Core psychiatry vocabulary in plain English: mood, thought and behavior disorders — defined for nursing and pre-med students.
Last updated: September 22, 2026
Psychiatry is the medical specialty devoted to the diagnosis and care of mental, emotional and behavioral disorders. Its vocabulary spans the signs and symptoms clinicians observe, the disorders of mood, thought and perception, and the terms used to describe altered states of consciousness. Mastering these terms is essential groundwork for nursing programs, pre-med coursework and any clinical role involving mental health care.
| Term | Definition |
|---|---|
| Affect | The outward, observable expression of a person's emotional state. |
| Mood | A person's sustained, subjective emotional state over time. |
| Anxiety | A feeling of excessive worry, tension or unease, often about anticipated events. |
| Depression | A mental health condition marked by persistent sadness, loss of interest and reduced energy. |
| Mania | A state of abnormally elevated mood, energy and activity. |
| Delusion | A fixed, false belief that persists despite clear evidence to the contrary. |
| Hallucination | A sensory perception that occurs without an external stimulus, such as hearing voices that are not present. |
| Anhedonia | The reduced ability to feel pleasure from activities that were previously enjoyable. |
| Insomnia | Persistent difficulty falling asleep or staying asleep. |
| Dissociation | A disruption in the normal integration of memory, identity, perception or consciousness. |
| Phobia | An intense, irrational fear of a specific object, activity or situation. |
| Obsession | A recurrent, intrusive thought or urge that causes distress. |
| Compulsion | A repetitive behavior or mental act performed to reduce distress caused by an obsession. |
| Schizophrenia | A chronic psychiatric disorder characterized by disturbances in thinking, perception and behavior, including delusions and hallucinations. |
| Bipolar disorder | A psychiatric condition marked by alternating episodes of depression and mania. |
| Panic attack | A sudden episode of intense fear accompanied by physical symptoms such as a racing heart and shortness of breath. |
| Post-traumatic stress disorder | A psychiatric condition that can develop after exposure to a traumatic event, marked by intrusive memories, avoidance and heightened arousal. |
| Personality disorder | A long-standing pattern of inner experience and behavior that deviates from cultural expectations and causes distress or impairment. |
| Catatonia | A state of abnormal movement and behavior, ranging from immobility to excessive, purposeless activity. |
| Delirium | An acute, fluctuating disturbance of attention and awareness, often with confusion. |
| Psychosis | A mental state characterized by a loss of contact with reality, often involving delusions or hallucinations. |
| Somatization | The expression of psychological distress through physical symptoms. |
| Psychomotor agitation | Excessive, purposeless physical movement driven by inner tension. |
| Flight of ideas | A rapid flow of thoughts that shift abruptly from one topic to another. |
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Start learning free →Psychiatry vocabulary lets clinicians, students and patients describe mood, thought and behavior disorders precisely — from psychosis to panic attacks — which is essential for accurate documentation and communication in mental health care.
Yes. This vocabulary is core to US health programs — nursing school and NCLEX prep, pre-med, and medical assistant training. MediLearn lets you drill these terms with quizzes and flashcards using spaced repetition.
A mental health condition marked by persistent sadness, loss of interest and reduced energy.
A repetitive behavior or mental act performed to reduce distress caused by an obsession.
An acute, fluctuating disturbance of attention and awareness, often with confusion.