Lecture 19: What Happens When Things Go Wrong: Mental Illness, Part II

What this lecture covers

This lecture continues the course's unit on psychopathology, asking what counts as mental illness and surveying four major categories: schizophrenia, anxiety disorders, dissociative disorders, and personality disorders. It follows directly from Part I's discussion of how to define mental illness at all, and closes by briefly opening the topic of therapy, which the next and final lecture picks up.

After watching, you should be able to describe the main symptoms and proposed causes of schizophrenia, distinguish the major anxiety disorders, explain what makes dissociative identity disorder controversial, and describe how psychologists think about antisocial personality disorder (psychopathy).

Key ideas

• Defining mental illness: the lecture treats serious mental illness as illness in the medical sense, since it consistently impairs functioning and people who recover from it do not choose to return to it.
• Schizophrenia: a disorder of "split from reality," not split personality, marked by positive symptoms (hallucinations, delusions, disorganized speech and behavior) and the negative symptom of blunted emotion and thought.
• Genetic and environmental risk: identical twins of schizophrenics have about a 50% concordance rate, showing genetics matter but cannot fully explain the disorder; proposed environmental triggers include birth trauma, viral infection, and stressful family environments.
• Anxiety disorders: include generalized anxiety disorder, phobias (better explained by "preparedness theory," an evolved sensitivity to ancestrally dangerous objects, than by simple conditioning), and obsessive-compulsive disorder.
• Dissociative disorders: a spectrum from dissociative amnesia and dissociative fugue to dissociative identity disorder, the last of which is scientifically controversial due to its uneven distribution across countries and therapists.
• Personality disorders: patterns of personality extreme enough to be classified as illness, including antisocial personality disorder (psychopathy), marked by lack of empathy, impulsivity, and difficulty relating to others.
• Comorbidity: people can have more than one disorder at once, and some disorders (such as depression and anxiety) commonly occur together.

Walkthrough

Identifying mental illness (0:00)

The lecture opens by stressing the scale and personal relevance of mental illness, noting an estimate that about half of college graduates will experience a mental illness serious enough to require treatment. It works through the philosophical difficulty of defining mental illness, contrasting the historical view of mental illness as demonic possession or as a label used to ostracize social deviants (citing the historical classification of homosexuality as an illness, and dissidents labeled mentally ill in authoritarian states) with the modern medical view, in which real mental illness consistently harms functioning and people who recover from it do not choose to return to it.

Schizophrenia (11:30)

Schizophrenia affects about 1% of the population and is defined as a "split from reality," not multiple personalities. The lecture details the four positive symptoms, hallucinations (most often auditory), delusions (including "ideas of reference," the belief that events revolve around oneself), disorganized speech, and disorganized behavior, alongside the negative symptom of blunted affect and thought. It covers three subtypes (paranoid, catatonic, disorganized) and reviews evidence for genetic risk (about 50% concordance in identical twins) alongside proposed environmental triggers such as birth-season effects, viral infection, toxoplasmosis exposure, and stressful family environments, cautioning that cause and effect between family stress and schizophrenia is hard to disentangle. The older dopamine theory of schizophrenia is presented as partial at best, since it does not explain negative symptoms or structural brain differences.

Anxiety disorders (24:51)

This section covers generalized anxiety disorder, marked by persistent, uncontrollable worry with physical symptoms, and possibly linked to childhood trauma producing lasting hyper-vigilance. Phobias are discussed next: simple conditioning does not explain why some objects (like snakes) provoke common phobias despite no bad personal experience with them, while genuinely dangerous modern experiences (like car crashes) often do not produce phobias. "Preparedness theory" is offered as a better account, proposing humans evolved heightened sensitivity to objects that were dangerous in an ancestral environment. Obsessive-compulsive disorder rounds out the section: intrusive, irrational thoughts (often about contamination or religious guilt) lead to compulsive behaviors like washing or checking, and the disorder responds well to medications affecting serotonin.

Question and answer on schizophrenia and anxiety disorders (30:35)

Student questions address the distinction between OCD and Tourette's syndrome (Tourette's involves involuntary tics rather than obsessive thoughts), whether disorders can co-occur (yes, some are "comorbid," such as depression and anxiety), where ordinary superstition shades into OCD, whether schizophrenics are generally dangerous (statistically they are more often victims than aggressors), and whether medication effects are permanent (generally not, though medication can help someone stabilize enough to build coping skills).

Dissociative identity disorders (35:02)

Dissociative disorders involve a separation from parts of one's memory or identity. The lecture notes that mild dissociative experiences are common and normal, then distinguishes three more severe types: dissociative amnesia (memory loss following a traumatic event), dissociative fugue (memory loss combined with adopting a new identity), and dissociative identity disorder, historically called multiple personality disorder. Dissociative identity disorder is presented as scientifically controversial: fewer than a quarter of psychiatrists surveyed believe it is a genuine, distinct disorder, partly because diagnosed cases rose sharply in the United States from the 1930s to the 1980s and vary enormously by therapist, suggesting therapist suggestion may shape or even produce the presentation in some patients.

Personality disorders and antisocial personality disorder (44:58)

Personality disorders are described as personality patterns extreme enough to impair functioning, including narcissistic, avoidant, dependent, histrionic, borderline, and paranoid personality disorders. The lecture spends more time on antisocial personality disorder, or psychopathy, marked by selfishness, impulsivity, and a lack of empathy or loyalty. It notes that most murderers, including mass murderers, are not clinically mentally ill, while some serial killers show a range of different underlying conditions. The lecture raises the open question of whether psychopathy should count as an illness at all, since many psychopaths do not seek treatment and some may be highly functional or successful without ever being identified as psychopaths.

Opening the topic of therapy (54:33)

In the closing minutes, the lecture briefly introduces the history of therapy, noting that historical treatments for mental illness were frequently harsh or ineffective, from torture and banishment to later medical treatments of limited success. This sets up next lecture's discussion of which modern therapies actually work.

Before you watch

• Review Part I of this two-part topic, "What Happens When Things Go Wrong: Mental Illness, Part I," which lays out the definitional questions this lecture builds on.
• Recall the earlier lecture material on memory and amnesia (including Korsakoff syndrome and patient H.M.), since dissociative amnesia is compared to those cases here.

Check your understanding

1. Why is schizophrenia not the same as "split personality," and what is the difference between a hallucination and a delusion?
2. What evidence suggests schizophrenia has both a genetic and an environmental component?
3. How does "preparedness theory" explain the pattern of common versus rare phobias better than a simple conditioning account?
4. What evidence makes dissociative identity disorder scientifically controversial?
5. Why does the lecture suggest that psychopathy raises a harder question about whether something should count as a mental illness?