Mental Status Exam & Descriptive Psychopathology
Every descriptor is a clue — read the pattern, name the disorder
Structure of the exam
What the MSE records. The mental status exam is the psychiatric physical exam, a record of what is observed during the interview in a fixed order: appearance, behavior (psychomotor activity, eye contact), speech (rate, volume, articulation, pressure), mood, affect, thought process, thought content, perception, cognition, insight, and judgment. Speech describes how words come out; thought process describes how ideas connect. Thought content always includes direct questions about suicidal and homicidal ideation.
Mood versus affect. Mood is the patient's sustained emotional state, quoted in their own words ("I feel empty"). Affect is the emotion the clinician sees, described by range (full, restricted, blunted, flat), stability (labile when it shifts rapidly), and congruence with mood and content. Flat affect suggests negative symptoms of schizophrenia (parkinsonian masked facies can mimic it); lability suggests mania, delirium, intoxication, or pseudobulbar affect after stroke, ALS, or MS; incongruent affect, such as laughing while describing a death, is typical of schizophrenia.
Thought process
| Term | What you hear | Typical setting |
|---|---|---|
| Circumstantiality | Excess detail and detours, but the question is eventually answered | Anxiety, obsessive-compulsive personality; can be normal |
| Tangentiality | Drifts to related topics and never returns | Psychosis, mania |
| Flight of ideas | Rapid, pressured jumps with followable links (puns, rhymes, distractions) | Mania |
| Loose associations | Logical links between ideas lost (derailment) | Schizophrenia |
| Word salad | Incoherent string of words | Severe psychosis |
| Clang associations | Words chosen by sound or rhyme | Mania, schizophrenia |
| Neologisms | Invented words | Schizophrenia |
| Perseveration | Same answer repeated despite new questions | Frontal lobe injury, dementia |
| Thought blocking | Speech halts mid-sentence; thread lost | Schizophrenia |
Patients may explain thought blocking as thought withdrawal, the belief that an outside force removed their thoughts.
Thought content
Delusions. A delusion is a fixed, false belief held despite clear contrary evidence and not explained by culture or religion. Persecutory delusions (being followed, poisoned, plotted against) are the most common; grandiose delusions typify mania; erotomanic patients believe a higher-status person secretly loves them. Nihilistic (Cotard) delusions, that one is dead or one's organs have rotted, appear in psychotic depression, where refusal to eat makes ECT urgent. Somatic delusions involve bodily defects or infestation (delusional parasitosis); delusions of reference read personal messages into neutral events such as TV broadcasts; thought insertion, withdrawal, and broadcasting are classic for schizophrenia.
Overvalued ideas and obsessions. An overvalued idea is an unreasonable, strongly held belief that the patient can concede might be wrong, such as body-shape preoccupation in anorexia or a perceived flaw in body dysmorphic disorder. An obsession is an intrusive, unwanted, ego-dystonic thought recognized as the product of one's own mind and resisted or neutralized, as in OCD. Harm obsessions (images of stabbing one's baby) provoke horror and avoidance rather than action; in thought insertion, the thoughts are believed to come from outside.
Perception
Hallucinations are perceptions without an external stimulus, and the sensory modality points toward the cause.
| Modality | Think first | Clue |
|---|---|---|
| Auditory | Schizophrenia, mood disorder with psychotic features | Voices commenting or conversing; clear sensorium |
| Visual | Delirium, intoxication or withdrawal, Lewy body dementia | Fluctuating attention; well-formed people or animals in Lewy body |
| Tactile | Alcohol withdrawal, cocaine, amphetamines | Formication: bugs crawling under the skin |
| Olfactory, gustatory | Temporal lobe seizure aura | Brief, stereotyped; may precede automatisms |
| Hypnagogic, hypnopompic | Normal; narcolepsy if frequent | At sleep onset or waking; with cataplexy, sleep paralysis |
Illusions are misinterpretations of a real stimulus (a coat on a chair seen as an intruder) and are common in delirium and dim light. Well-formed visual hallucinations in an older adult with vision loss and intact insight suggest Charles Bonnet syndrome.
Depersonalization and derealization. Depersonalization is feeling detached from one's own body, thoughts, or actions, as if watching oneself; derealization is the sense that surroundings are unreal, foggy, or dreamlike. Reality testing stays intact, which separates both from psychosis. They occur in panic attacks, PTSD, sleep deprivation, cannabis or hallucinogen use, and depersonalization/derealization disorder.
Cognition, insight, and clinical use
Cognition. Assess level of consciousness, orientation, attention (serial 7s, spelling WORLD backward, months backward), memory (3-word recall), and, when indicated, a screen such as the MoCA or MMSE. Inattention with fluctuating consciousness is the core of delirium, whereas early Alzheimer disease impairs memory with attention preserved.
Insight and judgment. Insight is awareness of being ill and needing treatment; it is poor in psychosis, mania, and anosognosia. Judgment is the capacity to make sound decisions and is best inferred from the patient's actual recent behavior.
Suspect a medical or substance cause before diagnosing primary psychosis when there is disorientation or fluctuating consciousness, visual, tactile, or olfactory hallucinations, abrupt onset, first onset in later life, or abnormal vital signs or neurologic signs. Work up with glucose, electrolytes, CBC, TSH, B12, HIV, syphilis serology, urine toxicology, a medication review, and imaging or EEG as indicated.
Typical next steps. Delirium requires finding and treating the precipitant (infection, urinary retention, pain, opioids and other drugs), with antipsychotics reserved for dangerous agitation. Formication with tremor, sweating, and tachycardia 1–3 days after the last drink is alcohol withdrawal and is treated with a benzodiazepine, since antipsychotics lower the seizure threshold. Olfactory hallucinations followed by automatisms call for EEG and MRI.