Differential Diagnosis step by step chapter 1

Question 1

What are the 6 steps of differential diagnosis?

Answer 1

1. Ruling out Malingering and Factitious Disorder
2. Ruling out a substance etiology
3. Rule Out a Disorder Due to Another Medical Condition
4. Determining the specific independent mental disorder(s) (i.e., nonsubstance-induced and not due to another medical condition)
5. Differentiating Adjustment Disorders from the residual Other Specified and Unspecified conditions
6. Establishing the boundary with no mental disorder

Question 2

Step 1 - rule out malingering or factitious disorder

What is Malingering and Factitious Disorder?

Answer 2

The intentional production of false or grossly exaggerated physical or psychological symptoms

Question 3

Step 1

What is the difference between Malingering Factitious Disorder?

Answer 3

Differentiated based on the motivation for the deception
Malingering - motivation for the deceptive behaviour is the achievement of a clearly recognisable goal
Factitious Disorder - deceptive behavior is present even without obvious external rewards

Question 4

Step 1

What are the consequences of patients not being honest regarding the nature or severity of their symptoms?

Answer 4

The clinician’s ability to arrive at an accurate psychiatric diagnosis is compromised

• The important part of diagnosis and psychiatric work depends on patient’s and clinician’s collaborative effort to uncover the nature and cause of the presenting symptoms

Question 5

Step 1

When should clinicians be extra careful (suspicious) in ruling out Malingering and Factitious Disorder?

Answer 5

1) When there are external incentives for a psychiatric diagnosis (e.g. prison settings, forensic evaluations in criminal case…)
2) When patient presents with a collection of symptoms conforming to non-expert perceptions of mental illness rather than a set of symptoms that aligns with clinically recognised psychiatric diagnosis
3) When the nature of the symptoms shifts between clinical encounters
4) When patient has a presentation that mimics that of a role model (e.g. ill close family member)
5) When patient is characteristically manipulative or suggestible

However! Clinicians must be mindful of tendencies they might have toward being either excessively skeptical or excessively gullible

Question 6

Look at the case in picture 1. What is the evidence for step 1? Provide reasoning

Answer 6

Sufficient answer: ‘‘There are reasons to carefully consider the veracity of the reporting by this patient. There may certainly be a motive for this given the circumstances for asking diagnostic consultation. Furthermore, the history gives example of the patient giving false documentation.’’

Insufficient answer: ‘‘There is no information suggesting malingering or factitious disorder.’’

Question 7

Step 2 - rule out substance etiology

What is one of the question to consider in the differential diagnosis process regarding substances?

Answer 7

Whether the presenting symptoms arise from a substance directly affecting the central nervous system (CNS)

Question 8

Step 2

Why is it important to consider substance etiology?

Answer 8

Missing a substance etiology is the single most common diagnostic error made in clinical practice

• particularly problematic because making a correct diagnosis has immediate treatment implications

Question 9

Step 2

What are the 3 tasks of determining substance use disorder?

Answer 9

1. Determine whether the person has been using a substance
2. Determine whether there is an etiological relationship with the psychiatric symptomatology
3. After deciding that a presentation is due to the direct effects of a substance or medication, determine which DSM-5-TR Substance/Medication-Induced Mental Disorder best describes the presentation

Question 10

Step 2 - Task 1

What does the determination whether the person has been using a substance entail?

Answer 10

• Taking careful history and physical examination for signs
• Consulting with family members and obtaining a laboratory analysis of body fluids
  ↪ because substance-abusing individuals are notorious for underestimating their intake

Question 11

Step 2 - Task 1

What is important to remember with patients who use or are exposed to any of a variety of substances (not only drugs of abuse)?

Answer 11

• They can often present with psychiatric symptoms
• Medication-induced psychopathology is common and very often missed, especially in older population and those who take multiple medications
• Toxin exposure should also be considered (occupational hazard)

Question 12

Step 2 - Task 2

Once substance use has been established, what is the next task?

Answer 12

To determine whether there is an etiological relationship with the psychiatric symptomatology

Question 13

Step 2 - Task 2

What are the three possible relationships between substance use and psychiatric symptomatology?

Answer 13

1) Psychiatric symptoms result from the direct effects of the substance on the CNS (resulting in diagnosis of Substance/Medication-induced Mental Disorder)
2) Substance use is a consequence of a primary psychiatric disorder
3) Psychiatric symptoms and substance use are independent

Question 14

Step 2 - Task 2.1 Causal relationship

What should be assessed to determine the causal relationship between substance use and psychiatric symptoms?

Answer 14

1) Temporal relationship
2) Likelihood of substance use causing symptoms
3) Alternative explanations for symptoms

Question 15

Step 2 - Task 2.1.1 Temporal relationship

How can the temporal relationship determine the whether there is a causal relationship between substance use and psychiatric symptoms?

