Hardy-Weinberg Principle and Allele Frequency

Allele frequency refers to the proportion of a population that carries a specific variant at a particular gene locus. It can be calculated by dividing the number of individual alleles of a certain type by the total number of alleles in a population. The Hardy-Weinberg Principle states that both allele and genotype frequencies in a population remain constant from generation to generation unless specific disturbing influences are introduced. To remain in equilibrium, five conditions must be met, including no mutations, no gene flow, random mating, a sufficiently large population, and no natural selection. The Hardy-Weinberg Equation is used to predict the frequency of alleles in a population, and it can be used to estimate the carrier frequency of genetic diseases. For example, if the incidence of PKU is one in 10,000 babies, then the carrier frequency in the general population is 1/50. Couples with a previous child with PKU have a 25% chance of having another affected child.

Discontinuation syndrome of selective serotonin reuptake inhibitors may manifest with diverse symptoms such as abdominal pain, vomiting, and diarrhea.

Antidepressants can cause discontinuation symptoms when patients stop taking them, regardless of the type of antidepressant. These symptoms usually occur within 5 days of stopping the medication and can last up to 3 weeks. Symptoms include flu-like symptoms, dizziness, insomnia, vivid dreams, irritability, crying spells, and sensory symptoms. SSRIs and related drugs with short half-lives, such as paroxetine and venlafaxine, are particularly associated with discontinuation symptoms. Tapering antidepressants at the end of treatment is recommended to prevent these symptoms. TCAs and MAOIs are also associated with discontinuation symptoms, with amitriptyline and imipramine being the most common TCAs and all MAOIs being associated with prominent discontinuation symptoms. Patients at highest risk for discontinuation symptoms include those on antidepressants with shorter half-lives, those who have been taking antidepressants for 8 weeks of longer, those using higher doses, younger people, and those who have experienced discontinuation symptoms before. Agomelatine is not associated with any discontinuation syndrome. If a discontinuation reaction occurs, restarting the antidepressant of switching to an alternative with a longer half-life and tapering more slowly may be necessary. Explanation and reassurance are often sufficient for mild symptoms. These guidelines are based on the Maudsley Guidelines 14th Edition and a study by Tint (2008).

The absence of a halo distinguishes the Lewy bodies found in the brainstem from those found in the cortex. These bodies consist of alpha-synuclein protein, along with other proteins like ubiquitin, neurofilament protein, and alpha B crystallin. Additionally, they may contain tau proteins and are sometimes encircled by neurofibrillary tangles.

Lewy body dementia is a neurodegenerative disorder that is characterized by both macroscopic and microscopic changes in the brain. Macroscopically, there is cerebral atrophy, but it is less marked than in Alzheimer’s disease, and the brain weight is usually in the normal range. There is also pallor of the substantia nigra and the locus coeruleus, which are regions of the brain that produce dopamine and norepinephrine, respectively.

Microscopically, Lewy body dementia is characterized by the presence of intracellular protein accumulations called Lewy bodies. The major component of a Lewy body is alpha synuclein, and as they grow, they start to draw in other proteins such as ubiquitin. Lewy bodies are also found in Alzheimer’s disease, but they tend to be in the amygdala. They can also be found in healthy individuals, although it has been suggested that these may be pre-clinical cases of dementia with Lewy bodies. Lewy bodies are also found in other neurodegenerative disorders such as progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy.

In Lewy body dementia, Lewy bodies are mainly found within the brainstem, but they are also found in non-brainstem regions such as the amygdaloid nucleus, parahippocampal gyrus, cingulate cortex, and cerebral neocortex. Classic brainstem Lewy bodies are spherical intraneuronal cytoplasmic inclusions, characterized by hyaline eosinophilic cores, concentric lamellar bands, narrow pale halos, and immunoreactivity for alpha synuclein and ubiquitin. In contrast, cortical Lewy bodies typically lack a halo.

Most brains with Lewy body dementia also show some plaques and tangles, although in most instances, the lesions are not nearly as severe as in Alzheimer’s disease. Neuronal loss and gliosis are usually restricted to brainstem regions, particularly the substantia nigra and locus ceruleus.

Historical Terminology and Figures in Psychiatry

Paragraph 1: The term ‘learning disability’ was first used by Samuel Kirk in 1963 during a conference in Chicago. It is important for trainees to understand the history of terminology in psychiatry, including phrases like mental handicap, retardation, and intellectual disability, as they are associated with attitudes and concepts that have shaped care styles over the last century.

