The ‘strange situation’ has been utilized to depict different attachment styles exhibited by infants, with contributions from Bowlby’s observations of primate and human attachment behavior, Bateman’s work on psychotherapeutic models in personality disorder, Freud’s structural theory of the unconscious, and Jung’s exploration of archetypes and the collective unconscious.

To encourage patients to express themselves freely, doctors use various techniques such as validation, confrontation, clarification, facilitation, and open-ended questions. Validation involves making patients feel more comfortable by normalizing their thoughts, feelings, of behaviors. Confrontation involves pointing out something that the patient may be missing of denying. Clarification is used to clarify something that the patient has said. Facilitation involves using verbal and non-verbal cues to encourage patients to continue sharing. Open-ended questions are used to prompt patients to respond in their own words, rather than with a simple yes or no answer.

Differential Diagnosis for a Patient with Temporal Lobe Epilepsy

Temporal lobe epilepsy, also known as complex partial seizures, is characterized by an aura of abdominal symptoms followed by altered consciousness and behavior. This episodic condition can occur rapidly. The presenting symptoms of this patient suggest an acute confusional state, ruling out antibiotic-induced psychosis, which is associated with ongoing antibiotic treatment. Delirium tremens, a severe form of alcohol withdrawal, is also unlikely. Early onset dementia cannot be associated with this presentation due to insufficient information. A differential diagnosis is necessary to determine the underlying cause of the patient’s symptoms.

Amantadine and QTc Prolongation

Amantadine is a medication used to treat Parkinson’s disease and influenza. It has been associated with QTc prolongation, which can increase the risk of Torsades de points. Therefore, caution should be exercised when prescribing amantadine to patients with risk factors for QT prolongation. If a patient is already taking amantadine and develops a prolonged QTc interval, the medication should be discontinued and an alternative treatment considered. It is important to monitor the QTc interval in patients taking amantadine, especially those with risk factors for QT prolongation.

The critical period for development of attachment and social skills is between 6 and 36 months of age. During this time, infants and toddlers are particularly sensitive to their caregivers’ responses and interactions, which can shape their emotional and social development. This period is crucial for establishing secure attachments and developing social skills that will influence their relationships throughout their lives.

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.

Medical Imaging Techniques

There are several medical imaging techniques used to examine the organs and tissues in the body. Magnetic resonance imaging (MRI) uses a strong magnetic field to create detailed images of the structures in the body. It is commonly used to exclude other cerebral pathologies in dementia investigation.

Positron emission tomography (PET) is a nuclear medicine imaging technique that uses radiation to produce three-dimensional, colour images of the functional processes within the human body. It is used to study existing conditions in the body and also how it is developing.

Single-photon emission computed tomography (SPECT) scan with ioflupane iodine injection, also known as DAT scan, helps to identify dopamine deficiency in the brain to rule out Parkinson’s dementia and Lewy body dementia.

Computerised tomography (CT) scan uses x-rays and a computer to create detailed images of the inside of the body. It helps to identify injuries of any growth in the different parts of the body. Although it could be used in dementia investigation, it is not the preferred modality as per NICE.

Ultrasound uses high frequency sounds to visualise soft tissues in the body. However, it is not used for investigations of the head.

Pharmacokinetics is the study of how drugs are affected by the body. This includes how drugs are absorbed into the bloodstream, distributed throughout the body, metabolized into different forms, and eliminated from the body. The acronym ADME is often used to remember these processes. Absorption refers to the transportation of the drug from the site of administration to the bloodstream. Hydrophobic drugs are absorbed better than hydrophilic ones. Distribution refers to the movement of the drug from the bloodstream to other areas of the body. Metabolism involves the conversion of the drug into different forms, often to make it more easily excreted by the kidneys. This process occurs in two phases, involving reduction of hydrolysis in phase 1 and conjugation in phase 2. Excretion refers to the elimination of the drug from the body, which mainly occurs through the kidneys and biliary system.

