6.1.10 Other psychiatric disorders

Other psychiatric disorders presenting in adulthood

Prevalence and mixed presentations

The historical US Epidemiologic Catchment Area survey used DSM-III (Diagnostic and Statistical Manual, third edition). Its lifetime prevalence estimates describe those study definitions, not current ICD-11 diagnostic requirements.

• Mixed depressive and anxiety disorder in the International Classification of Diseases, 11th revision (ICD-11), is concurrent depressive and anxiety symptoms, each too sparse or mild for its own diagnosis, with no history of hypomania.

• It lasts under two years, which keeps it short of dysthymia.

Acute and other primary psychotic disorders

Acute and transient psychotic disorder

• Acute and transient psychotic disorder (ICD-11) is an abrupt, polymorphic psychosis in a previously well adult, often linked to a stressor, that remits fully within weeks.

• Negative symptoms are absent.

• The oneiroid state is a dream-like, scenic alteration of consciousness seen in some acute psychoses, with vivid fantastical scenes in which imagination and reality blur.

Schizoaffective and delusional disorder

• Schizoaffective disorder (ICD-11) needs the full schizophrenia criteria and a moderate or severe mood episode together, starting within days of each other, for at least a month.

• Delusional disorder (ICD-11) is a delusion or related set of delusions typically lasting at least three months, with an otherwise intact mental state and intact functioning.

• Delusional disorder lacks clear persistent hallucinations and other characteristic schizophrenia symptoms; limited hallucinations linked to the delusional theme may occur.

• ICD-11 has no separate category for folie à deux (induced delusional disorder) and describes it within delusional disorder.

Named syndromes

Catatonia

Catatonia is a psychomotor syndrome with psychiatric, medical and drug causes, and mood disorders are common psychiatric causes.

• ICD-11 has separate catatonia categories for association with a mental disorder, induction by a substance or medication, and secondary medical causes.

• Diagnosis needs several characteristic signs, generally at least three.

• Medical causes to exclude are autoimmune encephalitis, seizures, infection, metabolic or endocrine disease, and withdrawal from benzodiazepines or clozapine.

Signs

• Ambitendency is a recognised catatonic sign, whereas ambivalence is not.

• Catatonic resistance rises in step with the force applied, whereas Parkinsonian rigidity is fixed and uniform, activated by moving the opposite limb, and cogwheeling with tremor.

• The Bush-Francis scale structures assessment and tracks response, but it does not replace a search for the cause.

Malignant catatonia

• Malignant catatonia is catatonic signs followed days later by fever and autonomic instability, sometimes with rigidity and raised creatine kinase, and it is an emergency.

• Stimulant use in untreated psychosis can precipitate it.

• It is told from neuroleptic malignant syndrome by the lack of exposure to a dopamine-blocking drug.

• Physical care prevents dehydration, malnutrition, thrombosis, pressure injury, aspiration, rhabdomyolysis and contractures, and checks refeeding risk when feeding resumes.

Treatment

• A benzodiazepine, usually lorazepam, is first-line for catatonia, whether stuporous or alternating excitement and stupor, once a medical cause is excluded, with the dose raised under monitoring.

• Electroconvulsive therapy (ECT) is held for benzodiazepine failure or malignant catatonia, and in malignant catatonia it should not be delayed.

• In schizophrenia, ECT is the treatment once catatonia becomes physically dangerous, such as refusal of food and fluid.

• Catatonia in schizophrenia responds less well to benzodiazepines and ECT, and has a poorer outcome, than catatonia in a mood disorder.

• Antipsychotics can worsen catatonia or precipitate neuroleptic malignant syndrome.

• The underlying cause is treated at the same time, because catatonia may recur with it.

Stress-related disorders

ICD-11 separates disorders linked to an identifiable stressor from anxiety disorders, which need none.

Acute stress reaction and adjustment disorder

• An acute stress reaction is post-traumatic stress disorder (PTSD)-type symptoms, or transient confusion, withdrawal or autonomic arousal, starting within hours of an extreme event and fading within about a week.

• ICD-11 classifies acute stress reaction outside the mental disorders, so support should avoid medicalising it.

• Symptoms usually begin to ease within about 48 hours of the event or of removal from the threat.

• ICD-11 advises considering other diagnoses when there is no easing within one week of the stressor ending.

