The Basal Ganglia: Functions and Disorders

The basal ganglia are a group of subcortical structures that play a crucial role in controlling movement and some cognitive processes. The components of the basal ganglia include the striatum (caudate, putamen, nucleus accumbens), subthalamic nucleus, globus pallidus, and substantia nigra (divided into pars compacta and pars reticulata). The putamen and globus pallidus are collectively referred to as the lenticular nucleus.

The basal ganglia are connected in a complex loop, with the cortex projecting to the striatum, the striatum to the internal segment of the globus pallidus, the internal segment of the globus pallidus to the thalamus, and the thalamus back to the cortex. This loop is responsible for regulating movement and cognitive processes.

However, problems with the basal ganglia can lead to several conditions. Huntington’s chorea is caused by degeneration of the caudate nucleus, while Wilson’s disease is characterized by copper deposition in the basal ganglia. Parkinson’s disease is associated with degeneration of the substantia nigra, and hemiballism results from damage to the subthalamic nucleus.

In summary, the basal ganglia are a crucial part of the brain that regulate movement and some cognitive processes. Disorders of the basal ganglia can lead to significant neurological conditions that affect movement and other functions.

Waxy flexibility involves the examiner imposing postures on the patient, while posturing involves spontaneous postures. On the other hand, mitgehen is a type of automatic obedience where the examiner can easily move the patient’s body with a gentle touch, but unlike waxy flexibility, the body part quickly returns to its original position.

– Catatonia is a psychiatric syndrome characterized by disturbed motor functions, mood, and thought.
– Key behaviors associated with catatonia include stupor, posturing, waxy flexibility, negativism, automatic obedience, mitmachen, mitgehen, ambitendency, psychological pillow, forced grasping, obstruction, echopraxia, aversion, mannerisms, stereotypies, motor perseveration, echolalia, and logorrhoea.
– These behaviors are often tested in exam questions.
– Karl Ludwig Kahlbaum is credited with the original clinical description of catatonia.

Narrow Therapeutic Index Drugs

Narrow therapeutic index (NTI) drugs are medications that have a small difference between the amount that causes a therapeutic effect and the amount that causes toxicity. In other words, the therapeutic index (TI) of these drugs is narrow. The TI is a ratio that compares the blood concentration at which a drug causes a therapeutic effect to the amount that causes death of toxicity.

In clinical practice, the TI is the range of doses at which a medication appeared to be effective in clinical trials for a median of participants without unacceptable adverse effects. For most drugs, this range is wide enough, and the maximum plasma concentration of the drug achieved when the recommended doses of a drug are prescribed lie sufficiently above the minimum therapeutic concentration and sufficiently below the toxic concentration.

However, some drugs have a narrow therapeutic index, which means that even small changes in dose of blood concentration can lead to serious adverse effects. The US Food and Drug Administration (FDA) defines a drug product as having an NTI when there is less than a twofold difference in the minimum toxic concentrations and minimum effective concentrations in the blood and safe and effective use of the drug requires careful titration and patient monitoring.

Examples of drugs with a narrow therapeutic index include carbamazepine, lithium, phenytoin, warfarin, digoxin, and gentamicin. These drugs require close monitoring to ensure that the blood concentration remains within the therapeutic range and does not reach toxic levels.

Antipsychotic drugs are known to cause weight gain, but some more than others. The reason for this is not due to a direct metabolic effect, but rather an increase in appetite and a decrease in activity levels. The risk of weight gain appears to be linked to clinical response. There are several suggested mechanisms for this, including antagonism of certain receptors and hormones that stimulate appetite. The risk of weight gain varies among different antipsychotics, with clozapine and olanzapine having the highest risk. Management strategies for antipsychotic-induced weight gain include calorie restriction, low glycemic index diet, exercise, and switching to an alternative antipsychotic. Aripiprazole, ziprasidone, and lurasidone are recommended as alternative options. Other options include aripiprazole augmentation, metformin, orlistat, liraglutide, and topiramate.

Understanding Grief: Normal and Abnormal Phases

Grief is a natural response to loss, and it is a complex process that can take different forms and durations. John Bowlby and Kubler-Ross have proposed models to describe the typical phases of grief, which can vary in intensity and duration for each individual. Bowlby’s model includes shock-numbness, yearning-searching, disorganization-despair, and reorganization, while Kubler-Ross’s model includes denial-dissociation-isolation, anger, bargaining, depression, and acceptance.