Paragraph 2: James Watts was a prominent practitioner and advocate of psychosurgery, a controversial treatment that involved surgical intervention in the brain to treat mental illness. His work has had a lasting impact on the field of psychiatry.

Paragraph 3: Wilhelm Griesinger, a German psychiatrist, is credited with describing ‘primary insanity’ (primäre verrücktheit), a term used to describe mental illness that arises without any apparent physical cause.

Paragraph 4: Johann Christian Reil, another German psychiatrist, is known for coining the term ‘psychiatry’ in the late 18th century. His work helped to establish psychiatry as a distinct field of medicine.

Paragraph 5: Charles Perry, an English physician, published ‘A mechanical account and explication of the hysterical passion’ in the 17th century. This work helped to shape early understandings of hysteria, a condition that was once believed to be caused by a ‘wandering womb’ in women.

The observation that haloperidol, which has a high D2 occupancy, has a greater likelihood of causing EPSE, while clozapine, which has a lower D2 occupancy, has a lower risk, is in line with the research.

Extrapyramidal side-effects (EPSE’s) are a group of side effects that affect voluntary motor control, commonly seen in patients taking antipsychotic drugs. EPSE’s include dystonias, parkinsonism, akathisia, and tardive dyskinesia. They can be frightening and uncomfortable, leading to problems with non-compliance and can even be life-threatening in the case of laryngeal dystonia. EPSE’s are thought to be due to antagonism of dopaminergic D2 receptors in the basal ganglia. Symptoms generally occur within the first few days of treatment, with dystonias appearing quickly, within a few hours of administration of the first dose. Newer antipsychotics tend to produce less EPSE’s, with clozapine carrying the lowest risk and haloperidol carrying the highest risk. Akathisia is the most resistant EPSE to treat. EPSE’s can also occur when antipsychotics are discontinued (withdrawal dystonia).

Neurotransmitters are substances used by neurons to communicate with each other and with target tissues. They are synthesized and released from nerve endings into the synaptic cleft, where they bind to receptor proteins in the cellular membrane of the target tissue. Neurotransmitters can be classified into different types, including small molecules (such as acetylcholine, dopamine, norepinephrine, serotonin, and GABA) and large molecules (such as neuropeptides). They can also be classified as excitatory or inhibitory. Receptors can be ionotropic or metabotropic, and the effects of neurotransmitters can be fast of slow. Some important neurotransmitters include acetylcholine, dopamine, GABA, norepinephrine, and serotonin. Each neurotransmitter has a specific synthesis, breakdown, and receptor type. Understanding neurotransmitters is important for understanding the function of the nervous system and for developing treatments for neurological and psychiatric disorders.

It is important to note that the question is asking for the option that is the most suggestive of a diagnosis of personality disorder with borderline pattern in the ICD-11. The correct answer is ‘transient, psychotic-like features’ as this is a qualifying element of the diagnosis. While the other options may also be present in individuals with this condition, they are not defining features.

Personality Disorder (Borderline)

History and Terminology

The term borderline personality disorder originated from early 20th-century theories that the disorder was on the border between neurosis and psychosis. The term borderline was coined by Adolph Stern in 1938. Subsequent attempts to define the condition include Otto Kernberg’s borderline personality organization, which identified key elements such as ego weakness, primitive defense mechanisms, identity diffusion, and unstable reality testing.

Features

The DSM-5 and ICD-11 both define borderline personality disorder as a pervasive pattern of instability in interpersonal relationships, self-image, and affects, and marked impulsivity. Symptoms include efforts to avoid abandonment, unstable relationships, impulsivity, suicidal behavior, affective instability, chronic feelings of emptiness, difficulty controlling temper, and transient dissociative symptoms.

Abuse

Childhood abuse and neglect are extremely common among borderline patients, with up to 87% having suffered some form of trauma. The effect of abuse seems to depend on the stage of psychological development at which it takes place.

comorbidity

Borderline PD patients are more likely to receive a diagnosis of major depressive disorder, bipolar disorder, panic disorder, PTSD, OCD, eating disorders, and somatoform disorders.

