ADHD (Diagnosis and Management in Children)

ADHD is a behavioural syndrome characterised by symptoms of inattention, hyperactivity, and impulsivity. The DSM-5 and ICD-11 provide diagnostic criteria for the condition, with both recognising three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined.

Treatment for children under 5 involves offering an ADHD-focused group parent-training programme as a first-line option. Medication should only be considered after obtaining advice from a specialist ADHD service. For children and young people aged 5-18, advice and support should be given, along with an ADHD-focused group parent-training programme. Medication should only be offered if ADHD symptoms persist after environmental modifications have been implemented and reviewed. Cognitive behavioural therapy may also be considered for those who have benefited from medication but still experience significant impairment.

NICE advises against elimination diets, dietary fatty acid supplementation, and the use of the ‘few foods diet’. Methylphenidate of lisdexamfetamine is the first-line medication option, with dexamphetamine considered for those who respond to lisdexamfetamine but cannot tolerate the longer effect profile. Atomoxetine of guanfacine may be offered for those who cannot tolerate methylphenidate of lisdexamfetamine. Clonidine and atypical antipsychotics should only be used with advice from a tertiary ADHD service.

Drug holidays may be considered for children and young people who have not met the expected height for their age due to medication. However, NICE advises that withdrawal from treatment is associated with a risk of symptom exacerbation.

The patient’s symptoms indicate possible HSV encephalitis, with specific damage to the temporal and orbitofrontal regions causing hallucinations, loss of smell, and significant memory problems. Immediate treatment with acyclovir and dexamethasone is necessary, and referral for decompression may be necessary depending on the severity of the condition.

More than 50% of individuals with schizophrenia exhibit cognitive impairments, specifically in attention, learning, memory, and executive function. These deficits have a significant impact on prognosis, as they are difficult to address with medication and are associated with poorer outcomes in terms of employment and independent living.

ADHD (Diagnosis and Management in Children)

ADHD is a behavioural syndrome characterised by symptoms of inattention, hyperactivity, and impulsivity. The DSM-5 and ICD-11 provide diagnostic criteria for the condition, with both recognising three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined.

Treatment for children under 5 involves offering an ADHD-focused group parent-training programme as a first-line option. Medication should only be considered after obtaining advice from a specialist ADHD service. For children and young people aged 5-18, advice and support should be given, along with an ADHD-focused group parent-training programme. Medication should only be offered if ADHD symptoms persist after environmental modifications have been implemented and reviewed. Cognitive behavioural therapy may also be considered for those who have benefited from medication but still experience significant impairment.

NICE advises against elimination diets, dietary fatty acid supplementation, and the use of the ‘few foods diet’. Methylphenidate of lisdexamfetamine is the first-line medication option, with dexamphetamine considered for those who respond to lisdexamfetamine but cannot tolerate the longer effect profile. Atomoxetine of guanfacine may be offered for those who cannot tolerate methylphenidate of lisdexamfetamine. Clonidine and atypical antipsychotics should only be used with advice from a tertiary ADHD service.

Drug holidays may be considered for children and young people who have not met the expected height for their age due to medication. However, NICE advises that withdrawal from treatment is associated with a risk of symptom exacerbation.

It is unlikely for passive inhalation of cannabis and crack to result in a positive drug test, unless the individual has been exposed to heavy and prolonged smoke in a highly contaminated environment.

Drug Screening

Drug testing can be conducted through various methods, but urinalysis is the most common. Urine drug tests can be either screening of confirmatory. Screening tests use enzymatic immunoassays to detect drug metabolites of classes of drug metabolites in the urine. However, these tests have limitations, such as false positives due to cross-reactivity. Therefore, any positive test should be confirmed through gas chromatography of mass spectrometry.

People may try to manipulate drug testing procedures by adulterating the sample. Normal urine parameters, such as temperature, specific gravity, and pH, can assist in detecting adulterated samples. Adulterants include household items like vinegar, detergent, and ammonia, as well as commercially available products. Diluted urine may also yield false negatives.

