Psychological disorder
Also known as: mental disorder, mental illness
A psychological disorder is a pattern of thoughts, feelings, or behaviors that is clinically significant, causes distress or impairment, and reflects a dysfunction in mental functioning. Diagnosis in the United States follows the criteria set out in the DSM-5.
Psychologists identify a disorder by asking whether behavior is maladaptive — whether it interferes with daily functioning — rather than whether it is merely unusual. Four criteria are commonly applied together: deviance from cultural norms, personal distress, dysfunction in work or relationships, and danger to self or others. No single criterion is sufficient on its own, and cultural context matters, since a behavior considered pathological in one society may be ordinary in another.
Classification in the United States uses the Diagnostic and Statistical Manual of Mental Disorders, currently the DSM-5 and its 2022 text revision, the DSM-5-TR, which lists specific criteria for each disorder and groups them into categories including anxiety disorders, depressive and bipolar disorders, obsessive-compulsive and related disorders, trauma- and stressor-related disorders, schizophrenia spectrum and other psychotic disorders, dissociative disorders, feeding and eating disorders, and personality disorders. The World Health Organization's ICD serves the same purpose internationally.
Explanations draw on several perspectives at once. The dominant framework is the biopsychosocial model, which holds that biological factors (genetics, neurotransmitter function, brain structure), psychological factors (learning history, cognition, coping style), and social factors (stress, poverty, culture, support networks) jointly produce disorder. The related diathesis-stress model says an inherited or acquired vulnerability produces symptoms only when environmental stress activates it. Labeling carries real consequences, since diagnostic terms shape both self-concept and social stigma.
AP Psychology covers this material in the mental and physical health unit, where you are expected to explain and classify psychological disorders and describe their treatments. The MCAT psychological and social foundations section covers the same disorders under individual influences on behavior, with more emphasis on their biological correlates.
Key takeaways
- A psychological disorder involves maladaptive thoughts, feelings, or behaviors that cause distress or impairment.
- Deviance, distress, dysfunction, and danger are the criteria commonly used together to identify disorder.
- The DSM-5 provides the standard diagnostic criteria and categories used in the United States.
- The biopsychosocial model explains disorders through combined biological, psychological, and social factors.
- The diathesis-stress model holds that an underlying vulnerability produces symptoms when stress activates it.