Lesions of the vagus nerve commonly result in the following symptoms: a raspy of weak voice, difficulty swallowing, absence of the gag reflex, deviation of the uvula away from the affected side, and an inability to elevate the palate.

Overview of Cranial Nerves and Their Functions

The cranial nerves are a complex system of nerves that originate from the brain and control various functions of the head and neck. There are twelve cranial nerves, each with a specific function and origin. The following table provides a simplified overview of the cranial nerves, including their origin, skull exit, modality, and functions.

The first cranial nerve, the olfactory nerve, originates from the telencephalon and exits through the cribriform plate. It is a sensory nerve that controls the sense of smell. The second cranial nerve, the optic nerve, originates from the diencephalon and exits through the optic foramen. It is a sensory nerve that controls vision.

The third cranial nerve, the oculomotor nerve, originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement, pupillary constriction, and lens accommodation. The fourth cranial nerve, the trochlear nerve, also originates from the midbrain and exits through the superior orbital fissure. It is a motor nerve that controls eye movement.

The fifth cranial nerve, the trigeminal nerve, originates from the pons and exits through different foramina depending on the division. It is a mixed nerve that controls chewing and sensation of the anterior 2/3 of the scalp. It also tenses the tympanic membrane to dampen loud noises.

The sixth cranial nerve, the abducens nerve, originates from the pons and exits through the superior orbital fissure. It is a motor nerve that controls eye movement. The seventh cranial nerve, the facial nerve, also originates from the pons and exits through the internal auditory canal. It is a mixed nerve that controls facial expression, taste of the anterior 2/3 of the tongue, and tension on the stapes to dampen loud noises.

The eighth cranial nerve, the vestibulocochlear nerve, originates from the pons and exits through the internal auditory canal. It is a sensory nerve that controls hearing. The ninth cranial nerve, the glossopharyngeal nerve, originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls taste of the posterior 1/3 of the tongue, elevation of the larynx and pharynx, and swallowing.

The tenth cranial nerve, the vagus nerve, also originates from the medulla and exits through the jugular foramen. It is a mixed nerve that controls swallowing, voice production, and parasympathetic supply to nearly all thoracic and abdominal viscera. The eleventh cranial nerve, the accessory nerve, originates from the medulla and exits through the jugular foramen. It is a motor nerve that controls shoulder shrugging and head turning.

The twelfth cranial nerve, the hypoglossal nerve, originates from the medulla and exits through the hypoglossal canal. It is a motor nerve that controls tongue movement. Overall, the cranial nerves play a crucial role in controlling various functions of the head and neck, and any damage of dysfunction can have significant consequences.

Historical Classification of Schizophrenia

The classification of schizophrenia has evolved over time, with various individuals contributing to its development. In 1801, Phillippe Pinel used the term ‘demencé’ to describe the loss of mental abilities in chronically ill patients. Benedict Morel coined the term ‘demencé precocé’ in 1852 to describe young patients with premature dementia. Kahlbaum was the first to describe ‘paraphrenia hebetica’ in the 1860s, which was later elaborated as ‘hebephrenia’ by Hecker in 1871.

In 1893, Emil Kraepelin used the term dementia praecox to describe the condition, emphasizing the importance of delusions, hallucinations, impaired attention, thought incoherence, stereotyped movements and expressions, deterioration of emotional life, and a loss of drive as key symptoms. In 1908, Eugen Bleuler coined the term ‘schizophrenia’ to replace dementia praecox, denoting ‘a splitting of the psychic functions.’ Bleuler expanded the concept to include presentations that did not include a ‘terminal state.’

Bleuler introduced a distinction between basic and accessory symptoms and primary and secondary symptoms. Basic symptoms are necessarily present in any case of schizophrenia, while accessory symptoms may of may not occur. The fundamental features of schizophrenia were loosening of associations, disturbances of affectivity, ambivalence, and autism. The alteration of associations is the only symptom that Bleuler regarded as both basic and primary, and can thus be described as the core disturbance in the Bleulerian conception of schizophrenia.