Answer 15

Determine whether there was a period of time when the psychiatric symptoms were present outside the context of substance/medication

• If the onset of the psychopathology clearly precedes the onset of the substance/medication use, then it is likely that a non-substance/medication-induced psychiatric condition is primary and the substance/medication use is secondary (2nd type of relationship)
• If the onset of the substance/medication use clearly and closely precedes the psychopathology, it lends greater credence to the likelihood of a Substance/Medication-Induced Mental Disorder

Question 16

Step 2 - Task 2.1.1 Temporal relationship

Since in clinical practice, it’s very difficult to discern the onset of substance use and psychopathology, what can be another tool to determine whether there is causal relationship?

Answer 16

• Psychiatric symptoms that remit (stop) within 1 month (clinical judgment for timing required) of cessation of acute intoxication, withdrawal, or medication use → Substance/Medication-Induced Mental Disorder
• Persistence of the psychiatric symptomatology for a significant period of time after the cessation of acute withdrawal or severe intoxication or after stopping a medication → psychopathology primary (there are exceptions)

Best to make this determination in a facility where the patient’s access to substances can be controlled and the patient’s psychiatric symptomatology can be serially assessed

Question 17

Step 2 - Task 2.1.1 Temporal relationship

Why should be the 1 month time frame considered with cautious clinical judgment?

Answer 17

Because the 1-month time frame applies to a wide variety of substances and medications with very different pharmacokinetic properties and a wide variety of possible consequent psychopathologies
Additionally, the setting of the diagnosis is important

• substance use treatment setting: want to avoid misdiagnosing a substance-induced disorder as independent so prefer longer absinence period (6-8 weeks)
• psychiatric clinicians may find such a long wait impractical, potentially leading to overdiagnosis of substance-induced disorders and underdiagnosis of independent mental disorders

Hence, the time frame must be applied flexibly, considering the extent, duration, and nature of the substance/medication use

Question 18

Step 2 - Task 2.1.2 Likelihood of substance use causing symptoms

What needs to be considered when determining the likelihood of the substance use causing the psychopathology?

Answer 18

Consider whether the nature, amount, and duration of substance/medication use are consistent with the development of the observed psychiatric symptoms (e.g. a severe and persisting depressed mood following the isolated use of a small amount of cocaine - not consistent with cocaine use)

Question 19

Step 2 - Task 2.1.3 Alternative explanations

What factors should be considered when thinking about alternative causes other than a substance or medication?

Answer 19

• history of many similar episodes not related to substance/medication use
• a strong family history of the particular independent psychiatric disorder
• the presence of physical examination or laboratory findings suggesting that a nonpsychiatric medical condition might be involved

This requires fine clinical judgment to weigh the relative probabilities in these situations

Question 20

Step 2 - Task 2.2 substance use as a consequence of psychopathology

What are indicators for independent psychiatric disorder with secondary substance use?

Answer 20

1. The independent psychiatric disorder occurs first and/or exists at times during the person’s lifetime when they are not using any substance (validity depends on patient’s retrospective reporting so rather also consult with other informants or review past records)
2. Form of self-medication so often individuals with particular psychiatric disorders preferentially choose certain classes of substances (e.g. people with anxiety disorders prefer CNS depressants, i.e. alcohol)

Question 21

Step 2 - Task 2.3 Psychiatric symptoms and substance use are independent

What can complicate the diagnosis of psychiatric disorders in the presence of substance use?

Answer 21

The high prevalence rates of both psychiatric disorders and Substance Use Disorders, leading to potential comorbidity

• even if initially independent, the two might interact to exacerbate each other and complicate overall treatment

Question 22

Step 2 - Task 2.3 Psychiatric symptoms and substance use are independent

What should a clinician do in assessing a patient with both psychiatric symptoms and substance use?

Answer 22

Rule out that one is causing the other

• A lack of a causal relationship in either direction is more likely if there are periods when the psychiatric symptoms occur in the absence of substance use and if the substance use occurs at times unrelated to the psychiatric symptomatology

Question 23

Step 2 - Task 3

What is the last task in step 2 if we decide that a presentation of symptoms is due to the direct effect of a substance or medication?

Answer 23

Determine which DSM-5-TR Substance/Medication-Induced Mental Disorder best describes the presentation
E.g. Specific Substance/Medication-Induced Mental Disorders, Substance Intoxication, and Substance Withdrawal

Question 24

Step 3

What is the third step in the differential diagnosis process?