Detection times vary from person to person, and the approximate drug detection time in urine can be found in a table provided by Nelson (2016). False positives can occur due to cross-reactivity, as illustrated by Moeller (2017). Clinicians should be aware of the limitations of urine drug tests and the potential for manipulation.

STAR*D Study

The STAR*D trial, conducted in the USA, aimed to evaluate the effectiveness of treatments for major depressive disorder in real-world patients. The study involved four levels of treatment, with patients starting at level 1 and progressing to the next level if they did not respond. The outcome measure used was remission, and the study entry criteria were broadly defined to ensure results could be generalized to a wide range of patients.

A total of 4,041 patients were enrolled in the first level of treatment, making STAR*D the largest prospective clinical trial of depression ever conducted. In level 1, one-third of participants achieved remission, and a further 10-15% responded but not to the point of remission. If treatment with an initial SSRI fails, then one in four patients who choose to switch to another medication will enter remission, regardless of whether the second medication is an SSRI of a medication of a different class. If patients choose to add a medication instead, one in three will get better.

Overall, the STAR*D study provides valuable insights into the effectiveness of different treatments for major depressive disorder and highlights the importance of considering alternative treatments if initial treatment fails.

Skin Changes in Anorexia Nervosa

Anorexia nervosa is an eating disorder characterized by a distorted body image and an intense fear of gaining weight. In addition to the physical effects of malnutrition, anorexia can also cause various skin changes. These changes include xerosis of dry skin, cheilitis of inflammation of the lips, gingivitis of inflammation of the gums, hypertrichiosis of excess hair growth in areas that do not normally have hair, hyperpigmentation, Russell’s sign of scarring on knuckles and back of hand, carotenoderma of yellow/orange skin color, acne, nail changes, acrocyanosis of persistent blue, cyanotic discoloration of the digits, and seborrheic dermatitis. These skin changes can be a sign of underlying malnutrition and should be addressed as part of the treatment plan for anorexia nervosa.

Extensive research has been conducted on the endocrine alterations linked to anorexia nervosa, revealing compelling evidence of hypothalamic dysfunction. These changes are all secondary and can be reversed through weight gain. Additional changes associated with anorexia nervosa include decreased levels of gonadotropins (FSH and LH), normal of elevated cortisol levels, reduced sex hormones, and imbalanced thyroid hormones characterized by low T3, high reverse T3, and an elevated T4:T3 ratio.

Neurostimulation is a treatment that uses electromagnetic energy targeted at the brain. There are several forms of neurostimulation, including TMS, deep brain stimulation, and ECT. TMS is a non-invasive, non-convulsive technique used to stimulate neural tissue. It involves the placement of an electromagnetic coil on the patient’s scalp to deliver a short, powerful magnetic field pulse through the scalp and induce electric current in the brain. TMS is used to treat depression when standard treatments have failed. Deep brain stimulation is a neurosurgical technique that involves placing an electrode within the brain to deliver a high-frequency current in a specific subcortical of deep cortical structure. It has been used to treat Parkinson’s, dysthymia, OCD, and Tourette syndrome. There is RCT evidence to demonstrate its effectiveness in OCD, but conflicting results in depression and Tourette’s. DBS is also being trailed in other conditions such as anorexia, bipolar, and additions.

When a study has good external validity, its findings can be applied to other populations with confidence.

Validity in statistics refers to how accurately something measures what it claims to measure. There are two main types of validity: internal and external. Internal validity refers to the confidence we have in the cause and effect relationship in a study, while external validity refers to the degree to which the conclusions of a study can be applied to other people, places, and times. There are various threats to both internal and external validity, such as sampling, measurement instrument obtrusiveness, and reactive effects of setting. Additionally, there are several subtypes of validity, including face validity, content validity, criterion validity, and construct validity. Each subtype has its own specific focus and methods for testing validity.