In 1939, Langfeldt introduced the term ‘schizophreniform psychosis’ to describe patients with Bleulerian schizophrenia who did not follow a progressively deteriorating course. In the 1960s, Rado/Meehl introduced the term ‘schizotypy’ to recognize the concept of a continuum of spectrum of schizophrenia-related phenotypes. In the 1980s, Crow proposed a subclassification of schizophrenia, dividing patients into types I and II. Type I patients present with positive symptoms such as delusions and hallucinations, while type II patients present with negative symptoms such as affective flattening and poverty of speech.

Attitude scales are used to measure a person’s feelings and thoughts towards something. There are several types of attitude scales, including the Thurstone scale, Likert scale, semantic differential scale, and Gutman scale. The Thurstone scale involves creating a list of statements and having judges score them based on their negativity of positivity towards an issue. Respondents then indicate whether they agree of disagree with each statement. The Likert scale asks respondents to indicate their degree of agreement of disagreement with a series of statements using a five-point scale. The semantic differential scale presents pairs of opposite adjectives and asks respondents to rate their position on a five- of seven-point scale. The Gutman scale involves a list of statements that can be ordered hierarchically, with each statement having a corresponding weight. Respondents’ scores on the scale indicate the number of statements they agree with.

Genomics: Understanding DNA, RNA, Transcription, and Translation

Deoxyribonucleic acid (DNA) is a molecule composed of two chains that coil around each other to form a double helix. DNA is organised into chromosomes, and each chromosome is made up of DNA coiled around proteins called histones. RNA, on the other hand, is made from a long chain of nucleotide units and is usually single-stranded. RNA is transcribed from DNA by enzymes called RNA polymerases and is central to protein synthesis.

Transcription is the synthesis of RNA from a DNA template, and it consists of three main steps: initiation, elongation, and termination. RNA polymerase binds at a sequence of DNA called the promoter, and the transcriptome is the collection of RNA molecules that results from transcription. Translation, on the other hand, refers to the synthesis of polypeptides (proteins) from mRNA. Translation takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein.

The process of translation involves messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Transfer RNAs, of tRNAs, connect mRNA codons to the amino acids they encode, while ribosomes are the structures where polypeptides (proteins) are built. Like transcription, translation also consists of three stages: initiation, elongation, and termination. In initiation, the ribosome assembles around the mRNA to be read and the first tRNA carrying the amino acid methionine. In elongation, the amino acid chain gets longer, and in termination, the finished polypeptide chain is released.

Alcohol screening tools are available to assist in the diagnosis of alcohol problems. One such tool is the AUDIT (Alcohol Use Disorders Identification Test), which consists of 10 questions and covers harmful use, hazardous use, and dependence. Another tool is the FAST (Fast Alcohol Screening Test), which has just 4 questions and was developed for use in a busy medical setting. The CAGE is a well-known 4 question screening tool, but recent research has questioned its value. Other tools include SASQ (Single alcohol screening questionnaire), PAT (Paddington Alcohol Test), MAST (Michigan Alcoholism Screening Test), and RAPS4 (Rapid Alcohol Problem Screen 4). These tools can help identify hazardous of harmful alcohol consumption and alcohol dependence.

The Thurstone scale’s reliability is limited due to the process of constructing it. While a large number of statements are collected and edited for clarity and relevance, the final form of the scale only includes items that have high interjudge agreement and fall at equal intervals. This selective process may result in a scale that is not entirely reliable.

Theories of aggression can be categorized into three main perspectives: psychodynamic, sociological/drive, and cognitive and learning. Psychodynamic theory, proposed by Freud, suggests that aggression arises from a primary instinct called thanatos, which aims for destruction and death. Sociobiological/drive theory, proposed by Lorenz, suggests that aggression is instinctual and necessary for survival, and that stronger genes are selected through aggression. Cognitive and learning theory, proposed by Berkowitz, Rotter, Bandura, and Anderson, suggests that aggression can be learned through observational learning and is influenced by environmental factors. Bandura’s work introduced the concept of reciprocal determinism, which suggests that behavior is influenced by both the environment and the individual’s behavior. Rotter’s social learning theory emphasizes the interaction between the individual and their environment, while Anderson and Bushman’s general aggression model considers the role of social, cognitive, developmental, and biological factors on aggression.