Answer 24

Rule out a disorder due to another medical condition (that is classified outside the ICD mental disorders chapter)

Question 25

# Step 3 Why is ruling out a nonpsychiatric medical condition crucial in psychiatric diagnosis?

Answer 25

- Many individuals with nonpsychiatric medical conditions have psychiatric symptoms as a complication - Many individuals with psychiatric symptoms have an underlying medica condition - The treatment implications of this differential diagnostic step are also profound - Successful differentiation is crucial in avoiding medical complications and reducing the psychiatric symptomatology

Question 26

# Step 3 Why can be differential diagnoses between another medical condition and psychiatric symptoms difficult?

Answer 26

1. Symptoms of some psychiatric disorders and of many nonpsychiatric medical conditions can be identical 2. Sometimes the first presenting symptoms of a medical condition are psychiatric (e.g., depression preceding other symptoms in pancreatic cancer or a brain tumor) 3. The relationship between the nonpsychiatric medical condition and the psychiatric symptoms may be complicated (flashcard 27) 4. Psychiatric patients are often seen in settings primarily geared toward the identification and treatment of mental disorders in which there may be a lower expectation for, and familiarity with, the diagnosis of medical conditions

Question 27

# Step 3 If the clinician has suspicion that the psychiatric symptoms are a direct physiological effect of nonpsychiatric medical condition, what should they do? How is this called in DSM?

Answer 27

Virtually any psychiatric presentation can be caused by the direct physiological effects of a nonpsychiatric medical condition - not feasible to do all laboratory tests all the time but it's possible to narrow the focus - direct the history, physical examination, and laboratory tests toward the diagnosis of those nonpsychiatric medical conditions that are most commonly encountered and most likely to account for the presenting psychiatric symptoms (e.g. thyroid function tests for depression) Diagnosed in DSM-5-TR as one of the Mental Disorders Due to Another Medical Condition (e.g. Depressive Disorder Due to Hypothyroidism)

Question 28

# Step 3 What are the five possible relationships between nonpsychiatric medical conditions and psychiatric symptoms?

Answer 28

1. Nonpsychiatric medical condition causes psychiatric symptoms through a direct **physiological** **effect on the brain** 2. Nonpsychiatric medical condition causes psychiatric symptoms through a **psychological mechanism** (e.g. depression because of cancer diagnosis) 3. **Medication** for the nonpsychiatric medical condition causes psychiatric symptoms (then diagnosis Medication-Induced Mental Disorder) 4. Psychiatric symptoms **adversely affect** the nonpsychiatric medical condition 5. Psychiatric symptoms and nonpsychiatric medical condition are **coincidental** ## Footnote In real clinical world, several of these relationships may occur simultaneously with a multifactorial etiology

Question 29

# Step 3 - Type 1 relationship What are two clues suggesting that psychopathology is caused by the direct physiological effect of a nonpsychiatric medical condition?

Answer 29

1. Nature of the temporal relationship 2. Atypical symptom pattern, age at onset, or course (e.g. severe weigh loss accompanies relatively mild depression) ## Footnote Nonetheless, establishing the nature of the causal relationship often requires careful evaluation, longitudinal follow-up, and trials of treatment

Question 30

# Step 3 - clue 1 What should be considered when evaluating the temporal relationship between psychiatric symptoms and a nonpsychiatric medical condition?

Answer 30

a) Whether psychiatric symptoms begin following the onset of the medical condition b) Whether severity of symptoms varies with the severity of the medical condition c) Whether symptoms remit when the medical condition resolves When all of these relationships can be demonstrated, a fairly compelling case can be made that the nonpsychiatric medical condition has caused the psychiatric symptoms; however, such a clue does not establish that the relationship is physiological - the temporal covariation could also be due to a psychological reaction to the nonpsychiatric medical condition

Question 31

# Step 3 What must a clinician determine if they conclude that a nonpsychiatric medical condition is responsible for psychiatric symptoms?

Answer 31

Which DSM-5-TR Mental Disorder Due to Another Medical Condition best describes the presentation - E.g. Psychotic Disorder Due to Another Medical Condition, Depressive Disorder Due to Another Medical Condition

Question 32

# Step 4 What is the next step after ruling out substance use and nonpsychiatric medical conditions?

Answer 32

Determine which independent DSM-5-TR mental disorder best accounts for the presenting symptomatology

Question 33

# Step 4 What is the purpose of the decision trees in DSM-5-TR?

Answer 33

Many of the diagnostic groupings in DSM-5-TR are organized around common presenting symptoms and in combination with the decision trees, these facilitate the differential diagnosis among independent mental disorders

Question 34

# Step 4 Once the clinician has selected what appears to be the most likely disorder, what is the next important step?

Answer 34

To review the pertinent differential diagnosis table, “Differential Diagnosis by the Tables,” to ensure that all other possible contenders in the differential diagnosis have been considered and ruled out