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.

Clifton Assessment Procedure (CAPE) is a valuable tool for evaluating the quality of life, cognitive impairments, and physical dependency levels in elderly individuals. It is used to identify areas of unmet needs and can be administered in both hospital and community settings. The assessment takes approximately 15-25 minutes to complete and comprises two scales: the cognitive assessment scale and the behavior rating scale. The cognitive assessment scale evaluates orientation, basic cognition, and psychomotor performance, while the behavior rating scale assesses physical dependency and behavioral problems. The CAPE can differentiate between organic brain disease and functional psychiatric disorders and predict the likelihood of hospital discharge. It is commonly used to determine the most appropriate placement for elderly individuals.

Mini Mental State Exam (MMSE)

The Mini Mental State Exam (MMSE) was developed in 1975 by Folstein et al. Its original purpose was to differentiate between organic and functional disorders, but it is now mainly used to detect and track the progression of cognitive impairment. The exam is scored out of 30 and is divided into seven categories: orientation to place and time, registration, attention and concentration, recall, language, visual construction, and attention to written command. Each category has a possible score, and the total score can indicate the severity of cognitive impairment. A score equal to or greater than 27 indicates normal cognition, while scores below this can indicate severe, moderate, of mild cognitive impairment. The MMSE is a useful tool for detecting and tracking cognitive impairment.

Mental Age and IQ

The concept of mental age (MA) was introduced by Alfred Binet in 1905. It involves administering a series of tests to a person of child, which are then ranked according to the age at which people are expected to complete them. The mental age can be used to calculate the intelligence quotient (IQ) using the formula: IQ = MA/CA x 100, where CA is the chronological age. An IQ of 100 indicates that the mental and chronological ages are equal. IQ tends to remain stable throughout life. The Stanford-Binet test was the first IQ test, while the WAIS-IV (Wechsler Adult Intelligence Scale) is the most commonly used IQ test today.

Understanding the Volume of Distribution in Pharmacology

The volume of distribution (Vd) is a crucial concept in pharmacology that helps determine how a drug distributes in the body. It is also known as the apparent volume of distribution, as it is an abstract volume. The Vd indicates whether a drug concentrates in the plasma of spreads out in the body. Drugs that are highly polar tend to stay in central compartments such as the plasma, resulting in a low Vd. Conversely, drugs that are more lipid-soluble are distributed widely, such as in fat, resulting in a high Vd.

The Vd is calculated by dividing the amount of drug in the body by the concentration in the plasma. Clinically, the Vd is used to determine the loading dose of a drug required for a desired blood concentration and to estimate blood concentration in the treatment of overdose. The units of Vd are in volume.

The apparent volume of distribution is dependent on the drug’s lipid of water solubility, plasma protein binding, and tissue binding. Plasma protein binding affects the Vd, as drugs that bind to plasma proteins like albumin have a smaller apparent volume of distribution. This is because they are extracted from plasma and included in drug concentration measurements, which can give a misleading impression of their volume of distribution. Understanding the Vd is essential in pharmacology to ensure the safe and effective use of drugs.

Aphasia is a language impairment that affects the production of comprehension of speech, as well as the ability to read of write. The areas involved in language are situated around the Sylvian fissure, referred to as the ‘perisylvian language area’. For repetition, the primary auditory cortex, Wernicke, Broca via the Arcuate fasciculus (AF), Broca recodes into articulatory plan, primary motor cortex, and pyramidal system to cranial nerves are involved. For oral reading, the visual cortex to Wernicke and the same processes as for repetition follows. For writing, Wernicke via AF to premotor cortex for arm and hand, movement planned, sent to motor cortex. The classification of aphasia is complex and imprecise, with the Boston Group classification and Luria’s aphasia interpretation being the most influential. The important subtypes of aphasia include global aphasia, Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, anomic aphasia, transcortical motor aphasia, and transcortical sensory aphasia. Additional syndromes include alexia without agraphia, alexia with agraphia, and pure word deafness.