In zero order kinetics, the elimination of a drug occurs at a constant rate regardless of its concentration in the plasma. This results in a linear relationship between the plasma concentration and time from peak concentration. Unlike drugs that follow first order kinetics, drugs that follow zero order kinetics do not have a fixed half-life.

The half-life of a drug is the time taken for its concentration to fall to one half of its value. Drugs with long half-lives may require a loading dose to achieve therapeutic plasma concentrations rapidly. It takes about 4.5 half-lives to reach steady state plasma levels. Most drugs follow first order kinetics, where a constant fraction of the drug in the body is eliminated per unit time. However, some drugs may follow zero order kinetics, where the plasma concentration of the drug decreases at a constant rate, despite the concentration of the drug. For drugs with nonlinear kinetics of dose-dependent kinetics, the relationship between the AUC of CSS and dose is not linear, and the kinetic parameters may vary depending on the administered dose.

While adherence, compliance, and capacitance all refer to how well a patient follows a doctor’s instructions, they do not have the same meaning as concordance, which specifically refers to the agreement between patient and doctor on a treatment plan.

As people age, they tend to have less muscle mass, more fat, and less water in their bodies. As a result, drugs that dissolve in fat tend to spread out more in their bodies. This can cause the effects of these drugs to last longer even after they stop taking them.

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.

Freud’s Structural Theory: Understanding the Three Areas of the Mind

According to Freud’s structural model, the human mind is divided into three distinct areas: the Id, the Ego, and the Superego. The Id is the part of the mind that contains instinctive drives and operates on the ‘pleasure principle’. It functions without a sense of time and is governed by ‘primary process thinking’. The Ego, on the other hand, attempts to modify the drives from the Id with external reality. It operates on the ‘reality principle’ and has conscious, preconscious, and unconscious aspects. It is also home to the defense mechanisms. Finally, the Superego acts as a critical agency, constantly observing a person’s behavior. Freud believed that it developed from the internalized values of a child’s main caregivers. The Superego contains the ‘ego ideal’, which represents ideal attitudes and behavior. It is often referred to as the conscience. Understanding these three areas of the mind is crucial to understanding Freud’s structural theory.

The three major types of learning are: operant conditioning, classical conditioning, and observational learning. In operant conditioning, an individual’s behavior is instrumental in achieving a desired outcome. In classical conditioning, a neutral stimulus is paired with a stimulus that already evokes a reflex response, eventually leading to the new stimulus evoking a similar response. Observational learning involves learning through the observation of others. Shaping, a part of operant conditioning, involves reinforcing successive approximations to a desired behavior. Extinction, seen in both classical and operant conditioning, involves the observed behavior gradually stopping due to the absence of reinforcement of presentation of the stimulus alone.

The DSM-5 employs the label ‘borderline personality disorder’, while the previous ICD utilized the term ’emotionally unstable personality disorder’, which was not included in the ICD-11. The ICD-11 now allows for the use of a borderline qualifier when providing a broad diagnosis of personality disorder.

Personality Disorder Classification

A personality disorder is a persistent pattern of behavior and inner experience that deviates significantly from cultural expectations, is inflexible and pervasive, and causes distress of impairment. The DSM-5 and ICD-11 have different approaches to classifying personality disorders. DSM-5 divides them into 10 categories, grouped into clusters A, B, and C, while ICD-11 has a general category with six trait domains that can be added. To diagnose a personality disorder, the general diagnostic threshold must be met before determining the subtype(s) present. The criteria for diagnosis include inflexibility and pervasiveness of the pattern, onset in adolescence of early adulthood, stability over time, and significant distress of impairment. The disturbance must not be better explained by another mental disorder, substance misuse, of medical condition.