However, some people may experience abnormal grief, which can be categorized as inhibited, delayed, of chronic/prolonged. Inhibited grief refers to the absence of expected grief symptoms at any stage, while delayed grief involves avoiding painful symptoms within two weeks of loss. Chronic/prolonged grief is characterized by continued significant grief-related symptoms six months after loss.

It is important to distinguish between normal grief and major depression, as a high proportion of people may meet the criteria for major depression in the first year following bereavement. Some features that can help differentiate between the two include generalized guilt, thoughts of death unrelated to the deceased, feelings of worthlessness, psychomotor retardation, and prolonged functional impairment.

Overall, understanding the phases and types of grief can help individuals and their loved ones navigate the grieving process and seek appropriate support and resources.

Antidepressants: Minimum Effective Doses

According to the Maudsley 13th, the following are the minimum effective doses for various antidepressants:

– Citalopram: 20 mg/day
– Fluoxetine: 20 mg/day
– Fluvoxamine: 50 mg/day
– Paroxetine: 20 mg/day
– Sertraline: 50 mg/day
– Mirtazapine: 30 mg/day
– Venlafaxine: 75 mg/day
– Duloxetine: 60 mg/day
– Agomelatine: 25 mg/day
– Moclobemide: 300 mg/day
– Trazodone: 150 mg/day

Note that these are minimum effective doses and may vary depending on individual factors and response to treatment. It is important to consult with a healthcare professional before starting of changing any medication regimen.

Argyll Robertson Pupil: Accommodation Retained

The Argyll Robertson pupil is a notable topic in medical exams, as it is associated with tertiary syphilis, which is a crucial differential diagnosis for various psychiatric conditions like mood disorders, dementia, and psychosis. This type of pupil reacts poorly to light but normally to near stimuli, such as accommodation and convergence. They are typically small and irregular in shape, but they do not usually affect visual acuity. Mydriatic agents are not effective in dilating the Argyll Robertson pupil. Although this type of pupil is often considered pathognomonic of tertiary syphilis, it has also been observed in diabetes.

The term paramnesia refers to memory disorders where fantasy and reality are confused. There are various types of paramnesias, including déjà vu, jamais vu, confabulation, reduplicative paramnesia, retrospective falsification, and cryptomnesia. Reduplicative paramnesia is a subset of delusional misidentification syndromes, which include Capgras delusion, the Fregoli delusion, and others. A review of reduplicative paramnesia was conducted by Politis in 2012.

Conjugation is involved in Phase II reactions, but it is not necessary for these reactions to occur in a specific order. They can occur in reverse order, with Phase II preceding Phase I, of as a single reaction.

Understanding Biotransformation: A Metabolic Process for Excretion

Biotransformation is a metabolic process that occurs primarily in the liver, but also in other organs such as the kidneys, intestine, adipose, skin, and lungs. Its main function is to facilitate the excretion of both exogenous and endogenous substances by altering their chemical structures through a series of reactions. Enzymes found in the cytoplasm, endoplasmic reticulum, and mitochondria of cells catalyze these reactions, which can cause the substrate to become inactive, active, of even toxic.

Biotransformation is divided into three phases. Phase I reactions involve oxidation, reduction, of hydrolysis of the drug, yielding a polar, water-soluble metabolite that is often still active. Phase II reactions consist of adding hydrophilic groups to the original molecule, a toxic intermediate, of a nontoxic metabolite formed in phase I, to increase its polarity. The most common method is conjugation with glucuronic acid, but other groups such as sulphate, amino acids, acetate, and methyl can also be added. Phase III reactions occur post-phase II, where a chemical substance can undergo further metabolism and excretion through active transport into the urinary of hepatobiliary system.

Understanding biotransformation is crucial in pharmacology and toxicology, as it affects the efficacy and toxicity of drugs and other substances. By facilitating the excretion of these substances, biotransformation helps maintain homeostasis in the body and prevent accumulation of potentially harmful compounds.

Pharmacological management of dementia involves the use of acetylcholinesterase inhibitors (AChE inhibitors) and memantine. AChE inhibitors prevent the breakdown of acetylcholine, which is deficient in Alzheimer’s due to the loss of cholinergic neurons. Donepezil, galantamine, and rivastigmine are commonly used AChE inhibitors in the management of Alzheimer’s. However, gastrointestinal side effects such as nausea and vomiting are common with these drugs.

Memantine, on the other hand, is an NMDA receptor antagonist that blocks the effects of pathologically elevated levels of glutamate that may lead to neuronal dysfunction. It has a half-life of 60-100 hours and is primarily renally eliminated. Common adverse effects of memantine include somnolence, dizziness, hypertension, dyspnea, constipation, headache, and elevated liver function tests.

