Misconception Repair Lab

Common shortcuts that lead learners astray in F20-F29 classification, and how to check for them instead.

• Believing hyperkinetic disorder is caused by poor parenting or diet

  "If the parents just disciplined him more consistently (or cut out sugar), this wouldn't be happening."

• Treating old age itself as an explanation for cognitive decline

  "They're old — some forgetfulness is normal at that age."

• Treating a single difficult or unusual trait as a personality disorder

  "This person's way of relating to others is unusual and causes friction, so this must be a personality disorder."

• Treating any excessive or intense fear as a phobic disorder

  "This person is clearly scared of something specific, so it must be a phobia."

• Applying F19 whenever more than one substance is mentioned

  "More than one substance is involved, so it must be F19."

• Treating any co-occurrence of mood and psychosis as schizoaffective disorder

  "There's psychosis and some mood change here, so this must be schizoaffective disorder."

• Treating any regular use of a psychoactive substance as automatic dependence

  "They use it every day, so they must be dependent on it."

• Treating any sexual difficulty as a sexual dysfunction disorder

  "This person had trouble with sex, so it must be a sexual dysfunction disorder."

• Believing autism is caused by cold or inadequate parenting

  "The parents seem distant, so that must be why the child doesn't engage socially."

• Equating the baby blues with a puerperium-associated mental disorder

  "She's tearful and moody after having the baby, so this is a postpartum disorder."

• Treating bedwetting or soiling as a moral failing or deliberate misbehaviour

  "He's old enough to know better, so he must just be doing it on purpose."

• Treating the behavioural-impairment fourth character as a severity marker

  "There's a serious behavioural problem here too, so this must be a more severe grade of intellectual disability."

• Classifying borderline intellectual functioning as F70

  "Their scores are below average and they're struggling at school, so this is a mild intellectual disability."

• Assuming bulimia nervosa requires a low body weight

  "This person's weight is normal, so it can't be an eating disorder."

• Treating long duration alone as sufficient to classify a chronic mood pattern as a full episode

  "This has been going on for years and is clearly affecting her life, so it must be a real depressive episode."

• Diagnosing an attachment disorder from behaviour alone, without the required caregiving history

  "She's overly friendly with strangers, so that's an attachment disorder."

• Treating any confusion in an older adult as dementia

  "They're confused and elderly, so it must be their dementia."

• Assuming dissociative or conversion symptoms are consciously feigned

  "There's no medical explanation for this, so they must be making it up."

• Treating any fixed false belief as automatically schizophrenia

  "There's a fixed false belief here, so this must be schizophrenia."

• Mistaking a developmentally normal childhood fear for F93

  "The child is scared and upset, so that's an emotional disorder."

• Assuming persistent, hard-to-stop substance use always implies dependence

  "He can't stop using it even though he's been told to, so this must be dependence."

• Assuming any intentionally produced or feigned symptom is malingering

  "They're deliberately faking or exaggerating symptoms, so they must be after something — this is malingering."

• Classifying a single, rationally gain-motivated act as an F63 impulse disorder

  "They gambled / took something that wasn't theirs, so this is a pathological gambling or stealing disorder."

• Assuming bereavement context automatically excludes (or automatically confirms) a depressive episode

  "It's understandable — she just lost her husband, so of course she's low. It's not a real depressive episode."

• Treating any harm from substance use as automatic dependence

  "It's caused a problem, so it must be dependence."

• Treating an informal 'high-functioning' label as meaning no real impairment or as an ICD-10 classification

  "This person is high-functioning, so it must be Asperger syndrome / a milder subtype / not really a significant impairment."

• Ignoring duration and course

  "This looks severe, so it must be the most serious category — schizophrenia."

• Using F99 as a convenient default for any brief or incomplete-looking vignette

  "This case doesn't give me much to go on, so I'll just call it F99."

• Classifying distress about one's own sexual orientation as an F66 disorder

  "They're distressed about their own sexual orientation and wish it were different, so this fits the classification for distress about one's orientation."

• Using an IQ score alone to assign an F70-F73 severity grade

  "The test score falls in this range, so the classification is whichever grade matches that range."

• Classifying a documented later-onset personality change as a lifelong personality disorder

  "Their personality is rigid and causing them problems now, so this is a personality disorder."

• Treating any skill deficit alongside lower general ability as automatically 'specific'

  "The child struggles with reading and has a lower general ability, so this must be a specific reading disorder on top of that."

• Assuming mild intellectual disability means no real support is needed

  "It's the mildest grade, so this person is basically fine and doesn't need much support."

• Conflating sleep terrors and nightmares

  "It was a scary thing that happened during sleep, so it's a nightmare."

• Mistaking OCD's intrusive thoughts for a psychotic symptom

  "This thought is so strange or disturbing, it must indicate psychosis."

• Choosing from one dramatic symptom

  "If there's a hallucination or a delusion, it must be schizophrenia."

• Reaching for a residual category (F28/F29) instead of doing the classification work

  "This case doesn't obviously fit a named category, so it must be 'other' or 'unspecified.'"

• Treating recurrence of depression, or ordinary better days, as evidence of bipolarity

  "She has good days too, so it's probably bipolar."

• Diagnosing childhood autism when the history shows a regression, not a from-birth pattern

  "The child now shows autism-like social and communication difficulties, so this is childhood autism."

• Assessing a shared delusion in isolation, without asking about the relationship

  "This person has a fixed false belief, so I should classify their delusion on its own merits."

• Treating a single defiant or antisocial episode as sufficient for a conduct disorder

  "He hit another student, so that's conduct disorder."

• Treating any single manic episode as automatically bipolar

  "He's manic, so it's bipolar."

• Diagnosing a specific developmental disorder without ruling out inadequate opportunity

  "The child is behind on this specific skill, so this must be a specific developmental disorder."

• Labelling any single odd trait or one-off unusual moment as F21

  "This person is described as quirky or eccentric, so that sounds like F21."

• Believing Tourette syndrome requires involuntary swearing (coprolalia)

  "There's no swearing mentioned, so it can't be Tourette syndrome."

• Treating a long-standing trait as an active episode (or vice versa)

  "This person has always been strange, so it's just how they are" — or the reverse: "This is strange, so it must be a new illness."

• Defaulting to a somatoform classification for unexplained physical symptoms

  "No cause has been found for these symptoms, so it must be somatoform."

• Using unspecified mood disorder as a convenient default

  "I'm not sure exactly which type this is, so I'll just call it unspecified."

• Assuming every withdrawal state carries the same medical danger

  "Withdrawal is withdrawal — if it's distressing, it must be dangerous."

• Diagnosing generalized anxiety disorder from a short, recent episode of worry

  "This person is very anxious and worried, so it must be generalized anxiety disorder."