Course

Borderline and antisocial personality disorders tend to become less evident of remit with age, while others, particularly obsessive-compulsive and schizotypal, may persist.

Classification

The DSM-5 divides personality disorders into separate clusters A, B, and C, with additional groups for medical conditions and unspecified disorders. The ICD-11 dropped the separate categories and instead lists six trait domains that can be added to the general diagnosis.

UK Epidemiology

The prevalence of personality disorders in Great Britain, according to the British National Survey of Psychiatric Morbidity, is 4.4%, with cluster C being the most common at 2.6%, followed by cluster A at 1.6% and cluster B at 1.2%. The most prevalent specific personality disorder is obsessive-compulsive (anankastic) at 1.9%.

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.

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.

Agnosia is a condition where a person loses the ability to recognize objects, persons, sounds, shapes, of smells, despite having no significant memory loss of defective senses. There are different types of agnosia, such as prosopagnosia (inability to recognize familiar faces), anosognosia (inability to recognize one’s own condition/illness), autotopagnosia (inability to orient parts of the body), phonagnosia (inability to recognize familiar voices), simultanagnosia (inability to appreciate two objects in the visual field at the same time), and astereoagnosia (inability to recognize objects by touch).

While XYY has been proposed as a potential contributor to aggressive behavior, it is more likely that the observed increase in aggression among individuals with this genetic makeup is a result of other factors such as low IQ and social deprivation, which are more prevalent in the XYY population. Therefore, XYY is not considered to be the sole cause of aggressiveness.

XYY Syndrome

XYY Syndrome, also known as Jacobs’ Syndrome of super-males, is a genetic condition where males have an extra Y chromosome, resulting in a 47, XYY karyotype. In some cases, mosaicism may occur, resulting in a 47,XYY/46,XY karyotype. The error leading to the 47,XYY genotype occurs during spermatogenesis of post-zygotic mitosis. The prevalence of XYY Syndrome is as high as 1:1000 male live births, but many cases go unidentified as they are not necessarily associated with physical of cognitive impairments. The most common features are high stature and a strong build, and fertility and sexual development are usually unaffected. In the past, XYY Syndrome was linked to aggressiveness and deviance, but this is likely due to intermediate factors such as reduced IQ and social deprivation. XYY Syndrome is best thought of as a risk factor rather than a cause. There is an increased risk of developmental disorders such as learning difficulties, ASD, ADHD, and emotional problems.

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.

Stevens-Johnson syndrome is a severe skin condition that can be caused by medication use of infection. Anticonvulsants, particularly lamotrigine, are often the cause. Symptoms include fever, sore throat, fatigue, and the appearance of ulcers and lesions in the mucous membranes. A rash of round lesions also appears on the face, trunk, arms, legs, and soles of the feet. It is a life-threatening condition that requires immediate medical attention.

The man’s longing for his girlfriend and the traveller’s thirst create affect illusions, distorting their perceptions. The woman who hears her mother when she sees the door open experiences a reflex hallucination, while the man who hears his wife’s voice describing something outside of his surroundings experiences an extracampine hallucination.

Altered Perceptual Experiences

Disorders of perception can be categorized into sensory distortions and sensory deceptions. Sensory distortions involve changes in the intensity, spatial form, of quality of a perception. Examples include hyperaesthesia, hyperacusis, and micropsia. Sensory deceptions, on the other hand, involve new perceptions that are not based on any external stimulus. These include illusions and hallucinations.

Illusions are altered perceptions of a stimulus, while hallucinations are perceptions in the absence of a stimulus. Completion illusions, affect illusions, and pareidolic illusions are examples of illusions. Auditory, visual, gustatory, olfactory, and tactile hallucinations are different types of hallucinations. Pseudohallucinations are involuntary and vivid sensory experiences that are interpreted in a non-morbid way. They are different from true hallucinations in that the individual is able to recognize that the experience is an internally generated event.

Understanding the different types of altered perceptual experiences is important in the diagnosis and treatment of various mental health conditions.

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.