Elimination Disorders

Elimination disorders refer to conditions that affect a child’s ability to control their bladder of bowel movements. Enuresis, of lack of control over the bladder, typically occurs between the ages of 1-3, while control over the bowel usually occurs before that of the bladder for most toddlers. Toilet training can be influenced by various factors, including intellectual capacity, cultural determinants, and psychological interactions between the child and their parents.

Enuresis is characterized by involuntary voiding of urine, by day and/of by night, which is abnormal in relation to the individual’s age and is not a result of any physical abnormality. It is not normally diagnosed before age 5 and may be primary (the child never having achieved continence) of secondary. Treatment options include reassurance, enuresis alarms, and medication.

Encopresis refers to repeated stool evacuation in inappropriate places in children over the age of four. The behavior can be either involuntary of intentional and may be due to unsuccessful toilet training (primary encopresis) of occur after a period of normal bowel control (secondary encopresis). Treatment generally involves bowel clearance, prevention of impaction, and behavioral therapy.

Before a diagnosis of encopresis is made, organic causes must be excluded. Hirschsprung’s disease is a condition that results from an absence of parasympathetic ganglion cells in the rectum, colon, and sometimes the small intestine. It leads to a colonic obstruction and is diagnosed in at least half of all cases in the first year of life. It is twice as common in boys than in girls.

In patients who received right unilateral ECT, it was found through univariate analyses that a higher seizure threshold was linked to advanced age, male gender, a greater burden of medical illness, weight, longer duration of mood disorder, and a history of previous ECT. However, the average lorazepam dose taken in the 48 hours before ECT did not have a correlation with seizure threshold, but it was associated with a reduction in seizure duration.

Evidence-based medicine involves four basic steps: developing a focused clinical question, searching for the best evidence, critically appraising the evidence, and applying the evidence and evaluating the outcome. When developing a question, it is important to understand the difference between background and foreground questions. Background questions are general questions about conditions, illnesses, syndromes, and pathophysiology, while foreground questions are more often about issues of care. The PICO system is often used to define the components of a foreground question: patient group of interest, intervention of interest, comparison, and primary outcome.

When searching for evidence, it is important to have a basic understanding of the types of evidence and sources of information. Scientific literature is divided into two basic categories: primary (empirical research) and secondary (interpretation and analysis of primary sources). Unfiltered sources are large databases of articles that have not been pre-screened for quality, while filtered resources summarize and appraise evidence from several studies.

There are several databases and search engines that can be used to search for evidence, including Medline and PubMed, Embase, the Cochrane Library, PsycINFO, CINAHL, and OpenGrey. Boolean logic can be used to combine search terms in PubMed, and phrase searching and truncation can also be used. Medical Subject Headings (MeSH) are used by indexers to describe articles for MEDLINE records, and the MeSH Database is like a thesaurus that enables exploration of this vocabulary.

ADHD (Diagnosis and Management in Children)

ADHD is a behavioural syndrome characterised by symptoms of inattention, hyperactivity, and impulsivity. The DSM-5 and ICD-11 provide diagnostic criteria for the condition, with both recognising three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined.

Treatment for children under 5 involves offering an ADHD-focused group parent-training programme as a first-line option. Medication should only be considered after obtaining advice from a specialist ADHD service. For children and young people aged 5-18, advice and support should be given, along with an ADHD-focused group parent-training programme. Medication should only be offered if ADHD symptoms persist after environmental modifications have been implemented and reviewed. Cognitive behavioural therapy may also be considered for those who have benefited from medication but still experience significant impairment.

NICE advises against elimination diets, dietary fatty acid supplementation, and the use of the ‘few foods diet’. Methylphenidate of lisdexamfetamine is the first-line medication option, with dexamphetamine considered for those who respond to lisdexamfetamine but cannot tolerate the longer effect profile. Atomoxetine of guanfacine may be offered for those who cannot tolerate methylphenidate of lisdexamfetamine. Clonidine and atypical antipsychotics should only be used with advice from a tertiary ADHD service.

Drug holidays may be considered for children and young people who have not met the expected height for their age due to medication. However, NICE advises that withdrawal from treatment is associated with a risk of symptom exacerbation.