• PTSD requires its characteristic clusters for at least several weeks in ICD-11, with significant impairment; persistence alone is insufficient.

• Adjustment disorder is preoccupation with an identifiable stressor and failure to adapt, with significant impairment; in ICD-11 it usually starts within a month and resolves within six months of the stressor ending.

• Adjustment disorder still needs a self-harm and suicide risk assessment.

• Combat stress reaction is a state of hyperarousal with irritability as a core feature, along with broken sleep and guilt.

PTSD and complex PTSD

ICD-11 PTSD follows an extremely threatening or horrific event and needs three core clusters.

• Complex PTSD (ICD-11) is PTSD plus three disturbances of self-organisation: affect dysregulation, negative self-concept and relationship difficulties.

• Complex PTSD still needs the core PTSD clusters, and it often follows repeated or inescapable trauma.

• In complex PTSD the self-image is persistently negative, whereas in borderline personality disorder it shifts, although the two overlap.

• The conditional risk of PTSD depends on the event: natural disasters carry among the lowest risks, and intentional interpersonal violence, especially sexual and intimate violence, the highest.

• Genuine PTSD nightmares vary in detail while staying tied to the trauma, so a fixed, identical nightmare replayed every night points to malingering.

• Depression, substance use and other anxiety disorders commonly coexist.

Management under National Institute for Health and Care Excellence (NICE) guideline NG116

• Venlafaxine is the one non-SSRI antidepressant NICE names for PTSD in adults.

• Psychologically focused debriefing and relaxation have no supporting evidence.

Factitious disorder and malingering

Both involve deliberate deception, and the motive separates them.

• Factitious disorder imposed on self is deliberate feigning, falsifying or inducing of signs or symptoms with no external reward beyond the patient role.

• Methods include tampering with specimens, falsifying records and self-induced skin lesions that are concealed and denied.

• The person conceals their history and obstructs access to previous care and medical records.

• Malingering is deliberate fabrication or exaggeration of symptoms for an identifiable external incentive, such as avoiding work, escaping a legal process, or obtaining shelter or money.

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS)

Diagnosis

• Fatigue is the single defining symptom: severe, disabling and not relieved by rest.

• Pain, headache, lymph node symptoms and mood symptoms are associated features only.

• The positive profile is debilitating fatigue with delayed and prolonged post-exertional malaise, unrefreshing sleep and cognitive difficulty, persisting for months without another explanation.

• Enjoyment is preserved, and there is no excessive worry or preoccupation with symptoms.

• In an adult, ME/CFS is suspected once symptoms have lasted six weeks and diagnosed when they have persisted for three months.

• There is no confirmatory test; the diagnosis is clinical, from the pattern and duration, and tests only exclude other causes.

• Joint pain occurs without swelling or redness, so significant weight loss or visibly swollen, red joints point to another diagnosis.

Course and management

• Treating comorbid depression helps even when patients resist a psychiatric label.

• Better prognosis goes with not attributing the illness to a physical cause, a sense of control, staying active, lower initial severity and younger age, and their opposites predict a worse outcome.

• Perpetuating factors, such as habitual avoidance of physical and mental exertion, act after onset to keep the illness going.

• Perpetuating factors are told from predisposing factors, which create vulnerability before onset, and precipitating factors, which trigger it.

Attention deficit hyperactivity disorder (ADHD) in adults

• Adults present with disorganisation, missed deadlines, unfinished tasks, restlessness and impulsive decisions, often more obviously when external structure falls away.

• Emotional dysregulation is common but is not a core criterion.

• About 5% of children meet criteria, 40 to 50% keep the full syndrome as adults, and adult prevalence is roughly 3 to 4%.

• ADHD is male-predominant, about 2:1 in children and narrower in adults, and it is under-recognised in females.

Diagnosis

• ICD-11 distinguishes predominantly inattentive, predominantly hyperactive-impulsive and combined presentations according to the current symptom pattern.

• Collateral history and school reports support diagnosis, and rating scales cannot diagnose alone.

• ADHD runs persistently from childhood, whereas bipolar symptoms cluster into episodes.

• Before medication, check cardiovascular history, examination and family history, including sudden cardiac death before 40.

Management under NICE NG87

• Atomoxetine is the non-stimulant licensed for adults and the preferred switch when a stimulant provokes tics.

