The Complete MSE Guide for CASC: What Examiners Really Look For

The Mental State Examination (MSE) is the psychiatric equivalent of the physical examination. In the CASC, your ability to observe, interpret, and document mental state findings is assessed both explicitly and implicitly. Unlike physical examination, the MSE begins the moment you see the patient and continues throughout the entire consultation.

MSE in the CASC Context

While some stations explicitly ask you to perform an MSE, you should be conducting a mental state examination in EVERY station. Examiners observe whether you:

• Notice and document relevant mental state findings
• Use appropriate psychiatric terminology with precision
• Integrate MSE findings into your clinical formulation
• Can differentiate between normal and abnormal findings
• Recognise pathological signs that the simulated patient is portraying
• Use the MSE to support or refine your diagnostic impression

A key point that many candidates miss: in CASC stations where you are performing a history, the examiner is still assessing whether you notice and comment on relevant MSE findings. If the simulated patient is displaying psychomotor retardation, thought disorder, or poor eye contact, the examiner expects you to register this — even if the station does not explicitly ask for an MSE.

The Components

1. Appearance and Behaviour

This is what you observe before the patient says a word. Important areas:

• General appearance: Age (do they look their stated age?), build (BMI observation is relevant in eating disorders, neglect), cleanliness, grooming, state of clothing
• Self-care indicators: Unkempt appearance, body odour, stained clothing may suggest self-neglect (depression, psychosis, substance misuse, dementia)
• Psychomotor retardation: Slowed movements, delayed initiation of actions, poverty of movement (depression, catatonia, parkinsonism)
• Psychomotor agitation: Restlessness, fidgeting, hand-wringing, pacing, inability to sit still (anxiety, agitated depression, akathisia)
• Eye contact: Normal, reduced (depression, anxiety, autism), intense/staring (mania, paranoia), avoidant (social anxiety, shame)
• Rapport: Easy to establish, difficult, guarded, hostile, overfamiliar
• Unusual movements: Tremor (medication side effects, anxiety, alcohol withdrawal), tardive dyskinesia (antipsychotic use), tics, stereotypies, mannerisms, waxy flexibility (catatonia), choreiform movements
• Posture and gait: Stooped (depression), rigid (parkinsonism, catatonia), restless shifting

Examiner tip Do not simply write "appropriate appearance" — this tells the examiner nothing. Be specific: "The patient appeared well-groomed and dressed appropriately for the weather, consistent with adequate self-care."

2. Speech

Speech abnormalities can be highly diagnostic. Assess systematically:

• Rate: Normal, increased (pressure of speech in mania, anxiety), decreased (depression, sedation)
• Volume: Normal, loud (mania, hearing impairment), quiet/whispered (depression, anxiety, paranoia)
• Tone: Normal variation, monotonous (depression, negative symptoms of schizophrenia), heightened/excitable (mania)
• Rhythm: Normal, dysarthric (substance intoxication, neurological), stuttering
• Spontaneity and productivity: Spontaneous and productive (normal), reduced spontaneity with long pauses (depression), over-inclusive and hard to interrupt (mania)
• Latency of response: Normal, increased (depression, thought disorder, learning disability — allow time before assuming abnormality)
• Form abnormalities observed in speech: Circumstantial (eventual return to point), tangential (never returns to point), derailment/loosening of associations, word salad, neologisms, clang associations, flight of ideas (topic changes linked by sound or superficial association, seen in mania), perseveration (repetitive return to same topic), echolalia

Key distinction **Pressure of speech** (increased rate, volume, difficult to interrupt) points toward mania. **Poverty of speech** (reduced quantity and spontaneity) is seen in depression and negative symptoms of schizophrenia.

3. Mood and Affect

This is one of the most commonly confused areas. Getting the distinction right signals clinical competence:

• Mood (subjective — what the patient tells you): Always use the patient's own words in quotes. Ask: "How would you describe your mood?" / "How have you been feeling in yourself?" Example documentation: Mood described as "terrible, I feel like I'm at the bottom of a well"
• Affect (objective — what you observe): Describe using standard descriptors
• Affect — Range: Full range, restricted (limited emotional expression), blunted (markedly reduced), flat (absent — no emotional expression at all)
• Affect — Reactivity: Reactive (changes appropriately during conversation), non-reactive/fixed (does not change regardless of topic)
• Affect — Congruence: Congruent (affect matches stated mood and conversation content), incongruent (affect is inappropriate to content — e.g., laughing while describing bereavements, seen in schizophrenia)
• Affect — Stability: Stable, labile (rapid, unpredictable shifts — seen in organic conditions, emotionally unstable personality disorder, pseudobulbar affect)
• Affect — Quality: Anxious, irritable, euphoric, dysphoric, suspicious, perplexed