Hyponatremia in Psychiatric Patients

Hyponatremia, of low serum sodium, can occur in psychiatric patients due to the disorder itself, its treatment, of other medical conditions. Symptoms include nausea, confusion, seizures, and muscular cramps. Drug-induced hyponatremia is known as the syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH), which results from excessive secretion of ADH and fluid overload. Diagnosis is based on clinically euvolaemic state with low serum sodium and osmolality, raised urine sodium and osmolality. SSRIs, SNRIs, and tricyclics are the most common drugs that can cause SIADH. Risk factors for SIADH include starting a new drug, and treatment usually involves fluid restriction and sometimes demeclocycline.

Understanding Action Potentials in Neurons and Muscle Cells

The membrane potential is a crucial aspect of cell physiology, and it exists across the plasma membrane of most cells. However, in neurons and muscle cells, this membrane potential can change over time. When a cell is not stimulated, it is in a resting state, and the inside of the cell is negatively charged compared to the outside. This resting membrane potential is typically around -70mV, and it is maintained by the Na/K pump, which maintains a high concentration of Na outside and K inside the cell.

To trigger an action potential, the membrane potential must be raised to around -55mV. This can occur when a neurotransmitter binds to the postsynaptic neuron and opens some ion channels. Once the membrane potential reaches -55mV, a cascade of events is initiated, leading to the opening of a large number of Na channels and causing the cell to depolarize. As the membrane potential reaches around +40 mV, the Na channels close, and the K gates open, allowing K to flood out of the cell and causing the membrane potential to fall back down. This process is irreversible and is critical for the transmission of signals in neurons and the contraction of muscle cells.

Deontological (duty-based) ethics prioritize the actions of individuals over the observable practical consequences of those actions.

Ethical theory and principles are important in medical ethics. There are three key ethical theories that have dominated medical ethics: utilitarianism, deontological, and virtue-based. Utilitarianism is based on the greatest good for the greatest number and is a consequentialist theory. Deontological ethics emphasize moral duties and rules, rather than consequences. Virtue ethics is based on the ethical characteristics of a person and is associated with the concept of a good, happy, flourishing life.

More recent frameworks have attempted to reconcile different theories and values. The ‘four principles’ of ‘principlism’ approach, developed in the United States, is based on four common, basic prima facie moral commitments: autonomy, beneficence, non-maleficence, and justice. Autonomy refers to a patient’s right to make their own decisions, beneficence refers to the expectation that a doctor will act in a way that will be helpful to the patient, non-maleficence refers to the fact that doctors should avoid harming their patients, and justice refers to the expectation that all people should be treated fairly and equally.

A fundamental attribution error refers to the tendency to overemphasize dispositional factors and underestimate situational factors when explaining other people’s behavior. The correct term for making false assumptions about other people’s behavior is actually the fundamental attribution error.

Attribution Theory: Understanding How We Explain Events

Attribution theory provides a framework for understanding how individuals explain events in their environment. It examines how people use information to arrive at causal explanations for events and what factors influence their judgments. Fritz Heider first proposed a theory of attribution in 1958.

However, attribution is prone to biases such as the Fundamental Attribution Error (FAE), which overemphasizes dispositional factors over situational causes when making attributions about others’ behavior. The Actor-Observer Bias, on the other hand, undervalues dispositional explanations and overvalued situational explanations of our own behavior. Correspondence bias is the tendency to draw inferences about a person’s unique and enduring dispositions from behaviors that can be entirely explained by the situations in which they occur. Self-serving bias refers to people’s tendency to attribute their successes to internal factors but attribute their failures to external factors. Hostile Attribution Bias (HAB) is an interpretive bias where individuals interpret ambiguous behavior as hostile, leading to aggression. Finally, the False Consensus Effect is the tendency for people to project their way of thinking onto others, assuming that everyone else thinks the same way they do.

Overall, attribution theory helps us understand how people make sense of events in their environment, but it is important to be aware of the biases that can influence our judgments.

