What to explain
Explain the change in thinking, mood, sleep, behavior, and ability to judge what is real.
My thinking changed. Can we identify the condition involved and check other causes? I brought a timeline of the other symptoms that started around the same time, my medicines, substance use, sleep notes, and examples from daily life.
Questions to take in
Questions about the diagnosis, physical health, medicines, and safety
- Which specific diagnosis or episode best explains the symptoms, and what evidence supports it?
- Could sleep loss, a medicine, withdrawal, alcohol, cannabis, stimulants, sedatives, or another substance be causing or worsening the change?
- Which medical causes need checking because of my age, sudden onset, physical symptoms, neurological signs, or medicine history?
- Do I need a physical examination, medication blood level, CBC, CMP, thyroid tests, vitamin tests, toxicology, brain imaging, EEG, or another test? What question would each answer?
- Would a structured psychiatric interview, trauma assessment, or neuropsychological evaluation change treatment or practical support?
- Which current medicine may affect alertness, memory, attention, coordination, blood pressure, sleep, weight, glucose, prolactin, kidneys, liver, thyroid, or heart rhythm?
- What is the plan for sleep, safety, daily care, therapy, medicine review, physical monitoring, and follow-up?
- What should I or my support person do if I stop sleeping, lose touch with reality, cannot care for myself, or become unsafe?
Mental health, medicine, sleep, and physical health checks
Use symptom questionnaires carefully and choose physical tests from the history.
PHQ-9 measures depression symptoms, GAD-7 measures common anxiety symptoms, PCL-5 measures PTSD symptoms, and medication review checks side effects and withdrawal. CBC, CMP, and thyroid tests look for selected physical causes. Cognitive testing measures specific thinking skills.
PHQ-9 Depression Questionnaire
Measures depression symptoms during the past two weeks and asks about thoughts of death or self-harm. The result needs clinical and safety assessment.
Read the test guideGAD-7 Anxiety Screener
Measures common anxiety symptoms during the past two weeks. It can't diagnose every anxiety condition or rule out medicine and medical causes.
Read the test guidePCL-5 PTSD Checklist
Measures PTSD symptoms after a traumatic event. A clinician still needs to assess the event, timing, impairment, other diagnoses, and immediate safety.
Read the test guideMedication Review
Reviews benefit, sedation, slowed thinking, restlessness, sleep, interactions, missed doses, withdrawal, and physical monitoring. Ask a clinician before stopping a medicine suddenly.
Read the test guideCBC + CMP Blood Test Bundle
Checks selected blood-cell, electrolyte, kidney, liver, and glucose problems. The symptoms and medicines decide which tests make sense.
Read the test guideThyroid Function Tests
Checks thyroid function when symptoms, history, examination, pregnancy, thyroid medicine, or an unusual episode raises concern.
Read the test guideNeuropsychological Evaluation
Measures attention, memory, language, thinking speed, and planning skills. It is useful when the result could guide care, rehabilitation, work, school, or disability support.
Read the test guideBefore the appointment
Bring the episode timeline, medicines, substances, sleep, safety problems, and exact daily changes.
A one-page timeline of changes in memory, concentration, speech, decisions, mood, fear, sleep, behavior, unwanted thoughts, detachment, voices, visions, or beliefs.
Bring seven days of sleep and activity notes. Include nights with very little sleep, daytime naps, unusually high energy, slowed behavior, agitation, or an inability to begin tasks.
Every prescription, over-the-counter medicine, supplement, recent dose change, missed dose, and medicine you stopped. Get the prescriber's OK before you stop a psychiatric medicine suddenly.
Honest dates and amounts for alcohol, cannabis, nicotine, caffeine, and other substances. Include stimulants, sedatives, psychedelics, and opioids. This information can change the diagnosis and medicine safety.
Bring two or three exact examples of what became difficult. This could be losing words, forgetting conversations, missing work, unsafe spending, not bathing, getting lost, or being unable to follow a simple task.
Earlier mental health diagnoses, hospital records, therapy notes, medication trials, brain scans, neurological tests, thyroid results, blood counts, and sleep studies.