Psychological Therapy

Dialectical Behavioral Therapy (DBT), Mentalization-Based Treatment (MBT), Schema-Focused Therapy (SFT), and Transference-Focused Psychotherapy (TFP) are the main psychological treatments for BPD. DBT is the most well-known and widely available, while MBT focuses on improving mentalization, SFT generates structural changes to a patient’s personality, and TFP examines dysfunctional interpersonal dynamics that emerge in interactions with the therapist in the transference.

NICE Guidelines

The NICE guidelines on BPD offer very little recommendations. They do not recommend medication for treatment of the core symptoms. Regarding psychological therapies, they make reference to DBT and MBT being effective but add that the evidence base is too small to draw firm conclusions. They do specifically say Do not use brief psychotherapeutic interventions (of less than 3 months’ duration) specifically for borderline personality disorder of for the individual symptoms of the disorder.

Borderline personality disorder is often a result of childhood abuse of neglect, according to research. In the ICD-10, impulsive-unstable personality disorder is divided, and borderline PD is distinguished by a fundamental uncertainty about identity. Emotional instability is a common trait, and the patient’s self-image, goals, and internal preferences, including sexual preferences, are often unclear of disturbed. Chronic feelings of emptiness are also common. The patient may have a tendency to engage in unstable relationships, leading to emotional crises and efforts to avoid abandonment. Suicidal threats of self-harm may occur without obvious triggers.

Kluver-Bucy syndrome is a neurological disorder that results from dysfunction in both the right and left medial temporal lobes of the brain. This condition is characterized by a range of symptoms, including docility, altered dietary habits, hyperorality, and changes in sexual behavior. Additionally, individuals with Kluver-Bucy syndrome may experience visual agnosia, which is a condition that impairs their ability to recognize and interpret visual stimuli.

The individual’s age, behavioral changes, disinhibition, and fatuous giggling suggest a diagnosis of frontal lobe dementia, which is further supported by their physical examination. The absence of focal abnormalities on EEG rules out the possibility of vascular dementia. Typically, EEG results are normal during the early stages of this condition and remain so until the advanced stages.

Late-onset schizophrenia is characterized by paranoid delusions and auditory hallucinations as the main symptoms. Although a small proportion of patients may experience visual, tactile, of olfactory hallucinations, these are not the primary features of the disorder. It is important to rule out other medical conditions that may cause visual hallucinations, such as occipital lobe tumours, post-concussional state, epileptic twilight state, and metabolic disturbances. However, in cases where no underlying medical cause is found, Charles Bonnet syndrome should be considered as a possible explanation for complex visual hallucinations in individuals with impaired vision.

Rett Syndrome: A Rare Neurodevelopmental Disorder

Rett syndrome is a neurodevelopmental disorder that is rare, affecting approximately 1 in 10,000 female births. Although it mostly affects females, there have been cases of males with the disorder. While the exact cause of the disorder is not known, it is believed to have a genetic basis, with mutations in the MECP2 gene (Xq28) being associated with the disorder. Monozygotic twins have been found to have complete concordance in cases of Rett syndrome.

The disorder has a unique presentation, with affected children experiencing a normal period of development until 6-18 months. After this period, they begin to develop problems with language, losing previously acquired speech. Purposeful hand movements are replaced with stereotypic movements, such as hand wringing, and ataxia and psychomotor retardation may occur. Other stereotypical movements, such as finger licking of biting and tapping of slapping, may also be seen. Head circumference is normal at birth, but growth begins to decelerate between 6-12 months, resulting in microcephaly. All language skills are lost, both receptive and expressive, and social skills plateau at developmental levels between 6-12 months.

Seizures are associated with Rett syndrome in 75% of those affected, and almost all affected children have abnormal EEG findings. Breathing problems, such as hyperventilation, apnea, and breath holding, are also seen. Children with Rett syndrome may live for well over a decade after the onset of the disorder, but after 10 years, many patients are wheelchair-bound with virtually no language ability. Additional features of the disorder include seizures, breath holding and hyperventilation, sleep difficulties, and issues with locomotion.

Senile Pupil: A Common Age-Related Condition

The senile pupil, also known as senile miosis, is a condition commonly observed in older individuals. It is characterized by a small pupil that does not dilate in the dark, and may also be associated with reduced reaction to light and accommodation. This condition is often a result of age-related changes in the muscles that control the pupil, and can be exacerbated by certain medications of medical conditions. While it may not cause significant vision problems, it is important for individuals with senile pupil to have regular eye exams to monitor any changes in their vision and ensure proper eye health.