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.

Aneuploidy: Abnormal Chromosome Numbers

Aneuploidy refers to the presence of an abnormal number of chromosomes, which can result from errors during meiosis. Typically, human cells have 23 pairs of chromosomes, but aneuploidy can lead to extra of missing chromosomes. Trisomies, which involve the presence of an additional chromosome, are the most common aneuploidies in humans. However, most trisomies are not compatible with life, and only trisomy 21 (Down’s syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome) survive to birth. Aneuploidy can result in imbalances in gene expression, which can lead to a range of symptoms and developmental issues.

Compared to autosomal trisomies, humans are more able to tolerate extra sex chromosomes. Klinefelter’s syndrome, which involves the presence of an extra X chromosome, is the most common sex chromosome aneuploidy. Individuals with Klinefelter’s and XYY often remain undiagnosed, but they may experience reduced sexual development and fertility. Monosomies, which involve the loss of a chromosome, are rare in humans. The only viable human monosomy involves the X chromosome and results in Turner’s syndrome. Turner’s females display a wide range of symptoms, including infertility and impaired sexual development.

The frequency and severity of aneuploidies vary widely. Down’s syndrome is the most common viable autosomal trisomy, affecting 1 in 800 births. Klinefelter’s syndrome affects 1-2 in 1000 male births, while XYY syndrome affects 1 in 1000 male births and Triple X syndrome affects 1 in 1000 births. Turner syndrome is less common, affecting 1 in 5000 female births. Edwards syndrome and Patau syndrome are rare, affecting 1 in 6000 and 1 in 10,000 births, respectively. Understanding the genetic basis and consequences of aneuploidy is important for diagnosis, treatment, and genetic counseling.

It is important to provide education to patients who are prescribed MAOIs regarding the dietary restrictions that must be followed in order to avoid a hypertensive crisis.

MAOIs: A Guide to Mechanism of Action, Adverse Effects, and Dietary Restrictions

First introduced in the 1950s, MAOIs were the first antidepressants introduced. However, they are not the first choice in treating mental health disorders due to several dietary restrictions and safety concerns. They are only a treatment option when all other medications are unsuccessful. MAOIs may be particularly useful in atypical depression (over eating / over sleeping, mood reactivity).

MAOIs block the monoamine oxidase enzyme, which breaks down different types of neurotransmitters from the brain: norepinephrine, serotonin, dopamine, as well as tyramine. There are two types of monoamine oxidase, A and B. The MOA A are mostly distributed in the placenta, gut, and liver, but MOA B is present in the brain, liver, and platelets. Selegiline and rasagiline are irreversible and selective inhibitors of MAO type B, but safinamide is a reversible and selective MAO B inhibitor.

The most common adverse effects of MAOIs occurring early in treatment are orthostatic hypotension, daytime sleepiness, insomnia, and nausea; later common effects include weight gain, muscle pain, myoclonus, paraesthesia, and sexual dysfunction.

Pharmacodynamic interactions with MAOIs can cause two types of problem: serotonin syndrome (mainly due to SSRIs) and elevated blood pressure (caused by indirectly acting sympathomimetic amines releasers, like pseudoephedrine and phenylephrine). The combination of MAOIs and some TCAs appears safe. Only those TCAs with significant serotonin reuptake inhibition (clomipramine and imipramine) are likely to increase the risk of serotonin syndrome.

Tyramine is a monoamine found in various foods, and is an indirect sympathomimetic that can cause a hypertensive reaction in patients receiving MAOI therapy. For this reason, dietary restrictions are required for patients receiving MAOIs. These restrictions include avoiding matured/aged cheese, fermented sausage, improperly stored meat, fava of broad bean pods, and certain drinks such as on-tap beer. Allowed foods include fresh cottage cheese, processed cheese slices, fresh packaged of processed meat, and other alcohol (no more than two bottled or canned beers of two standard glasses of wine, per day).