Overall, pharmacological management of dementia aims to improve cognitive function and slow down the progression of the disease. However, it is important to note that these drugs do not cure dementia and may only provide temporary relief of symptoms.

The term PrPSc originated from scrapie, a prion disease that affects sheep. In humans, the normal isoform of prion protein is PrPC, while the abnormal form is known as PrPres (protease-resistant) of PrPSc. Scrapie has been observed in sheep for over 300 years, while BSE in cattle was only identified in the 1980s. Feline spongiform encephalopathy (FSE) is a prion disease that affects cats, and Chronic wasting disease (CWD) is a similar condition that affects deer.

With aging, there is an increase in lean body weight and body water and a decrease in the proportion of fat. As a result, water-soluble drugs are distributed to a greater extent. Lipid-soluble drugs have a lower volume of distribution in the elderly due to the lower proportion of body fat.

Prescribing medication for elderly individuals requires consideration of their unique pharmacokinetics and pharmacodynamics. As the body ages, changes in distribution, metabolism, and excretion can affect how medication is absorbed and processed. For example, reduced gastric acid secretion and motility can impact drug absorption, while a relative reduction of body water to body fat can alter the distribution of lipid soluble drugs. Additionally, hepatic metabolism of drugs decreases with age, and the kidneys become less effective, leading to potential accumulation of certain drugs.

In terms of pharmacodynamics, receptor sensitivity tends to increase during old age, meaning smaller doses may be needed. However, older individuals may also take longer to respond to treatment and have an increased incidence of side-effects. It is important to start with a lower dose and monitor closely when prescribing medication for elderly patients, especially considering the potential for interactions with other medications they may be taking.

Corrigan and Watson identified two types of stigma: public stigma and self-stigma. The individual in this example has developed low self-esteem due to agreeing with prejudicial beliefs about mental illness. Public stigma involves negative beliefs about a group, such as dangerousness of incompetence, while public prejudice involves a negative emotional reaction, such as fear. Self-stigma refers to negative self-beliefs, such as character weakness of incompetence, and self-discrimination is a behavioral response to prejudice, such as avoiding work. Hayward and Bright2 identified four recurring themes behind stigma against mental illness: dangerousness, attribution of responsibility, poor prognosis, and disruption of social interaction.

The idea of filial imprinting was initially observed in domestic chickens by Douglas Spalding in the 1800s, and later discussed by Heinroth before being made well-known by Lorenz. Additionally, Immelmann discussed sexual imprinting, while Westermarck introduced the concept of reverse sexual imprinting, which suggests that individuals who spend their early years in close proximity are less likely to be sexually attracted to each other later in life.

Hallucinations that occur when falling asleep are called hypnagogic and are typically short and basic, such as simple sounds of flashes of light. Non-complex hallucinations, like sudden noises of brief flashes, are referred to as elementary hallucinations and can happen at any time. Tactile hallucinations are also known as haptic hallucinations. On the other hand, hypnopompic hallucinations are experienced upon waking up. It’s important to note that pseudohallucinations are not related to sleep and do not have the same quality as real perceptions.

Dementia Praecox: An Old Term for Schizophrenia

Dementia praecox, also known as premature dementia, was a term created by Emil Kraepelin to describe a mental disorder that we now know as schizophrenia. This term is no longer used in modern psychiatric diagnosis, but it was once a widely recognized term for the condition. Kraepelin used the term to describe a group of symptoms that included delusions, hallucinations, disordered thinking, and emotional flatness.

Today, we understand schizophrenia to be a complex and chronic mental illness that affects approximately 1% of the population worldwide. While the term dementia praecox is no longer used, it is important to recognize its historical significance in the development of our understanding of schizophrenia. By studying the evolution of psychiatric terminology, we can gain insight into the changing perceptions of mental illness over time.

The WCST is a test that assesses frontal lobe function by presenting the patient with cards that vary in shape, color, and number. The patient is asked to sort the cards based on one of these dimensions and then switch to another dimension. Patients with frontal lobe damage may struggle with inflexible thinking and inhibiting previously correct answers.

The Benton visual retention test is a test of visual memory that does not assess frontal lobe function. The patient is shown geometric shapes for ten seconds and then asked to draw them from memory.

The NART is a test that measures premorbid IQ.

The Rorschach inkblot test is a projective personality test.

The Rey-Osterrieth complex figure test assesses visuospatial skills. The patient is asked to copy a complex figure and then reproduce it from memory.