• Guanfacine is licensed for children and adolescents only, so adult use needs tertiary advice, and clonidine is off-label.

• Lisdexamfetamine holds a UK licence for adults with ADHD.

• Lisdexamfetamine is a prodrug whose release cannot be sped up by crushing, snorting or injecting, so it has the lowest misuse potential and suits an adult with misuse or diversion risk.

• Treatment is reviewed at least annually, and transition from child services needs clear responsibility for prescribing and monitoring.

Insomnia

• Insomnia is difficulty sleeping despite adequate opportunity, with daytime impairment.

• Chronic insomnia lasts at least three months and recurs each week, and restricted opportunity alone is insufficient sleep, not insomnia.

Psychological treatment

• Cognitive behavioural therapy for insomnia (CBT-I) is first-line for insomnia lasting three months or more, ahead of any hypnotic.

• Stimulus control re-establishes the bed as a cue for sleep rather than wakeful arousal, for example by getting up if not asleep within about 20 minutes.

• Sleep restriction matches time in bed to actual sleep before increasing it, adapted where extra sleepiness creates risk.

• Sleep hygiene alone is usually insufficient, and its core rule is a regular wake time, because a fixed rising time entrains the circadian rhythm.

Hypnotics

• NICE recommends a short-acting Z-drug such as zolpidem, at the lowest dose for the shortest time, for short-term insomnia.

• Tolerance to the sleep-inducing effect of benzodiazepines develops within days of nightly use, which is why courses are short.

• If one Z-drug or short-acting benzodiazepine fails, the hypnotic is stopped and no other is given.

• A pre-existing anxiety disorder increases the risk of benzodiazepine dependence.

NICE technology appraisal 922 allows daridorexant for chronic insomnia on at least three nights a week with considerable daytime impairment, after CBT-I has failed or is unsuitable or unavailable, with review within three months.

Narcolepsy and other hypersomnias

Narcolepsy

• The narcolepsy tetrad is excessive daytime sleepiness, cataplexy, hypnagogic hallucinations and sleep paralysis, and sleep attacks are refreshing.

• Narcolepsy type 1 is caused by loss of hypocretin (orexin) neurons in the lateral hypothalamus, giving low cerebrospinal fluid hypocretin-1.

• Cataplexy is emotion-triggered loss of muscle tone with retained consciousness, from rapid eye movement (REM) atonia intruding into wakefulness.

• Not all narcolepsy involves cataplexy or proven orexin deficiency.

• Cataplexy is not catalepsy, the waxy flexibility of catatonia.

• Sleep-related hallucinations are not psychosis, and cataplexy is not feigned collapse.

• Modafinil promotes wakefulness by weak dopamine transporter blockade, with downstream activation of hypothalamic histamine and orexin neurons, unlike classical amfetamine-like stimulants.

• Headache is the most frequent adverse effect of modafinil and is dose-related.

Kleine-Levin syndrome

• Kleine-Levin syndrome is recurrent episodes of prolonged sleep lasting days to weeks, with overeating, sexual disinhibition and dreamlike unreality, and normal function in between.

• It usually starts in adolescent boys, often after an infection, and becomes milder and rarer with age.

Sleep apnoea

• In obstructive apnoea, snoring is highly sensitive but nonspecific, while nocturnal choking or gasping is specific but insensitive.

• Fatigue, poor concentration, memory complaints and low mood from obstructive apnoea can resemble resistant depression.

• Psychotropic weight gain and sedation can worsen breathing or arousal.

• The Epworth Sleepiness Scale supports assessment, but referral is not based on it alone.

• Moderate or severe disease is treated with continuous positive airway pressure and lifestyle measures.

Parasomnias

The International Classification of Sleep Disorders, third edition (ICSD-3), sorts parasomnias into three groups.

• Non-REM-related parasomnias are the disorders of arousal (confusional arousals, sleepwalking, sleep terrors) plus sleep-related eating disorder.

• The other two groups are REM-related and other parasomnias.

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• REM sleep behaviour disorder arises from damage to the brainstem circuitry for REM atonia, the dorsal pontine tegmentum and its medullary relay.

• Onset after 50 with anosmia often heralds Parkinson's disease or dementia with Lewy bodies.