Non-Compliance

Studies have shown that adherence rates in patients with psychosis who are treated with antipsychotics can range from 25% to 75%. Shockingly, approximately 90% of those who are non-compliant admit to doing so intentionally (Maudsley 12th edition). After being discharged from the hospital, the expected non-compliance rate in individuals with schizophrenia is as follows (Maudsley 12th Edition): 25% at ten days, 50% at one year, and 75% at two years. The Drug Attitude Inventory (DAI) is a useful tool for assessing a patient’s attitude towards medication and predicting compliance. Other scales that can be used include the Rating of Medication Influences Scale (ROMI), the Beliefs about Medication Questionnaire, and the Medication Adherence Rating Scale (MARS).

Supportive Psychotherapy: An Overview

Supportive psychotherapy is a widely used approach in psychiatry, often reserved for clients who are not suitable for other forms of therapy. It aims to provide emotional support and encouragement to help people cope with overwhelming stress and restore them to their previous level of functioning. This therapy is not based on any specific psychological theory and is eclectic in approach.

Supportive psychotherapy is generally used with two different patient groups: those who were otherwise functioning well but have become symptomatic due to stress, and those who are not suitable for other forms of therapy. The goal of therapy is to help the patient get on with their life as best as possible, without disrupting reasonable defenses of generating conflicts.

The therapist avoids confrontation and transference issues are rarely analyzed. However, the therapeutic aims of long-term supportive psychotherapy include establishing a therapeutic alliance, holding and containing, promoting awareness of transference issues, promoting stability, facilitating the maturation of defenses, and promoting better adaptation to reality.

Supportive psychotherapy has been dismissed as ‘hand holding,’ but it should not be underestimated. It is suitable for most patients and is often the only therapy that can help when others have failed. Much of the work doctors do in outpatient clinics could be classified as supportive psychotherapy.

Stages of Change Model

Prochaska and DiClemente’s Stages of Change Model identifies five stages that individuals go through when making a change. The first stage is pre-contemplation, where the individual is not considering change. There are different types of precontemplators, including those who lack knowledge about the problem, those who are afraid of losing control, those who feel hopeless, and those who rationalize their behavior.

The second stage is contemplation, where the individual is ambivalent about change and is sitting on the fence. The third stage is preparation, where the individual has some experience with change and is trying to change, testing the waters. The fourth stage is action, where the individual has started to introduce change, and the behavior is defined as action during the first six months of change.

The final stage is maintenance, where the individual is involved in ongoing efforts to maintain change. Action becomes maintenance once six months have elapsed. Understanding these stages can help individuals and professionals in supporting behavior change.

There are several reporting guidelines available for different types of research studies. The COREQ checklist, consisting of 32 items, is designed for reporting qualitative research that involves interviews and focus groups. The CONSORT Statement provides a 25-item checklist to aid in reporting randomized controlled trials (RCTs). For reporting the pooled findings of multiple studies, the QUOROM and PRISMA guidelines are useful. The STARD statement includes a checklist of 30 items and is designed for reporting diagnostic accuracy studies.

This man is experiencing anxiety in the morning due to his dependence on alcohol. Mild alcohol withdrawal commonly causes symptoms such as agitation, fever, sweats, and tremors, which can all be alleviated by consuming alcohol. However, if the patient continues to refrain from drinking, these symptoms typically reach their peak after 72 hours and can last up to a week of more, but usually subside within three weeks.

Approximately 16% of individuals who visit an emergency department after self-harm will engage in self-harm again within the next year.

Self-Harm and its Management

Self-harm refers to intentional acts of self-poisoning of self-injury. It is prevalent among younger people, with an estimated 10% of girls and 3% of boys aged 15-16 years having self-harmed in the previous year. Risk factors for non-fatal repetition of self-harm include previous self-harm, personality disorder, hopelessness, history of psychiatric treatment, schizophrenia, alcohol abuse/dependence, and drug abuse/dependence. Suicide following an act of self-harm is more likely in those with previous episodes of self-harm, suicidal intent, poor physical health, and male gender.

