increasing the availability of serotonin in the brain.

St John’s Wort is a natural supplement that has been used to treat depression. It has a weak monoamine oxidase inhibitor (MAOI) effect and a weak SNRI effect.

In summary, antidepressants work by increasing the availability of certain neurotransmitters in the brain, such as serotonin, noradrenaline, and dopamine. The specific mechanism of action varies depending on the drug.

Trait Theory: Understanding Personality Traits

Trait theory is a psychological approach that seeks to understand personality by identifying and categorizing specific traits. The theory was first introduced by Gordon Allport, who classified personality traits into three levels.

At the highest level, we have cardinal traits. These are traits that are so pervasive that they dominate a person’s behavior and activities. Only a few people possess cardinal traits, but for those who do, these traits are the ruling force of their personality. Cardinal traits are usually evident to most people who know the individual.

The second level of traits is central traits. These are easily detected characteristics within a person, traits that all people have a certain number of, usually around five to ten on average. Central traits are the building blocks of personality and help to define a person’s overall character.

Finally, we have secondary traits. These are less evident and only manifest in select circumstances. They are not as important as central of cardinal traits, but they still play a role in shaping a person’s behavior and personality.

Overall, trait theory provides a useful framework for understanding personality and how it develops over time. By identifying and categorizing specific traits, psychologists can gain insights into why people behave the way they do and how they can change their behavior to achieve their goals.

Anorexia nervosa and bulimia nervosa share similar clinical syndromes, and individuals with eating disorders may transition between the two disorders multiple times. The bulimic subtype of anorexia nervosa involves binge episodes. Anorexia nervosa is more prevalent in females, with a female-to-male ratio of 10:1. Endocrine abnormalities associated with anorexia nervosa include amenorrhea, low levels of gonadotropins (LH and FSH), low levels of estrogen and progesterone, low levels of triiodothyronine, high levels of cortisol, high levels of fasting growth hormone, and irregular vasopressin release.

Given the medial temporal lobe atrophy commonly observed in Alzheimer’s disease, a reduction in perfusion of the temporal lobe would be anticipated.

Alzheimer’s disease can be differentiated from healthy older individuals by using SPECT imaging to detect temporal and parietal hypoperfusion, according to studies such as one conducted by W. Jagust in 2001. Additionally, SPECT imaging has proven to be a useful tool in distinguishing between Alzheimer’s disease and Lewy body dementia, as demonstrated in a study by Vaamonde-Gamo in 2005. The image provided shows a SPECT scan of a patient with Alzheimer’s disease compared to one with Lewy body dementia, with the latter showing lower perfusion in the occipital cortex and the former showing lower perfusion in medial temporal areas.

Ganser syndrome is characterized by approximate answers, clouding of consciousness, somatic conversion features, and pseudohallucinations. It is controversially classified as a reactive psychosis, with stressful life events as a possible trigger. Pseudologia fantastica, of pathological lying, involves grandiose and extreme untruthful statements that may be believed by the individual, often associated with personality disorders such as histrionic of dissocial and precipitated by major life crises. Cryptomnesia involves falsely recalling an idea, thought, of song as new and original. Confabulation is the falsification of memory in clear consciousness, often used to cover up memory gaps. Dissociative fugue state involves narrowing of consciousness, wandering away from normal surroundings, and subsequent amnesia, with the individual appearing to be in good contact with their environment and maintaining basic self-care.

First degree relatives of patients with Alzheimer’s disease (AD) have a threefold higher risk of developing the disease compared to non-relatives. The most significant genetic risk factor for AD is the apolipoprotein E (apo E) gene, located on chromosome 19q, which has three codominant alleles: e2, e3, and e4. The e4 allele, which is overrepresented, and the e2 allele, which is underrepresented, are associated with AD. In Caucasians, individuals who are homozygous for e4 have 14.9 times greater odds of developing AD, while those who are heterozygous for e3/e4 have 3.2 times greater odds compared to those who are homozygous for e3. Additionally, e4 homozygotes tend to develop AD at an earlier age, by approximately two decades.

Excitatory neurotransmitters include glutamate, histamine, acetylcholine, and noradrenaline, as they increase ion flow and the likelihood of action potential in neurons. However, GABA functions as an inhibitory neurotransmitter, reducing ion flow and decreasing the probability of action potential.

Understanding Prosody and Aprosodias

Prosody refers to the emotional tone of language, which is conveyed through the melodious quality and inflections in the voice. It is affected by various psychiatric and neuropsychiatric illnesses, and disorders in the ability to express of understand the emotional overlay of speech are called aprosodias. Aprosodias are typically caused by dysfunction in areas of the non-dominant hemisphere, usually the right side of the brain.

Executive aprosody, which is the ability to express emotions in speech, can be tested by asking the patient to repeat a neutral sentence with different emotions. It is affected by lesions of the right premotor cortex of the basal ganglia. On the other hand, receptive aprosody, which is the ability to understand emotions in speech, can be tested by asking the patient to identify the emotion conveyed in a neutral sentence with different emotional inflections. It is affected by lesions of the posterior superior right temporal lobe.

Abnormalities of prosody are not specific to any particular disorder, but patients with severe depression, schizophrenia, and pervasive developmental disorders often present with characteristic abnormalities of prosody. For instance, severely depressed patients may have a monotonous, affect-neutral pattern of speech, while patients with schizophrenia may present with abnormal modulation of emphasis and volume of unusual accents. Patients with autism and Asperger’s disorder may have speech patterns that are monotonous, robotic, of singsong in quality.

Lithium – Pharmacology

Pharmacokinetics:
Lithium salts are rapidly absorbed following oral administration and are almost exclusively excreted by the kidneys unchanged. Blood samples for lithium should be taken 12 hours post-dose.

Ebstein’s:
Ebstein’s anomaly is a congenital malformation consisting of a prolapse of the tricuspid valve into the right ventricle. It occurs in 1:20,000 of the general population. Initial data suggested it was more common in those using lithium but this had not held to be true.

Contraindications:
Addison’s disease, Brugada syndrome, cardiac disease associated with rhythm disorders, clinically significant renal impairment, untreated of untreatable hypothyroidism, low sodium levels.

Side-effects:
Common side effects include nausea, tremor, polyuria/polydipsia, rash/dermatitis, blurred vision, dizziness, decreased appetite, drowsiness, metallic taste, and diarrhea. Side-effects are often dose-related.

Long-term use is associated with hypothyroidism, hyperthyroidism, hypercalcemia/hyperparathyroidism, irreversible nephrogenic diabetes insipidus, and reduced GFR.

Lithium-induced diabetes insipidus:
Treatment options include stopping lithium (if feasible), keeping levels within 0.4-0.8 mmol/L, once-daily dose of the drug taken at bedtime, amiloride, thiazide diuretics, indomethacin, and desmopressin.

Toxicity:
Lithium salts have a narrow therapeutic/toxic ratio. Risk factors for lithium toxicity include drugs altering renal function, decreased circulating volume, infections, fever, decreased oral intake of water, renal insufficiency, and nephrogenic diabetes insipidus. Features of lithium toxicity include GI symptoms and neuro symptoms.

Pre-prescribing:
Before prescribing lithium, renal function, cardiac function, thyroid function, FBC, and BMI should be checked. Women of childbearing age should be advised regarding contraception, and information about toxicity should be provided.

Monitoring:
Lithium blood levels should be checked weekly until stable, and then every 3-6 months once stable. Thyroid and renal function should be checked every 6 months. Patients should be issued with an information booklet, alert card, and record book.