Brain Anatomy

The brain is a complex organ with various regions responsible for different functions. The major areas of the cerebrum (telencephalon) include the frontal lobe, parietal lobe, occipital lobe, temporal lobe, insula, corpus callosum, fornix, anterior commissure, and striatum. The cerebrum is responsible for complex learning, language acquisition, visual and auditory processing, memory, and emotion processing.

The diencephalon includes the thalamus, hypothalamus and pituitary, pineal gland, and mammillary body. The thalamus is a major relay point and processing center for all sensory impulses (excluding olfaction). The hypothalamus and pituitary are involved in homeostasis and hormone release. The pineal gland secretes melatonin to regulate circadian rhythms. The mammillary body is a relay point involved in memory.

The cerebellum is primarily concerned with movement and has two major hemispheres with an outer cortex made up of gray matter and an inner region of white matter. The cerebellum provides precise timing and appropriate patterns of skeletal muscle contraction for smooth, coordinated movements and agility needed for daily life.

The brainstem includes the substantia nigra, which is involved in controlling and regulating activities of the motor and premotor cortical areas for smooth voluntary movements, eye movement, reward seeking, the pleasurable effects of substance misuse, and learning.

The half-life of a drug is the time taken for its concentration to fall to one half of its value. Drugs with long half-lives may require a loading dose to achieve therapeutic plasma concentrations rapidly. It takes about 4.5 half-lives to reach steady state plasma levels. Most drugs follow first order kinetics, where a constant fraction of the drug in the body is eliminated per unit time. However, some drugs may follow zero order kinetics, where the plasma concentration of the drug decreases at a constant rate, despite the concentration of the drug. For drugs with nonlinear kinetics of dose-dependent kinetics, the relationship between the AUC of CSS and dose is not linear, and the kinetic parameters may vary depending on the administered dose.

The basal ganglia includes the caudate nucleus.

The Papez Circuit: A Neural Pathway for Emotion

James Papez was the first to describe a neural pathway in the brain that mediates the process of emotion. This pathway is known as the ‘Papez circuit’ and is located on the medial surface of the brain. It is bilateral, symmetrical, and links the cortex to the hypothalamus.

According to Papez, information about emotion passes through several structures in the brain, including the hippocampus, the Mammillary bodies of the hypothalamus, the anterior nucleus of the thalamus, the cingular cortex, and the entorhinal cortex. Finally, the information passes through the hippocampus again, completing the circuit.

The Papez circuit was one of the first descriptions of the limbic system, which is responsible for regulating emotions, motivation, and memory. Understanding the Papez circuit and the limbic system has important implications for understanding and treating emotional disorders such as anxiety and depression.

In a survey conducted by Nock et al.1, which involved interviewing more than 80,000 individuals across 17 countries regarding suicidal behaviors, it was discovered that 60% of individuals who transitioned from suicidal ideation to planning and attempting suicide did so within the first year of experiencing ideation.

Attachment Theory and Harlow’s Monkeys

Attachment theory, developed by John Bowlby, suggests that children have an innate tendency to form relationships with people around them to increase their chance of survival. This attachment is different from bonding, which concerns the mother’s feelings for her infant. Children typically single out a primary caregiver, referred to as the principle attachment figure, from about 1-3 months. The quality of a person’s early attachments is associated with their adult behavior, with poor attachments leading to withdrawn individuals who struggle to form relationships and good attachments leading to socially competent adults who can form healthy relationships.

Bowlby’s attachment model has four stages: preattachment, attachment in the making, clear-cut attachment, and formation of reciprocal attachment. The time from 6 months to 36 months is known as the critical period, during which a child is most vulnerable to interruptions in its attachment. Attachments are divided into secure and insecure types, with insecure types further divided into avoidant and ambivalent types.

Harlow’s experiment with young rhesus monkeys demonstrated the importance of the need for closeness over food. The experiment involved giving the monkeys a choice between two different mothers, one made of soft terry cloth but provided no food and the other made of wire but provided food from an attached baby bottle. The baby monkeys spent significantly more time with their cloth mother than with their wire mother, showing the importance of attachment and closeness in early development.