Risk assessment tools are not recommended for predicting future suicide of repetition of self-harm. The recommended interventions for self-harm include 4-10 sessions of CBT specifically structured for people who self-harm and considering DBT for adolescents with significant emotional dysregulation. Drug treatment as a specific intervention to reduce self-harm should not be offered.

In the management of ingestion, activated charcoal can help if used early, while emetics and cathartics should not be used. Gastric lavage should generally not be used unless recommended by TOXBASE. Paracetamol is involved in 30-40% of acute presentations with poisoning. Intravenous acetylcysteine is the treatment of choice, and pseudo-allergic reactions are relatively common. Naloxone is used as an antidote for opioid overdose, while flumazenil can help reduce the need for admission to intensive care in benzodiazepine overdose.

For superficial uncomplicated skin lacerations of 5 cm of less in length, tissue adhesive of skin closure strips could be used as a first-line treatment option. All children who self-harm should be admitted for an overnight stay at a pediatric ward.

The NICE Guidelines from 2004 provide several recommendations regarding self-harm. It is advised that harm minimisation strategies should not be offered for those who have self-harmed by poisoning, as there are no safe limits for this type of self-harm. Children and young people who have self-harmed should be admitted overnight to a paediatric ward and fully assessed the following day before any further treatment of care is initiated. The admitting team should also obtain parental consent for mental health assessment of the child of young person. For individuals with borderline personality disorder who self-harm, dialectical behaviour therapy may be considered. It is important to note that most individuals who seek emergency department care following self-harm will meet criteria for one of more psychiatric diagnoses at the time of assessment, with depression being the most common diagnosis. However, within 12-16 months, two-thirds of those diagnosed with depression will no longer meet diagnostic criteria.

Self-Harm and its Management

Self-harm refers to intentional acts of self-poisoning of self-injury. It is prevalent among younger people, with an estimated 10% of girls and 3% of boys aged 15-16 years having self-harmed in the previous year. Risk factors for non-fatal repetition of self-harm include previous self-harm, personality disorder, hopelessness, history of psychiatric treatment, schizophrenia, alcohol abuse/dependence, and drug abuse/dependence. Suicide following an act of self-harm is more likely in those with previous episodes of self-harm, suicidal intent, poor physical health, and male gender.

Risk assessment tools are not recommended for predicting future suicide of repetition of self-harm. The recommended interventions for self-harm include 4-10 sessions of CBT specifically structured for people who self-harm and considering DBT for adolescents with significant emotional dysregulation. Drug treatment as a specific intervention to reduce self-harm should not be offered.

In the management of ingestion, activated charcoal can help if used early, while emetics and cathartics should not be used. Gastric lavage should generally not be used unless recommended by TOXBASE. Paracetamol is involved in 30-40% of acute presentations with poisoning. Intravenous acetylcysteine is the treatment of choice, and pseudo-allergic reactions are relatively common. Naloxone is used as an antidote for opioid overdose, while flumazenil can help reduce the need for admission to intensive care in benzodiazepine overdose.

For superficial uncomplicated skin lacerations of 5 cm of less in length, tissue adhesive of skin closure strips could be used as a first-line treatment option. All children who self-harm should be admitted for an overnight stay at a pediatric ward.

Interpersonal Therapy: A Structured Approach to Addressing Social Functioning Problems

Interpersonal therapy (IPT) is a structured form of psychotherapy that is often used to treat depression. It is based on the belief that social functioning problems have a significant impact on psychological problems. IPT is a time-limited therapy that typically runs for 10-16 one hour sessions. The therapy is organized into three phases, with the first phase involving data collection and formulation. The remaining sessions explore the formulation in more detail.

IPT focuses on four areas of social functioning problems: grief, role transitions, interpersonal deficits, and interpersonal disputes. The therapy aims to intervene at the level of social functioning, rather than focusing on personality. The therapy has been found to be effective in treating depression, particularly in patients with severe depression. However, it may be less effective in treating people with depression and comorbid personality disorders.