Family history of bipolar disorder, psychosis, severe depression, OCD, suicide, seizures, dementia, or autoimmune disease if known.
A trusted person, if you agree, who has seen changes in sleep, speech, judgment, self-care, behavior, or ability to tell what is real.
The clinician needs to identify the specific condition, episode, medicine effect, substance effect, sleep problem, or medical cause. Sudden confusion, a first episode at an unusual age, seizure, fever, abnormal movement, or neurological change needs wider assessment.
How the doctor assesses this
Details that help identify a specific mental health condition
- Thinking changes again during a clear episode of a mental health condition. This may be depression, anxiety, trauma symptoms, mania, psychosis, OCD, or feeling detached from yourself or the world.
- The dates, sleep changes, behavior, family history, and effects on daily life fit the condition being considered.
- Symptoms improve when the underlying condition and sleep are treated without causing unacceptable medicine side effects.
Details that require medicine, substance, sleep, physical, or neurological causes to be checked
- There is no clear change in mood, fear, behavior, perception, sleep, unwanted thoughts, or ability to judge reality.
- The thinking problem follows standing, meals, exertion, infection, a medicine, substance use, or sleep apnea more closely than any mental health episode.
- A medical condition explains the symptoms better. Possibilities include fever, a seizure, unusual movement, a sudden nerve change, delirium, thyroid disease, anemia, or a vitamin shortage.
- The record says only ‘psychiatric’ without naming a condition, episode, medicine effect, or treatment question. Ask the clinician to be specific.
What to understand before choosing care
Questions that decide whether you need urgent care, specialist assessment, physical tests, neurological tests, therapy, or a medicine change.
- Which condition are you considering, and which of my symptoms point to it?
- Please separate changes caused by the illness from sleep loss, medicine side effects, missed doses, alcohol, cannabis, stimulants, sedatives, or another substance.
- Please check physical and neurological causes when the onset, age, examination, or other symptoms do not fit an established mental health condition.
- A questionnaire can measure symptoms but can't diagnose bipolar disorder, psychosis, OCD, PTSD, dissociation, or another condition by itself.
- Please make a safety plan if there are thoughts of harm or an inability to care for basic needs. A plan is also needed for dangerous decisions, loss of reality, or severe agitation.
What the research found
What current guidance says about diagnosis, physical health, medicines, and warning signs
Brain fog is not one psychiatric diagnosis. Depression, anxiety, PTSD, OCD, bipolar disorder, psychosis, dissociation, sleep loss, medicine effects, and substance use can affect thinking in different ways.
PHQ-9, GAD-7, and PCL-5 are symptom questionnaires. They can support assessment and follow-up but can't diagnose every condition or prove why concentration changed.
NICE advises against using a questionnaire in primary care to identify bipolar disorder. Diagnosis needs a detailed history. This covers mood, energy, sleep, behavior, distinct episodes, family history, medicines, substance use, physical health, and daily function.
A normal blood test or brain scan doesn't prove that symptoms are psychiatric or unreal. It only makes the condition measured by that test less likely at that time.
A psychiatric diagnosis does not remove the need to review physical health, sleep, medicines, substance use, and new neurological symptoms.
Autoimmune encephalitis, which is immune swelling in the brain, is uncommon. Urgent nerve assessment may be needed when memory or behavior changes fast. Seizures, unusual movements, loss of awareness, changed language, fever, or unstable heart rate and blood pressure make this more concerning.
How childhood, adolescence, older age, sex, pregnancy, and medicine safety change assessment.
Children and teenagers need assessment that includes development, school, family, sleep, bullying, substance exposure, safeguarding, and physical health. Adult questionnaires and medicine plans can't simply be copied to a child.
A first psychotic or manic episode often begins in adolescence or young adulthood, but symptoms at any age still need a full assessment.
A first major change in an older adult needs careful medical review. The doctor may need to check for sudden confusion, infection, medicine effects, pain, or sight or hearing loss. Stroke, seizures, thyroid disease, vitamin deficiency, sleep apnea, and a disease that slowly harms the brain may also need checking.