4. Thought

Thought assessment has three components — form, content, and possession:

Thought form (how the patient thinks — assessed through their speech): - Normal/linear: Goal-directed, logical progression of ideas - Circumstantial: Over-inclusive but eventually reaches the point — often seen in anxiety, obsessional personality - Tangential: Diverges from the topic and never returns to the original point - Flight of ideas: Rapid shift between topics with identifiable links (phonetic, semantic, or visual) — characteristic of mania - Loosening of associations: No identifiable link between ideas — characteristic of schizophrenia - Knight's move thinking: Abrupt, illogical jumps between unrelated topics — severe form of loosening of associations - Thought blocking: Sudden interruption of the train of thought, followed by a new unrelated thought — the patient often notices and comments on it (vs. normal losing one's train of thought) - Perseveration: Inappropriate repetition of the same response or theme - Neologisms: Made-up words with idiosyncratic meaning to the patient

Thought content (what the patient thinks about): - Delusions: Fixed, false beliefs not amenable to reason, out of keeping with cultural background. Classify by type: persecutory (most common), grandiose, referential (events/media refer specifically to them), nihilistic (Cotard's — belief that they or body parts are dead/don't exist), erotomanic, somatic, jealous. Assess: onset, development, degree of conviction, impact on behaviour, distress caused - Overvalued ideas: Strongly held beliefs that are comprehensible given the patient's background but are pursued beyond reason (vs. delusions which are entirely false) - Obsessions: Intrusive, unwanted, repetitive thoughts that are ego-dystonic (the patient recognises them as their own and distressing). Distinguish from ruminations (ego-syntonic worrying) and delusions (held with conviction) - Preoccupations: Dominant themes of thought — illness, guilt, finances, relationships - Suicidal ideation: Passive thoughts of death, active suicidal ideation, planning (covered in detail in risk assessment) - Homicidal ideation: Thoughts of harming others

Thought possession (first-rank symptoms — Schneider): - Thought insertion: Belief that thoughts are being put into the mind by an external agency - Thought withdrawal: Belief that thoughts are being removed from the mind - Thought broadcasting: Belief that thoughts are accessible to others (can be heard, read, transmitted)

5. Perception

Perceptual disturbances are diagnostically important:

• Hallucinations (perception without stimulus — detailed by modality below)
• Auditory hallucinations: Most common in psychiatric illness. Second person (talking to patient — depression, PTSD) vs. third person (talking about patient — schizophrenia). Running commentary. Command hallucinations (especially important for risk — do they obey?). Explore: content, number of voices, frequency, duration, volume, where they seem to come from, patient's explanation
• Visual hallucinations: More common in organic pathology (delirium, substance intoxication/withdrawal, dementia with Lewy bodies, occipital lobe pathology). Also seen in Charles Bonnet syndrome (visual impairment). Explore: formed vs. unformed, content, associated features
• Tactile hallucinations: Formication (sensation of insects crawling under skin — stimulant misuse, alcohol withdrawal, delirium). Somatic passivity
• Olfactory and gustatory hallucinations: Rare, consider temporal lobe pathology, psychotic depression (smell of rotting)
• Illusions: Misperceptions of real stimuli — common in delirium, can be normal (especially in conditions of low sensory input)
• Depersonalisation: Feeling detached from oneself, as if watching from outside — seen in anxiety, depression, PTSD, dissociative disorders
• Derealisation: Feeling that the surroundings are unreal — similar associations to depersonalisation
• Pseudohallucinations: Experienced as arising from within the mind rather than external space, typically with preserved insight — distinction from true hallucinations is important but debated

How to ask about hallucinations - "Have you had any unusual experiences recently?" (open screen) - "Have you heard sounds or voices when there doesn't seem to be anyone around?" (auditory) - "Have you seen things that other people might not have been able to see?" (visual) - "Have you noticed any unusual sensations in your body?" (tactile/somatic) - If positive: "What do the voices say?" / "How often does this happen?" / "Do the voices ever tell you to do things?" (command hallucinations — critical for risk)

6. Cognition

Cognitive assessment is important in older adult stations, delirium, and suspected organic presentations:

• Orientation: To time (day, date, month, year, season), place (building, town, county, country), person (name, age, date of birth)
• Attention and concentration: Serial 7s (subtract 7 from 100 serially), spell WORLD backwards, months of the year backwards
• Registration and short-term memory: Give 3 words (e.g., apple, table, penny), ask for immediate recall, then recall after 5 minutes
• Long-term memory: Recent events (what did they have for breakfast, news events), remote events (personal history, historical dates)
• Formal screening tools: MMSE (Mini-Mental State Examination — out of 30, <24 suggests cognitive impairment), ACE-III (Addenbrooke's Cognitive Examination — more sensitive, out of 100), MoCA (Montreal Cognitive Assessment — good at detecting MCI)
• Executive function: Verbal fluency (name as many animals as possible in 1 minute — <15 is abnormal), clock drawing test, Luria sequences, abstraction (proverb interpretation, similarities)
• Frontal lobe signs: Disinhibition, perseveration, utilisation behaviour, grasp reflex, motor sequencing difficulties

When to perform formal cognitive testing In CASC, perform formal cognitive screening when the station involves suspected dementia, delirium, head injury, or when the patient's cognitive function appears impaired during your assessment. Don't attempt a full ACE-III in a 7-minute station — select the most relevant domains to test.

7. Insight and Judgement

Insight is frequently missed by candidates but is specifically assessed by examiners:

• Awareness of illness: Does the patient recognise that they are unwell? "Do you think there might be a problem with your mental health?"
• Understanding of the nature of illness: Can they identify what is wrong? Do they attribute symptoms to a psychiatric condition or to external causes?
• Understanding of need for treatment: Do they accept that treatment is needed? Are they willing to engage with the proposed management plan?
• Capacity to make treatment decisions: Related to but distinct from formal capacity assessment

Grading insight (David's model — useful framework for documentation): - Full insight: Recognises illness, attributes symptoms correctly, accepts treatment - Partial insight: Acknowledges some symptoms but attributes them incorrectly, or recognises illness but refuses treatment - No insight: Denies illness entirely, attributes symptoms to external causes, refuses all intervention

Judgement: The ability to make reasonable decisions. Assess through the patient's responses to clinical scenarios and their decisions about their own care. Poor judgement may reflect cognitive impairment, impaired insight, or manic states.

MSE Findings Across Key Disorders

Understanding the typical MSE pattern for major conditions helps you integrate MSE findings into your diagnostic formulation:

Severe Depression Appearance: Self-neglect, weight loss, tearful. Psychomotor retardation or agitation. Speech: Reduced rate, volume, spontaneity, increased latency. Mood: "Low"/"awful"/"empty". Affect: Restricted range, reactive to negative themes but not positive. Thought: Guilt, worthlessness, hopelessness, nihilistic delusions in psychotic depression, suicidal ideation. Perception: Second-person auditory hallucinations (derogatory) in psychotic depression. Cognition: Pseudo-dementia pattern possible — poor concentration and memory secondary to depression. Insight: Often partially preserved but may be distorted by hopelessness.

Mania Appearance: Bright clothing, excessive make-up/jewellery, signs of disinhibition. Increased psychomotor activity. Speech: Pressure of speech — rapid, loud, difficult to interrupt. Mood: "Fantastic"/"on top of the world" (or irritable). Affect: Euphoric or irritable, labile, incongruent to situation. Thought: Flight of ideas, grandiose delusions, increased goal-directed ideas, reduced risk awareness. Perception: Hallucinations possible in severe mania (congruent with grandiosity). Cognition: Distractible, may appear to have poor concentration but underlying cognitive function intact. Insight: Typically poor — "I've never felt better."

Schizophrenia (Acute Episode) Appearance: May show self-neglect, perplexed or suspicious expression, guarded behaviour. Speech: May be normal or show formal thought disorder (tangential, loosening of associations, neologisms). Mood: Variable — may report anxiety, low mood, or perplexity. Affect: Often incongruent, blunted or flat (negative symptoms), may be perplexed or suspicious. Thought: Delusions (often persecutory or referential), thought disorder, possible first-rank symptoms. Perception: Auditory hallucinations (third person, running commentary, command hallucinations). Cognition: May be impaired by distraction or thought disorder, but formal cognitive function often preserved. Insight: Typically poor.

Delirium Appearance: Unwell, may have medical paraphernalia, fluctuating alertness. Speech: May be incoherent, confabulating. Mood: Often distressed, frightened, perplexed. Affect: Labile, often anxious. Thought: Disorganised, fleeting persecutory ideas (not systematised delusions). Perception: Visual hallucinations (characteristically), illusions, misidentification. Cognition: Markedly impaired — disoriented (especially to time), inattentive, global cognitive impairment, distractible. Insight: Impaired.