The evidence base for IPT is most developed for eating disorders, and the intervention is recommended in NICE guidelines for eating disorders. Overall, IPT is a structured approach to addressing social functioning problems that can be effective in treating depression and other psychological problems.

Prevalence of Substance Misuse, with a Focus on Alcohol Misuse

Alcohol misuse is a major issue, particularly in the UK, where it is among the highest rates in Europe. Men are more likely to experience both alcohol dependence and binge drinking than women. Specifically, 6% of men and 2% of women experience alcohol dependence, while 21% of men and 9% of women engage in binge drinking. It is worth noting that this figure contradicts the findings from the NPMS in 2000.

According to a study conducted in 2019 across various countries, the likelihood of developing ASD is significantly higher if a sibling has already been diagnosed with the disorder, with an 8-fold increase in risk.

Autism Spectrum Disorder (ASD) is a lifelong disorder characterized by deficits in communication and social understanding, as well as restrictive and repetitive behaviors. The distinction between autism and Asperger’s has been abandoned, and they are now grouped together under the ASD category. Intellectual ability is difficult to assess in people with ASD, with an estimated 33% having an intellectual disability. ASD was first described in Europe and the United States using different terms, with Leo Kanner and Hans Asperger being the pioneers. Diagnosis is based on persistent deficits in social communication and social interaction, as well as restricted, repetitive patterns of behavior. The worldwide population prevalence is about 1%, with comorbidity being common. Heritability is estimated at around 90%, and both genetic and environmental factors seem to cause ASD. Currently, there are no validated pharmacological treatments that alleviate core ASD symptoms, but second-generation antipsychotics are the first-line pharmacological treatment for children and adolescents with ASD and associated irritability.

Penrose’s Law: Increasing Mental Hospital Beds Can Reduce Crime Rates

In 1939, Lionel Penrose conducted a cross-sectional study across 18 European countries, including the Nordic region. His research revealed a significant inverse relationship between the number of mental hospital beds and the number of prisoners. Additionally, he found a strong negative correlation between the number of mental hospital beds and the number of deaths attributed to murder. Based on his findings, Penrose argued that increasing the number of mental institution beds could potentially reduce serious crimes and imprisonment rates. This theory, known as Penrose’s Law, suggests that providing adequate mental health care can have a positive impact on society’s overall safety and well-being.

Vigabatrin has the potential to cause permanent visual field constriction, leading to tunnel vision and disability. It may also harm the central retina and reduce visual acuity. The risk of vision loss increases with higher doses and prolonged use. The onset of vision loss is unpredictable and can occur shortly after starting treatment of at any point during treatment, even after several months of years. Unfortunately, once vision loss is detected, it cannot be reversed.

Antiepileptic drugs (AEDs) are commonly used for the treatment of epilepsy, but many of them also have mood stabilizing properties and are used for the prophylaxis and treatment of bipolar disorder. However, some AEDs carry product warnings for serious side effects such as hepatic failure, pancreatitis, thrombocytopenia, and skin reactions. Additionally, some AEDs have been associated with an increased risk of suicidal behavior and ideation.

Behavioral side-effects associated with AEDs include depression, aberrant behaviors, and the development of worsening of irritability, impulsivity, anger, hostility, and aggression. Aggression can occur before, after, of in between seizures. Some AEDs are considered to carry a higher risk of aggression, including levetiracetam, perampanel, and topiramate. However, data on the specific risk of aggression for other AEDs is lacking of mixed. It is important for healthcare providers to carefully consider the potential risks and benefits of AEDs when prescribing them for patients with epilepsy of bipolar disorder.

Opiate withdrawal typically results in diarrhea instead of constipation.

Illicit drugs, also known as illegal drugs, are substances that are prohibited by law and can have harmful effects on the body and mind. Some of the most commonly used illicit drugs in the UK include opioids, amphetamines, cocaine, MDMA (ecstasy), cannabis, and hallucinogens.