The phenomenon of morbid jealousy can lead to the partner seeking out another relationship as a result. This illustrates that delusions do not always have to be based on factual inaccuracies, but rather on the individual’s interpretation of insufficient evidence. In the case of morbid jealousy, the evidence of something as minor as wrinkled towels can be enough to trigger irrational thoughts and behaviors.

Serotonin syndrome may sometimes result in increased levels of CPK.

Serotonin Syndrome and Neuroleptic Malignant Syndrome are two conditions that can be difficult to differentiate. Serotonin Syndrome is caused by excess serotonergic activity in the CNS and is characterized by neuromuscular abnormalities, altered mental state, and autonomic dysfunction. On the other hand, Neuroleptic Malignant Syndrome is a rare acute disorder of thermoregulation and neuromotor control that is almost exclusively caused by antipsychotics. The symptoms of both syndromes can overlap, but there are some distinguishing clinical features. Hyper-reflexia, ocular clonus, and tremors are more prominent in Serotonin Syndrome, while Neuroleptic Malignant Syndrome is characterized by uniform ‘lead-pipe’ rigidity and hyporeflexia. Symptoms of Serotonin Syndrome usually resolve within a few days of stopping the medication, while Neuroleptic Malignant Syndrome can take up to 14 days to remit with appropriate treatment. The following table provides a useful guide to the main differentials of Serotonin Syndrome and Neuroleptic Malignant Syndrome.

Formication refers to the sensation of movement under the skin, which can be associated with cocaine abuse and is commonly referred to as the cocaine bug. Autoscopic hallucinations occur when an individual perceives their own body as being projected into external space. Delirium tremens, a symptom of alcohol withdrawal, can cause visual hallucinations such as dark shadows of rats, often appearing as Lilliputian figures.

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.

The main purpose of the ‘serial sevens’ is to evaluate an individual’s ability to focus and maintain attention. It also has a secondary function of assessing memory to some degree.

Mini Mental State Exam (MMSE)

The Mini Mental State Exam (MMSE) was developed in 1975 by Folstein et al. Its original purpose was to differentiate between organic and functional disorders, but it is now mainly used to detect and track the progression of cognitive impairment. The exam is scored out of 30 and is divided into seven categories: orientation to place and time, registration, attention and concentration, recall, language, visual construction, and attention to written command. Each category has a possible score, and the total score can indicate the severity of cognitive impairment. A score equal to or greater than 27 indicates normal cognition, while scores below this can indicate severe, moderate, of mild cognitive impairment. The MMSE is a useful tool for detecting and tracking cognitive impairment.

Movement Disorders: Key Features

Movement disorders refer to a range of conditions that affect voluntary muscle movements. These disorders can be caused by various factors, including neurological conditions, medication side effects, and metabolic imbalances. The following table outlines some of the key features of common movement disorders:

Akinesia: Absence of loss of control of voluntary muscle movements, often seen in severe Parkinson’s disease.

Bradykinesia: Slowness of voluntary movement, a core symptom of Parkinson’s disease.

Akathisia: Subjective feeling of inner restlessness, often caused by antipsychotic medication use.

Athetosis: Continuous stream of slow, flowing, writhing involuntary movements, often seen in cerebral palsy, stroke, and Huntington’s disease.

Chorea: Brief, quasi-purposeful, irregular contractions that appear to flow from one muscle to the next, often seen in Huntington’s disease and Wilson’s disease.

Dystonia: Involuntary sustained of intermittent muscle contractions that cause twisting and repetitive movements, abnormal postures, of both.

Dyskinesia: General term referring to problems with voluntary movements and the presence of involuntary movements, often drug-induced.

Myoclonus: A sequence of repeated, often non-rhythmic, brief shock-like jerks due to sudden involuntary contraction of relaxation of one of more muscles.

Parkinsonism: Syndrome characterized by tremor, rigidity, and bradykinesia.