Pregnancy, postpartum, menstrual changes, and menopause can affect symptoms and medicine safety in women. Before medicine decisions, say if you're pregnant or planning a pregnancy.
Age and sex can change medicine effects, dosing, pregnancy risk, heart rhythm, metabolic risk, and the likely medical causes. They do not confirm a psychiatric diagnosis.
If the answer is no
If your doctor will not order a mental-health blood test or brain scan
A blood test or brain scan can't diagnose most mental health conditions. The first step is a set of questions about your symptoms and how they affect your life. Blood tests, a nerve exam, or brain imaging may be useful when your history suggests a physical cause.
What changes the answer
- Bring a short symptom timeline. Note changes in mood, sleep, energy, thoughts, behavior, and daily life. Include when they began and whether they come in episodes.
- Ask for the right screening questions. Different questionnaires look for depression, anxiety, substance use, or other concerns. A screen can show what needs a fuller assessment.
- Name signs of a possible physical cause. A new medicine, substance use, thyroid symptoms, an infection, or a change in movement, speech, strength, or sensation can support focused medical tests.
- Ask for a formal assessment. If medical tests aren't needed, ask who will assess the symptoms and when the findings will be reviewed.
United States, United Kingdom, and Australia
Mental health and medical assessment.
US United States
Bring the full timeline, not only a brain fog label. Ask for a specific mental health assessment, physical and neurological review, medicine and substance review, safety plan, and tests chosen for the symptoms.
- Early signs of psychosis can include unclear thinking, poor sleep, confused speech, and pulling away from people. A person may also have trouble telling what is real.
- A mental health assessment should include physical health, medicines, substance use, family history, symptoms over time, and daily function.
- Use emergency services or the nearest emergency department when there is immediate danger or severe loss of reality.
UK United Kingdom
Ask the GP to identify the specific problem. Bring the timeline and medicines. Ask for physical health review, substance and sleep assessment, appropriate blood tests, safety planning, and referral when symptoms are severe or unclear.
- NICE says suspected mania, severe depression, or danger to self or others needs urgent specialist assessment.
- A bipolar assessment looks for clear episodes and changes in behavior. It also covers family history, physical health, medicines, side effects, substance use, and daily function.
- Questionnaires should not be used alone in primary care to identify bipolar disorder.
AU Australia
Bring symptoms, medicines, substances, and safety concerns. Ask which diagnosis best fits and what the physical and nerve examinations found. Review medicines and substance use, agree on a safety plan, and ask which referral fits the level of need.
- A mental illness, drug use, medicine, or a physical or neurological condition can cause psychosis.
- Early assessment helps identify the cause and reduce harm.
- Emergency departments and local mental health crisis teams can assess urgent symptoms.
Safety
Check basic needs, sleep, safety, work, school, money, driving, and care of dependents.
- Record sleep, energy, mood, fear, unusual experiences, medicine timing, substances, and one daily task. Stop recording and seek help if safety is worsening.
- Check whether you can eat, bathe, manage money, take medicines, work, drive and care for dependants.
- Use one trusted person to help notice missed sleep, fast or confused speech, withdrawal, risky behavior, poor self-care, or loss of reality.
- Do not drive, operate dangerous equipment, sign major contracts, or make large financial decisions when judgment, alertness, reality testing, or coordination is impaired.
Source checked
Sources behind this handout.
- 01
NIMH, Bipolar Disorder
Source - 02
NIMH, Understanding Psychosis
Source - 03
American Psychiatric Association, Psychiatric Medications
Source - 04
American Psychiatric Association, What Is Mental Illness?
Source - 05
NICE CG185, Bipolar Disorder Recommendations, updated 2025
Source - 06
NICE CG178, Psychosis and Schizophrenia in Adults
Source - 07
NICE CG31, Obsessive-compulsive Disorder
Source - 08
Healthdirect Australia, Psychosis
Source - 09
Graus et al., Clinical Approach to Autoimmune Encephalitis (2016)
Source