It is estimated that around 10% of individuals diagnosed with borderline personality disorder will ultimately take their own lives. While there may be some variation in the findings of different studies, this figure is widely accepted as the general rate of completed suicide among this population over an extended period of time.

The blood supply to the caudate nucleus primarily comes from the deep penetrators of the anterior and middle cerebral arteries. The effects of caudate infarcts can differ depending on the study, but typically include behavioral symptoms such as abulia and agitation, loss of executive function, and motor weakness.

Brain Blood Supply and Consequences of Occlusion

The brain receives blood supply from the internal carotid and vertebral arteries, which form the circle of Willis. The circle of Willis acts as a shunt system in case of vessel damage. The three main vessels arising from the circle are the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA). Occlusion of these vessels can result in various neurological deficits. ACA occlusion may cause hemiparesis of the contralateral foot and leg, sensory loss, and frontal signs. MCA occlusion is the most common and can lead to hemiparesis, dysphasia/aphasia, neglect, and visual field defects. PCA occlusion may cause alexia, loss of sensation, hemianopia, prosopagnosia, and cranial nerve defects. It is important to recognize these consequences to provide appropriate treatment.

Piaget’s cognitive theory involves the use of existing patterns of knowledge and behavior, known as schemas, through the process of assimilation. However, when faced with new situations, these schemas may need to be modified, which is known as accommodation. The theory is comprised of three main components: schemas, processes that facilitate the transition between stages (equilibrium, assimilation, and accommodation), and four stages of development: sensorimotor (0-2 years), preoperational (2-7 years), concrete operational (7-11 years), and formal operational (11+ years).

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.

– Visual aura is not expected in temporal lobe epilepsy
– Visual aura may occur in occipital seizures
– Temporal lobe epilepsy is characterized by automatisms, altered consciousness, déjà vu, complex partial seizures, and olfactory hallucinations
– Occipital epilepsy can cause visual phenomena and headaches
– Occipital epilepsy should be differentiated from migraine

This question is challenging as it requires an estimation of the percentage of Caucasians who possess two copies of the gene responsible for the slow-acting form of alcohol dehydrogenase.

Genetics and Alcoholism

Alcoholism tends to run in families, and several studies confirm that biological children of alcoholics are more likely to develop alcoholism even when adopted by parents without the condition. Monozygotic twins have a greater concordance rate for alcoholism than dizygotic twins. Heritability estimates range from 45 to 65 percent for both men and women. While genetic differences affect risk, there is no “gene for alcoholism,” and both environmental and social factors weigh heavily on the outcome.

The genes with the clearest contribution to the risk for alcoholism and alcohol consumption are alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2). The first step in ethanol metabolism is oxidation to acetaldehyde, by ADHs. The second step is metabolism of the acetaldehyde to acetate by ALDHs. Individuals carrying even a single copy of the ALDH2*504K display the “Asian flushing reaction” when they consume even small amounts of alcohol. There is one significant genetic polymorphism of the ALDH2 gene, resulting in allelic variants ALDH2*1 and ALDH2*2, which is virtually inactive. ALDH2*2 is present in about 50 percent of the Taiwanese, Han Chinese, and Japanese populations. It is extremely rare outside Asia. Nearly no individuals of European of African descent carry this allele. ALDH2*504K has repeatedly been demonstrated to have a protective effect against alcohol use disorders.

The three different class I gene loci, ADH1A (alpha), ADH1B (beta), and ADH1C (gamma) are situated close to each other in the region 4q2123. The alleles ADH1C*1 and ADH1B*2 code for fast metabolism of alcohol. The ADH1B*1 slow allele is very common among Caucasians, with approximately 95 percent having the homozygous ADH1B*1/1 genotype and 5 percent having the heterozygous ADH1B*1/2 genotype. The ADH1B*2 allele is the most common allele in Asian populations. In African populations, the ADH1B*1 allele is the most common.

The onset of DTs typically happens between three to five days after stopping drinking. However, tremulousness of withdrawal convulsions (also known as rum fits) can occur during a drinking binge of shortly after stopping drinking. Alcoholic hallucinosis, on the other hand, can develop over a period of days of weeks and is characterized by auditory hallucinations. Unlike DTs, it is typically accompanied by less severe agitation and mental confusion.