Tic: Sudden, repetitive, non-rhythmic, stereotyped motor movement of vocalization involving discrete muscle groups, often seen in Tourette’s syndrome.

Tremor: Involuntary, rhythmic, alternating movement of one of more body parts, often seen in essential tremor, Parkinson’s disease, and alcohol withdrawal.

Hemiballismus: Repetitive, but constantly varying, large amplitude involuntary movements of the proximal parts of the limbs, often seen in stroke and traumatic brain injury.

Stereotypies: Repetitive, simple movements that can be voluntarily suppressed, often seen in autism and intellectual disability.

It is important to consider the underlying conditions and factors that may contribute to movement disorders in order to properly diagnose and treat these conditions.

Abnormal Motor Behaviours Associated with Utilization Behaviour

Utilization behaviour (UB) is a condition where patients exhibit exaggerated and inappropriate motor responses to environmental cues and objects. This behaviour is automatic and instrumentally correct, but not contextually appropriate. For instance, a patient may start brushing their teeth when presented with a toothbrush, even in a setting where it is not expected. UB is caused by frontal lobe lesions that result in a loss of inhibitory control.

Other motor abnormalities associated with UB include imitation behaviour, where patients tend to imitate the examiner’s behaviour, and the alien hand sign, where patients experience bizarre hand movements that they cannot control. Manual groping behaviour is also observed, where patients automatically manipulate objects placed in front of them. The grasp reflex, which is normal in infants, should not be present in children and adults. It is an automatic tendency to grip objects of stimuli, such as the examiner’s hand.

Environmental Dependency Syndrome is another condition associated with UB. It describes deficits in personal control of action and an overreliance on social and physical environmental stimuli to guide behaviour in a social context. For example, a patient may start commenting on pictures in an examiner’s office, believing it to be an art gallery.

The Nuremberg Code is a set of ethical principles for human experimentation that emerged from the Nuremberg trials after World War II. It includes guidelines such as obtaining informed consent, avoiding harm to participants, and not conducting experiments that may result in death.

The Helsinki Declaration, established by the World Medical Association, is another set of ethical principles for human research. It has been amended several times since its adoption in 1964 and provides guidelines for conducting research with human subjects.

The Declaration of Geneva is a statement of a physician’s commitment to the humanitarian goals of medicine. It was created as a revision of the Hippocratic oath and has been amended and revised over time.

The Nightingale Pledge is a statement of ethical principles for the nursing profession. It outlines the responsibilities and commitments of nurses to their patients and the healthcare system.

Priapism: A Painful and Persistent Erection

Priapism is a condition characterized by a prolonged and painful erection, which can occur in males and even in the clitoris. Although rare, certain medications such as antipsychotics and antidepressants have been known to cause priapism. The primary mechanism behind this condition is alpha blockade, although other mechanisms such as serotonin-mediated pathways have also been suggested. Some of the drugs most commonly associated with priapism include Trazodone, Chlorpromazine, and Thioridazine. Treatment involves the use of alpha-adrenergic agonists, which can be administered orally of injected directly into the penis. Priapism is a serious condition that can lead to complications such as penile amputation, although such cases are extremely rare.

Tricyclic antidepressants are known to cause various side effects, which can be attributed to their mechanisms of action. These include antimuscarinic effects, which can lead to dry mouth and urinary retention, antihistaminergic effects, which can cause weight gain and drowsiness, antiadrenergic effects, which can result in postural hypotension, sexual dysfunction, and cognitive impairment, and antiserotonergic effects, which can lead to weight gain. Additionally, tricyclic antidepressants can cause cardiotoxicity and reduce the seizure threshold due to their membrane stabilizing effects. Other important side effects of these drugs include arrhythmias and ECG changes, black tongue, tremor, altered liver function tests, paralytic ileus, and neuroleptic malignant syndrome. Black hairy tongue, a harmless condition where the tongue appears black and hairy due to elongated filiform papillae, is also a possible side effect of tricyclic antidepressants.

