Unit 23: Psychological Disorders and Classification
Where the line falls between an ordinary struggle and a diagnosable disorder, and what the leading candidates for causing each disorder actually are.
6 topics · 18 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
Defining a Psychological Disorder
- How it worksHow does the DSM define a disorder using distress, dysfunction, and deviation from a cultural norm, rather than any single test?
- Going furtherWhat happens to a diagnosis's boundary when the exact same symptoms are evaluated against a different cultural context?
- Common mistakeWhy isn't every unusual or uncomfortable psychological state automatically a disorder?
Your turn1 of 2
Two people show the exact same intense sadness and withdrawal, one grieving a recent death and the other with no identifiable trigger at all, and only the second is typically classified as having a disorder. A student assumes there must be some single objective test, like a blood test, that draws this line. How does the DSM actually define a disorder using distress, dysfunction, and deviation from a cultural norm, rather than any single test?Anxiety Disorders and Phobias
- How it worksHow does classical conditioning explain a specific phobia forming from a single frightening pairing between a stimulus and a threat?
- Worked exampleFind why phobias of snakes and heights are far more common than phobias of cars, even though cars cause vastly more injuries.
- Common mistakeWhy isn't a phobia simply a matter of willpower that a person could shake off if they tried harder?
Your turn1 of 2
Someone gets stuck in a malfunctioning elevator for twenty minutes and afterward develops a paralyzing fear of elevators that persists for years, triggered by just one bad experience. A student assumes fear this intense and long-lasting should require many repeated frightening experiences to develop, not just a single one. How does classical conditioning explain a specific phobia forming from a single frightening pairing between a stimulus and a threat?Depression and Its Diagnostic Criteria
- How it worksHow does the diathesis-stress model explain depression emerging from a biological vulnerability combined with a triggering life stressor?
- Common mistakeWhy isn't depression simply a matter of a person choosing to think more negatively?
- Going furtherWhat happens to depression's symptom pattern when a genetically vulnerable person is never exposed to a major stressor at all?
Your turn1 of 2
Two people carry a similar genetic vulnerability to depression, but only one of them develops the disorder after experiencing a major life stressor, while the other, who never experiences a comparable stressor, never develops it. A student assumes genetic vulnerability alone should be enough to fully explain who develops depression. How does the diathesis-stress model explain depression emerging from a biological vulnerability combined with a triggering life stressor?Schizophrenia and Psychosis
- How it worksHow does an excess of dopamine activity in certain brain pathways relate to the positive symptoms of schizophrenia, like hallucinations?
- Going furtherWhat happens to the relative weight of genes versus environment as a cause once you compare identical twins where only one has schizophrenia?
- Common mistakeWhy isn't schizophrenia the same thing as having multiple personalities?
Your turn1 of 2
Identical twins show schizophrenia concordance of about 50 percent, while fraternal twins show only about 16 percent. Find how many percentage points higher the identical twin concordance rate is.Autism Spectrum Disorder
- How it worksHow does difficulty with theory of mind help explain some of the social communication challenges seen in autism spectrum disorder?
- Common mistakeWhy isn't autism spectrum disorder caused by childhood vaccines, despite the retracted study that once claimed it was?
- Going furtherWhat happens to a diagnosis's presentation across the autism spectrum, from someone who needs significant daily support to someone who lives independently?
Your turn1 of 2
A child with autism spectrum disorder struggles to predict what another person is thinking or intending, contributing to some of their social communication challenges. A student assumes social difficulty in autism must come from a general dislike of other people rather than anything cognitive. How does difficulty with theory of mind help explain some of the social communication challenges seen in autism spectrum disorder?The Diathesis-Stress Model
- How it worksHow does the diathesis-stress model combine an underlying vulnerability with an environmental trigger to explain who develops a disorder and who doesn't?
- Worked exampleFind why someone with high genetic vulnerability needs only a small stressor to develop a disorder, while low vulnerability might withstand a far larger one.
- Ties togetherHow does the diathesis-stress model connect the reaction range that genes set for a trait to the onset of a psychological disorder?
Your turn1 of 2
A person with high genetic vulnerability crosses their threshold for developing a disorder after a stressor of intensity 3. A person with low genetic vulnerability can withstand a much larger stressor of intensity 16 before reaching that same threshold. Find how many times larger a stressor the low-vulnerability person can withstand.