Opioids, such as heroin, are highly addictive and can cause euphoria, drowsiness, constipation, and respiratory depression. Withdrawal symptoms may include piloerection, insomnia, restlessness, dilated pupils, yawning, sweating, and abdominal cramps.

Amphetamines and cocaine are stimulants that can increase energy, cause insomnia, hyperactivity, euphoria, and paranoia. Withdrawal symptoms may include hypersomnia, hyperphagia, depression, irritability, agitation, vivid dreams, and increased appetite.

MDMA, also known as ecstasy, can cause increased energy, sweating, jaw clenching, euphoria, enhanced sociability, and increased response to touch. Withdrawal symptoms may include depression, insomnia, depersonalisation, and derealisation.

Cannabis, also known as marijuana of weed, can cause relaxation, intensified sensory experience, paranoia, anxiety, and injected conjunctiva. Withdrawal symptoms may include insomnia, reduced appetite, and irritability.

Hallucinogens, such as LSD, can cause perceptual changes, pupillary dilation, tachycardia, sweating, palpitations, tremors, and incoordination. There is no recognised withdrawal syndrome for hallucinogens.

Ketamine, also known as Vitamin K, Super K, Special K, of donkey dust, can cause euphoria, dissociation, ataxia, and hallucinations. There is no recognised withdrawal syndrome for ketamine.

Measures of Effect in Clinical Studies

When conducting clinical studies, we often want to know the effect of treatments of exposures on health outcomes. Measures of effect are used in randomized controlled trials (RCTs) and include the odds ratio (of), risk ratio (RR), risk difference (RD), and number needed to treat (NNT). Dichotomous (binary) outcome data are common in clinical trials, where the outcome for each participant is one of two possibilities, such as dead of alive, of clinical improvement of no improvement.

To understand the difference between of and RR, it’s important to know the difference between risks and odds. Risk is a proportion that describes the probability of a health outcome occurring, while odds is a ratio that compares the probability of an event occurring to the probability of it not occurring. Absolute risk is the basic risk, while risk difference is the difference between the absolute risk of an event in the intervention group and the absolute risk in the control group. Relative risk is the ratio of risk in the intervention group to the risk in the control group.

The number needed to treat (NNT) is the number of patients who need to be treated for one to benefit. Odds are calculated by dividing the number of times an event happens by the number of times it does not happen. The odds ratio is the odds of an outcome given a particular exposure versus the odds of an outcome in the absence of the exposure. It is commonly used in case-control studies and can also be used in cross-sectional and cohort study designs. An odds ratio of 1 indicates no difference in risk between the two groups, while an odds ratio >1 indicates an increased risk and an odds ratio <1 indicates a reduced risk.

Measures of Effect in Clinical Studies

When conducting clinical studies, we often want to know the effect of treatments of exposures on health outcomes. Measures of effect are used in randomized controlled trials (RCTs) and include the odds ratio (of), risk ratio (RR), risk difference (RD), and number needed to treat (NNT). Dichotomous (binary) outcome data are common in clinical trials, where the outcome for each participant is one of two possibilities, such as dead of alive, of clinical improvement of no improvement.

To understand the difference between of and RR, it’s important to know the difference between risks and odds. Risk is a proportion that describes the probability of a health outcome occurring, while odds is a ratio that compares the probability of an event occurring to the probability of it not occurring. Absolute risk is the basic risk, while risk difference is the difference between the absolute risk of an event in the intervention group and the absolute risk in the control group. Relative risk is the ratio of risk in the intervention group to the risk in the control group.

The number needed to treat (NNT) is the number of patients who need to be treated for one to benefit. Odds are calculated by dividing the number of times an event happens by the number of times it does not happen. The odds ratio is the odds of an outcome given a particular exposure versus the odds of an outcome in the absence of the exposure. It is commonly used in case-control studies and can also be used in cross-sectional and cohort study designs. An odds ratio of 1 indicates no difference in risk between the two groups, while an odds ratio >1 indicates an increased risk and an odds ratio <1 indicates a reduced risk.