Phenomena of Memory

There are several phenomena related to memory that people may experience. Jamais vu is when someone cognitively knows they have experienced a situation, but it does not feel familiar to them. Confabulation is when someone falsifies a memory while in clear consciousness. Déjà vu is a feeling of familiarity for a new event that has not been experienced before. Derealisation is a feeling of unreality in perception and altered feelings towards perceived objects. Finally, panoramic recall is when a patient feels like they are rapidly re-enacting long periods of their life.

The Flynn Effect is the term used to describe the increase in standardised intelligence test scores over time. Research conducted by Flynn showed that IQ scores increased by 13.8 points between 1932 and 1978, which equates to a 0.3-point increase per year of approximately 3 points per decade. More recent studies have also supported the Flynn effect, with IQ score gains observed between 1972 and 2006. This means that an individual is likely to achieve a higher IQ score on an earlier version of a test than on the current version. In fact, the test will overestimate an individual’s IQ score by an average of 0.3 points per year between the year in which the test was normed and the year in which the test was administered.

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.

Citalopram can moderately prolong QTc (>10 msec), while aripiprazole and paliperidone have no effect. Haloperidol and pimozide have a high effect, and quetiapine and amisulpride have a moderate effect. Clozapine, risperidone, and olanzapine have a low effect (<10 msec prolongation). Lamotrigine, mirtazapine, and SSRIs (excluding citalopram) do not have an effect on QTc interval.

Behaviour change theories can be categorized into two main groups: social cognition models and stage models. Stage models involve progression through specific stages, while social cognition models focus on beliefs and attitudes as drivers of behaviour change. Examples of social cognition models include the health belief model, protection motivation theory, and self-efficacy theory.

If a patient presents with confusion, eye signs (ophthalmoplegia of nystagmus), and an ataxic gait, Wernicke’s encephalopathy should be suspected. This serious, but reversible, condition is most commonly caused by alcohol dependence and is due to a lack of Vitamin B1 (thiamine). Acute alcohol intoxication is unlikely as the patient’s blood alcohol level is below the legal limit for driving. Amnesic syndrome is not the correct diagnosis as it is characterized by impairment of new learning without obvious confusion. Normal pressure hydrocephalus is characterized by urinary incontinence, gait disturbance, and cognitive decline. Subdural hematoma is not a likely diagnosis as there is no history of head injury.

Patients with existing ischaemic heart disease who experience depression have a relative risk of cardiac morbidity and mortality that ranges from 1.5 to 2.5.

The Hawthorne effect is a type of bias that occurs when individuals alter their behavior because they believe they are being observed. The halo effect is a cognitive bias where one’s perception of a trait is influenced by their perception of another trait, such as assuming someone with glasses is intelligent. The Forer effect explains why people give high accuracy ratings to personality descriptions that are actually vague and general enough to apply to many people, as seen in practices like astrology. The interloper effect is the tendency to view third-party consultation as objective. The practice effect refers to the impact of past experience on taking a test again, resulting in higher scores, especially when the interval between tests is short.

The Hawthorne Effect and Its Impact on Research

The Hawthorne effect is a type of observer bias that occurs when individuals modify their behavior because they believe they are being observed. This phenomenon can have a significant impact on research outcomes, as subjects may alter their actions of responses in an attempt to please the observer of researcher. For instance, if a person knows they are being watched while performing a task, they may complete it more quickly of with greater accuracy than they would otherwise. As a result, researchers must be aware of the Hawthorne effect and take steps to minimize its influence on their studies. Failure to do so can lead to inaccurate of misleading results, which can have serious consequences for the validity of the research.

The percentage of women who experience specific phobia at some point in their lives is 13%. The percentage of people who experience obsessive compulsive disorder within a year is 2.1%. The percentage of women who experience agoraphobia without panic disorder within a year is 3.8%. The percentage of men who experience specific phobia at some point in their lives is 4%. The percentage of people in the US National Comorbidity study who experience social phobia within a year is 7.4%. All of these statistics are based on the diagnostic criteria outlined in DSM-III R.

Assessment Tools for Schizophrenia

There are several assessment tools available for use in patients with schizophrenia. The Brief Psychiatric Rating Scale (BPRS) is a semi-structured interview that covers 18 items, including positive symptoms, general psychopathology, and affective symptoms. Another tool that can be used to assess psychotic symptoms in schizophrenia is the Positive and Negative Symptom Scale (PANSS).

The Beck Depression Inventory is a self-report questionnaire that consists of 21 items. However, it does not include any questions about psychotic symptoms. The General Health Questionnaire is a screening tool for mental illness, but the 12-item version does not contain any questions about psychosis.

The Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS) is a tool that asks about the side effects of neuroleptics, including extrapyramidal, hyperprolactinemia, and autonomic effects. Finally, the Wechsler Adult Intelligence Scale (WAIS) is an intelligence test that is specifically designed for use in adults.

Occupational Classification:

The Office of Population Censuses and Surveys has developed a social and occupational classification system that categorizes individuals based on their employment status and level of skill. The system includes six social classes, ranging from unemployed of student (social class 0) to professional (social class I).

Social class I includes individuals who hold professional positions, such as doctors, lawyers, and engineers. These individuals typically have advanced degrees and specialized training in their field.

Social class II includes intermediate positions, such as managers, supervisors, and technicians. These individuals may have some level of specialized training of education, but not to the same extent as those in social class I.

Social class III includes skilled, manual, of clerical positions, such as electricians, mechanics, and administrative assistants. These individuals have a high level of skill in their field and may require some level of training of certification.

Social class IV includes semi-skilled positions, such as factory workers, machine operators, and retail salespeople. These individuals may have some level of training of experience, but not to the same extent as those in social class III.

Social class V includes unskilled positions, such as laborers, cleaners, and agricultural workers. These individuals typically do not require any specialized training of education and may perform manual labor of basic tasks.

Patients may feel that they have lost control over their thoughts, which can manifest as passivity of thought. This refers to the belief that an external agency is controlling one’s thoughts. Passivity can take different forms, such as thought withdrawal, thought insertion, and thought broadcasting.

Ego (Boundary) Disturbances

Ego (boundary) disturbances refer to experiences where there is a disturbance in the perception of self as distinct from the environment of the integrity of self. It also includes instances where bodily processes, personal thought processes, feelings, and actions are experienced as being externally directed. These phenomena are referred to as passivity phenomena, and some of the symptom characteristics are classified as bizarre delusional phenomena in the DSM.

Derealization is when a patient experiences their surroundings of time as if they are unreal and changed, losing all feelings of familiarity and trust in the environment. People, objects, and surroundings appear unreal, unfamiliar, of spatially altered. The sensations may be intense of weak in nature.

Depersonalization is when a patient perceives themselves as alien, unreal, changed, of as a stranger. The disturbances of depersonalization may be of a transient nature only of become more persistent over a longer period of time. It is generally felt to be both strange and unpleasant.

Thought broadcasting is when a patient’s personal thoughts are experienced as no longer belonging to the patient alone but accessible by others who will know what the patient is thinking (mind reading). Thought withdrawal is when a patient’s thoughts are being removed of stripped from them. Thought insertion is when patients experience their thoughts and ideas as being externally influenced, made externally, controlled, directed, entered/ of externally imposed.

Other feelings of alien influence refer to feelings, intentions, behavior, of bodily functions that are experienced as externally controlled of made by others (passivity phenomena). The patient feels externally compelled to say something specific, to scream, to act of behave in a particular way, to attack someone, to throw a tantrum, etc.

If a patient is unable to complete a task that requires a sequence of steps, they are exhibiting ideational apraxia. On the other hand, if they struggle to perform a task that they have previously learned, such as attempting to brush their teeth with a pencil, this is an example of ideomotor apraxia.

Apraxia: Understanding the Inability to Carry Out Learned Voluntary Movements

Apraxia is a neurological condition that affects a person’s ability to carry out learned voluntary movements. It is important to note that this condition assumes that everything works and the person is not paralyzed. There are different types of apraxia, each with its own set of symptoms and characteristics.

Limb kinetic apraxia is a type of apraxia that affects a person’s ability to make fine of delicate movements. This can include tasks such as buttoning a shirt of tying shoelaces.

Ideomotor apraxia, on the other hand, is an inability to carry out learned tasks when given the necessary objects. For example, a person with ideomotor apraxia may try to write with a hairbrush instead of using it to brush their hair.

Constructional apraxia affects a person’s ability to copy a picture of combine parts of something to form a whole. This can include tasks such as building a puzzle of drawing a picture.

Ideational apraxia is an inability to follow a sequence of actions in the correct order. For example, a person with ideational apraxia may struggle to take a match out of a box and strike it with their left hand.

Finally, oculomotor apraxia affects a person’s ability to control eye movements. This can make it difficult for them to track moving objects of read smoothly.

Overall, apraxia can have a significant impact on a person’s ability to carry out everyday tasks. However, with the right support and treatment, many people with apraxia are able to improve their abilities and maintain their independence.