Question 35

# Step 5 What is the step 5 in differential diagnosis and why is this step part of the differential diagnosis?

Answer 35

Differentiate Adjustment Disorders From the Residual Other Specified or Unspecified Mental Disorders - Many mental disorder presentations in outpatient and primary care settings do not fit DSM-5-TR criteria or meet severity/duration thresholds. However, if symptoms cause significant distress or impairment and reflect dysfunction in mental functioning, a diagnosis is still warranted—typically as an **Adjustment Disorder** or a residual **Other Specified/Unspecified category**

Question 36

# Step 5 What is the difference between Adjustment Disorder and Other Specified/Unspecified category?

Answer 36

**Adjustment Disorder** - the symptoms have developed as a maladaptive response to a psychosocial stressor **Other Specified/Unspecified category** - stressor is not responsible for the development of the clinically significant symptoms ↪ with the choice of the appropriate residual category depending on which DSM-5-TR diagnostic grouping best covers the symptomatic presentation - The judgment in this step is centered more on whether a stressor is the cause of the symptoms rather than on whether a stressor is present

Question 37

# Step 5 What distinguishes Other Specified Mental Disorder from Unspecified Mental Disorder?

Answer 37

Whether the clinician specifies the reason for not meeting specific disorder criteria - If wants to indicate: the name of the disorder is followed by the reason why the presentation doesn't conform to any of the specific disorder definitions - If doesn't want to indicate: Unspecified Mental disorder

Question 38

# Step 5 - Unspecified mental disorder Why might a clinician decide not to indicate the specific reason why the presentation doesn't conform to any of the specific diagnostic criteria?

Answer 38

- If there is insufficient information to make a more specific diagnosis and the clinician expects that additional information may be forthcoming - If the clinician decides it is in the patient’s best interest not to be specific about the reason

Question 39

# Step 6 What is the final step in establishing a diagnosis according to the DSM-5-TR? Why?

Answer 39

Establish the boundary between a disorder and no mental disorder - Many of the symptoms included in DSM-5-TR are fairly ubiquitous (present everywhere) and are not by themselves indicative of the presence of a mental disorder (e.g. during the course of their lives, most people may experience periods of anxiety)

Question 40

# Step 6 What criterion must be met for a diagnosis of a mental disorder according to DSM-5-TR? What decides the boundary?

Answer 40

Any psychopathology must lead to clinically significant problems in order to warrant a mental disorder diagnosis DSM-V-TR: ''The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning''

Question 41

# Step 6 Why doesn't DSM define the term clinically significant?

Answer 41

The boundary between disorder and normality can be set only by clinical judgment and not by any hard-and-fast rules - The determination is influenced by the cultural context, the setting in which the individual is seen, clinician bias, patient bias, and the availability of resources

Question 42

# Step 6 In clinical mental health settings, what makes a presentation clinically significant? When does it become challenging?

Answer 42

The individual seeking help automatically makes it clinically significant - However, more challenging are situations in which the symptomatic picture is discovered in the course of treating another mental disorder or a nonpsychiatric medical condition ↪ Because of high comorbidity, it's not uncommon

Question 43

# Step 6 What is the general rule regarding comorbid psychiatric presentations?

Answer 43

If it warrants clinical attention and treatment, it is considered clinically significant

Question 44

# Step 6 What is an example of a condition that may impair functioning but does not qualify as a mental disorder?

Answer 44

Uncomplicated Bereavement - It's worthy of clinical attention and should be given a code from the DSM-5-TR chapter “Other Conditions That May Be a Focus of Clinical Attention”

Question 45

What is differential diagnosis?

Answer 45

Choosing a single diagnosis from a group of competing, mutually exclusive diagnoses to best explain a given symptom presentation.

Question 46

What shoud a clinician do if patient presents with symptoms that fit diagnoses that are not mutually exclusive?

Answer 46

The assignment of more than one DSM-5-TR diagnosis to a given patient is both allowed and necessary to adequately describe the presenting symptoms

Question 47

What does comorbidity within diagnostic groupings imply?

Answer 47

Multiple passes through decision trees may be required to cover all possible diagnoses with answering the key questions differently each time, depending on which (e.g. anxiety) symptom is the current focus - A patient with one Anxiety Disorder is more likely to have other comorbid Anxiety Disorders (e.g. Panic Disorder)

Question 48

What is the significance of having multiple DSM-5-TR diagnoses?

Answer 48

It does not imply multiple independent conditions; they are descriptive building blocks that are useful for communicating diagnostic information - Because this is not the only possible relationship...

Question 49

What are the six different relationships between comorbid conditions?

Answer 49

1. Condition A causes condition B 2. Condition B causes condition A 3. An underlying condition C causes both A and B 4. A and B are part of a more complex syndrome 5. Relationship enhanced by definitional overlap 6. Chance co-occurrence The particular nature of these relationships is often very difficult to determine

Question 50

The end! Almost... Now go to the document Differential Diagnosis chapter 1 that I sent in the patients groupchat and read the case example on page 10-14