AP Psychology · Lesson 2

Categories of psychological disorders

Know Know it

Anxiety disorders involve fear or worry out of proportion to real danger. In generalized anxiety disorder, a person has hard-to-control worry about many everyday matters on most days for six months or more. In panic disorder, a person has repeated, unexpected panic attacks (sudden intense fear with a pounding heart, chest tightness and shortness of breath) plus ongoing worry about more attacks. A specific phobia is intense fear of one object or situation, and social anxiety disorder is intense fear of being judged by others.

In obsessive-compulsive disorder, a person has obsessions (unwanted, intrusive thoughts) and compulsions (repeated acts done to ease the anxiety the thoughts bring). Posttraumatic stress disorder can follow a traumatic event, with intrusive memories or nightmares, avoidance of reminders, negative changes in mood and high arousal, lasting more than a month.

Major depressive disorder involves at least two weeks of low mood or lost interest, with symptoms such as changes in sleep or appetite, fatigue and feelings of worthlessness. Persistent depressive disorder is a milder but longer-lasting low mood, for two years or more in adults. Bipolar disorders include manic or milder hypomanic episodes (high or irritable mood, high energy, little need for sleep, racing thoughts, risky choices), usually alongside depressive episodes.

Schizophrenia is a psychotic disorder. Positive symptoms add experiences not usually present: hallucinations (perceiving things that are not there), delusions (fixed false beliefs) and disorganized speech. Negative symptoms reflect a loss: flat affect, little speech and low motivation. One biological explanation, the dopamine hypothesis, links positive symptoms to overactive dopamine activity.

Other groups include dissociative disorders, such as dissociative amnesia and dissociative identity disorder (two or more distinct identity states, a rare and debated diagnosis); neurodevelopmental disorders that begin in childhood, such as ADHD and autism spectrum disorder; feeding and eating disorders, such as anorexia nervosa (severe restriction and very low weight) and bulimia nervosa (cycles of bingeing and purging); and personality disorders, lasting and inflexible patterns such as antisocial personality disorder (disregard for others' rights, little remorse) and borderline personality disorder (unstable relationships, self-image and emotions).

Disorders are explained on several levels. Genes, brain structure and neurotransmitters form one level. Thinking is another: researchers link depression to an explanatory style that treats bad events as internal (my fault), stable (it will last) and global (it affects everything), and to learned helplessness, a concept from animal research in which repeated uncontrollable events lead to giving up. Culture shapes how symptoms are shown and understood.

Telling similar disorders apart
DisorderKey featureWhat it is not
Generalized anxiety disorderOngoing worry about many everyday thingsNot sudden attacks out of the blue
Panic disorderRepeated unexpected panic attacks and fear of moreNot fear tied to one object
Specific phobiaIntense fear of one object or situationNot worry spread across many topics
Posttraumatic stress disorderSymptoms that follow a traumatic eventNot anxiety without a triggering event
Bipolar disorderManic or hypomanic episodesNot depression alone

Trap Schizophrenia is not a split personality

Schizophrenia involves a break from reality, such as hallucinations and delusions. Having two or more distinct identity states is dissociative identity disorder, a separate diagnosis.

Worked example Easy

Which of these is a negative symptom of schizophrenia?

  1. Hearing voices that no one else in the room can hear
  2. A face that shows almost no emotionAnswer
  3. Believing a TV host is sending secret personal messages
  4. Speech that jumps between unrelated topics

How to solve it

  1. Positive symptoms add something; negative symptoms take something away.
  2. Voices, false beliefs and jumbled speech are all added.
  3. A face with almost no emotion is a loss, so it is the negative symptom.

Why each choice is right or wrong

  • A. Incorrect. Hearing voices no one else hears is a hallucination, which adds an experience and so is a positive symptom.
  • B. Correct. Flat affect, showing little emotion, is a loss of typical expression and so is a negative symptom.
  • C. Incorrect. Believing a TV host sends secret messages is a delusion, a positive symptom that adds a false belief.
  • D. Incorrect. Speech jumping between unrelated topics is disorganized speech, which counts as a positive symptom.

Explain Explain it

Task verbs: identify, explain, compare

To tell disorders apart, compare three things: what the symptoms are, what sets them off, and how long they last. A diagnosis rests on the whole pattern, not on one symptom.

Worked example Hard

Over the past six months, Kenji has had four sudden episodes in which his heart races, his chest tightens and he fears he is dying. Two came while he was relaxing at home watching a movie. Between episodes he feels fine, but he checks his pulse often and has stopped driving alone in case one happens again.

Which diagnosis best fits Kenji's pattern?

  1. Generalized anxiety disorder
  2. Specific phobia
  3. Panic disorderAnswer
  4. Social anxiety disorder

How to solve it

  1. The episodes are sudden, intense and come without a clear trigger.
  2. Between them he worries about more episodes and changes his behavior.
  3. Unexpected attacks plus fear of more attacks is panic disorder.

Why each choice is right or wrong

  • A. Incorrect. Generalized anxiety disorder is steady worry about many everyday things, and Kenji feels fine between sudden episodes.
  • B. Incorrect. A specific phobia is fear of one object or situation, but Kenji's episodes came at random, even at home.
  • C. Correct. Repeated unexpected attacks plus worry and changed behavior to avoid another attack mark panic disorder.
  • D. Incorrect. Social anxiety disorder is fear of being judged by others, but two episodes came while Kenji was relaxing at home.

Compare Your turn

Compare major depressive disorder and bipolar disorder: name one kind of episode both can include and one kind of episode only bipolar disorder includes, with an example sign of it.

Write it, then compare. Nothing you type here is saved or graded.

Compare with a model answer

A full answer does this

  • Names depressive episodes as something both disorders can include
  • Names manic or hypomanic episodes as found only in bipolar disorder and gives one sign of them

Model answer

Both disorders can include depressive episodes, with weeks of low mood or lost interest in things the person used to enjoy. Only bipolar disorder includes manic or hypomanic episodes, such as days of high energy with little need for sleep.

Apply Apply it

Practice these topics. AP Practice questions on exactly what this lesson covers, with an explanation for every answer.