If a person has mild to moderate kidney impairment, they are in stage 3a of chronic kidney disease. It is recommended to avoid using amisulpride and sulpiride if the person already has kidney failure.

Renal Impairment and Psychotropic Drugs

The following table provides recommendations for drug treatment in patients with renal impairment, based on the Maudsley 14th guidelines. When a new drug treatment is required, the suggestions below should be followed.

Drug Group Recommendation

Antipsychotics: It is recommended to avoid sulpiride and amisulpride. Otherwise, no agent is clearly preferable to another. For first-generation antipsychotics, haloperidol (2-6 mg/day) is the best choice. For second-generation antipsychotics, olanzapine (5mg/day) is the best choice.

Antidepressants: No agent is clearly preferable to another. Reasonable choices include sertraline (although there is poor efficacy data in renal disease), citalopram (with care over QTc prolongation), and fluoxetine (with care over long half-life).

Mood stabilizers: Lithium is nephrotoxic and contraindicated in severe renal impairment. Otherwise, no agent is clearly preferable to another. Valproate of lamotrigine are suggested.

Anxiolytics: No agent is clearly preferable to another. Lorazepam and zopiclone are suggested.

Anti-dementia drugs: No agent is clearly preferable to another. Rivastigmine is suggested.

Prion Diseases

Prion diseases are a group of rare and fatal neurodegenerative disorders that affect humans and animals. These diseases are caused by abnormal proteins called prions, which can cause normal proteins in the brain to fold abnormally and form clumps. This leads to damage and death of brain cells, resulting in a range of symptoms such as dementia, movement disorders, and behavioral changes.

Some of the most well-known prion diseases in humans include Creutzfeldt-Jakob disease, Kuru, Gerstman-Straussler-Scheinker syndrome, and Fatal Familial Insomnia. Creutzfeldt-Jakob disease is the most common prion disease in humans, and it can occur sporadically, genetically, of through exposure to contaminated tissue. Kuru is a rare disease that was once prevalent in Papua New Guinea, and it was transmitted through cannibalism. Gerstman-Straussler-Scheinker syndrome is a rare genetic disorder that affects the nervous system, while Fatal Familial Insomnia is a rare inherited disorder that causes progressive insomnia and other neurological symptoms.

Despite extensive research, there is currently no cure for prion diseases, and treatment is mainly supportive. Prevention measures include avoiding exposure to contaminated tissue and practicing good hygiene.

The heritability estimate does not provide any information about specific individuals.

Heritability: Understanding the Concept

Heritability is a concept that is often misunderstood. It is not a measure of the extent to which genes cause a condition in an individual. Rather, it is the proportion of phenotypic variance attributable to genetic variance. In other words, it tells us how much of the variation in a condition seen in a population is due to genetic factors. Heritability is calculated using statistical techniques and can range from 0.0 to 1.0. For human behavior, most estimates of heritability fall in the moderate range of .30 to .60.

The quantity (1.0 – heritability) gives the environment ability of the trait. This is the proportion of phenotypic variance attributable to environmental variance. The following table provides estimates of heritability for major conditions:

Condition Heritability estimate (approx)
ADHD 85%
Autism 70%
Schizophrenia 55%
Bipolar 55%
Anorexia 35%
Alcohol dependence 35%
Major depression 30%
OCD 25%

It is important to note that heritability tells us nothing about individuals. It is a population-level measure that helps us understand the relative contributions of genetic and environmental factors to a particular condition.

The question pertains to a classic case of atypical depression, which is best treated with phenelzine, a MAOI. While imipramine and other TCAs have some evidence for treating atypical depression, they are not as effective as MAOIs. Nowadays, SSRIs are commonly used as a first-line treatment, but they have a weaker evidence base compared to MAOIs and TCAs. Vortioxetine is a new antidepressant that has complex effects on the 5HT system, but it has not been studied for its efficacy in treating atypical depression. Similarly, venlafaxine has not been studied for this indication either.