Dementia (Early-Moderate) Appearance: May be well-groomed (maintained social facade) or show signs of self-neglect depending on stage. Speech: Word-finding difficulties, reduced fluency, circumlocutory. Mood: Variable — may be unaware or frustrated. Affect: May be labile or apathetic. Thought: Impoverished content, possible confabulation. Perception: Usually normal in early stages (visual hallucinations suggest Lewy Body dementia). Cognition: Progressive impairment — memory (typically short-term first), orientation, executive function, visuospatial. Insight: Often limited — may minimise difficulties or be unaware.

Presenting Your MSE Findings

If asked to present your MSE to an examiner, follow the standard order and use precise terminology:

"On mental state examination, Mr/Mrs X appeared [appearance]. Psychomotor activity was [normal/retarded/agitated]. Eye contact was [description] and rapport was [easy to establish/difficult/guarded]. Speech was [rate, volume, tone, form]. Mood was described as [patient's own words in quotes]. Affect was [range, reactivity, congruence]. Thought form was [linear/circumstantial/etc.]. Thought content revealed [delusions/preoccupations/obsessions] with [no/passive/active] suicidal ideation. There were [no perceptual disturbances/describe hallucinations]. Cognition was [intact/impaired — specify domains]. Insight was [full/partial/absent]."

Keep it structured, concise, and evidence-based. Don't speculate — report what you observed and assessed.

Example MSE Write-Up

"On mental state examination, Mrs Jones is a 45-year-old woman who appeared older than her stated age. She was casually dressed with evidence of reduced self-care — her clothing was stained and her hair unwashed. Psychomotor retardation was evident with slow initiation of movement and reduced gesturing. Eye contact was reduced and rapport was established with effort. Speech was slow in rate, reduced in volume, with increased latency of response. She described her mood as 'empty, like nothing matters anymore.' Her affect was restricted in range, non-reactive to positive topics but tearful when discussing her children, and congruent with her stated mood. Thought form was linear but with poverty of content. Thought content was dominated by themes of guilt and worthlessness. She described passive suicidal ideation — 'I've thought it would be easier if I wasn't here' — but denied active planning, intent, or access to means. No obsessions or delusions were elicited. She denied perceptual disturbances, and there was no evidence of hallucinations during the consultation. Cognitive screening was not formally conducted but she was oriented in time, place, and person, and her attention appeared adequate. Insight was partial — she acknowledged feeling unwell but was ambivalent about the need for psychiatric treatment."

Common Mistakes to Avoid

1. Confusing mood and affect — Mood is subjective (patient's words), affect is objective (your observation). Getting this wrong signals poor clinical knowledge.
2. Writing "appropriate" or "normal" without specifics — Always document what you actually observed; vague descriptors do not demonstrate competence.
3. Missing insight assessment — This is specifically marked by examiners and frequently omitted by candidates.
4. Not testing cognition when indicated — If the station involves an older adult, delirium, or head injury, some cognitive assessment is expected.
5. Confusing thought form and thought content — Form is how they think (process); content is what they think about (themes, beliefs).
6. Forgetting to assess for first-rank symptoms in psychosis — Thought insertion, withdrawal, broadcasting, and passivity phenomena should be screened for.
7. Not commenting on the MSE during history stations — Even in stations focused on history taking, noting relevant MSE findings (psychomotor changes, speech abnormalities, affect) demonstrates thorough clinical observation.
8. Using "hallucination" and "illusion" interchangeably — These are distinct phenomena; precise terminology matters.

Practice Checklist

• [ ] Can I present a full MSE in a structured, concise format under 2 minutes?
• [ ] Do I know the difference between mood and affect, and can I describe affect using range, reactivity, and congruence?
• [ ] Can I distinguish between different types of thought form disorder (circumstantial, tangential, flight of ideas, loosening of associations)?
• [ ] Do I routinely assess insight across the three domains (awareness of illness, understanding of nature, acceptance of treatment)?
• [ ] Can I describe the typical MSE findings in depression, mania, schizophrenia, delirium, and dementia?
• [ ] Do I know how to ask about hallucinations across all modalities?
• [ ] Can I identify first-rank symptoms and explain their significance?
• [ ] Have I practiced integrating MSE findings into a diagnostic formulation?
• [ ] Do I notice and comment on MSE findings even in history-focused stations?