Restless legs syndrome and periodic limb movements

Restless legs syndrome needs all five of these criteria.

1. The person has an urge to move the legs.

2. The urge is worse at rest.

3. It is relieved by getting up and moving.

4. It is worse in the evening or at night.

5. Mimics have been excluded.

• Supportive features are periodic limb movements, response to dopaminergic treatment, a first-degree relative with the syndrome and lack of profound daytime sleepiness.

• Restless legs syndrome is a leg-confined urge at rest in the evening, relieved by walking, whereas akathisia is daytime whole-body inner restlessness.

• Poor or disrupted sleep aggravates it.

• Iron deficiency, shown by serum ferritin below 75 micrograms/L, is the established metabolic association and correctable cause, through iron's role in dopamine synthesis.

• Serotonergic antidepressants, antipsychotics, dopamine-blocking antiemetics and sedating antihistamines aggravate it.

• Periodic limb movements in sleep are involuntary, repetitive, stereotyped leg jerks, often noticed by a bed partner.

• Polysomnography finds them in around 80% of people with restless legs syndrome.

• Periodic limb movement disorder (formerly nocturnal myoclonus) is a diagnosis of exclusion made on polysomnography when the movements disturb sleep or daytime function.

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Premenstrual dysphoric disorder (PMDD)

Cause and diagnosis

• Circulating oestradiol and progesterone are normal, and symptoms come from an abnormal central response to their normal cyclical change.

• Symptoms recur when physiological hormone levels are added back.

• PMDD is severe, mainly affective symptoms confined to the late luteal phase that lift after menses, followed by a symptom-free week, with impairment.

• At least one mood symptom (lability, irritability, low mood or anxiety) is required, so physical symptoms alone never make the diagnosis.

• Criteria also include somatic symptoms (breast tenderness or swelling, joint or muscle pain, bloating, weight gain) and hypersomnia or insomnia, all confined to the late luteal phase.

• Prospective daily symptom ratings across at least two symptomatic cycles confirm the diagnosis, and history alone gives only a provisional one.

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Treatment

• SSRIs such as sertraline are the first-line, best-evidenced drugs, ahead of hormonal, herbal, anxiolytic or lifestyle measures.

• Fluoxetine has the most extensive randomised trial evidence among SSRIs for severe premenstrual syndrome and PMDD.

• The effect is serotonergic, so an antidepressant acting on noradrenaline or dopamine without serotonin reuptake inhibition lacks evidence.

• SSRIs act within days in PMDD, so luteal-phase dosing (ovulation to menses) works, as does continuous dosing.

• Luteal-phase dosing is well tolerated with no significant discontinuation syndrome, but it may relieve physical symptoms less than continuous dosing.

• Drospirenone, which blocks mineralocorticoid and androgen receptors, is the progestogen of choice in a combined oral contraceptive for PMDD.

Other drug treatments

• Lithium has a reported role in steroid-induced mood disturbance, although reducing the steroid and giving an antipsychotic come first.

• Fluoxetine is the drug NICE names for adult body dysmorphic disorder once a psychological approach has not worked, including when conviction is delusional.

Organic psychoses and secondary psychotic disorders

Terminology

• Organic psychosis is an older term for psychosis with an identifiable medical cause; ICD-11 calls it secondary psychotic syndrome.

• ICD-11 classifies delirium, dementia and substance- or medication-induced disorders separately, so infection with acute inattention is classed as delirium.

Clues to a secondary cause

• Primary psychosis can still begin after 60, and a person with schizophrenia can develop delirium or toxicity, so new deterioration is not assumed to be relapse.

Prescribed drugs

Heavy metal poisoning

Vitamin B12 deficiency

• Vitamin B12 deficiency is a reversible cause of neuropsychiatric illness whose features can occur without anaemia or macrocytosis, so a normal blood count does not exclude it.

• It causes subacute combined degeneration of the cord and megaloblastic anaemia, which commonly occur together.

• Its assessment depends on where B12 is absorbed, how long body stores last and the limits of serum B12 testing.

Thiamine deficiency

• Wernicke's encephalopathy is acute thiamine deficiency with the triad of confusion, gait ataxia and ophthalmoplegia, but only a minority have all three.

• The commonest eye sign in Wernicke's encephalopathy is a sixth nerve (lateral rectus) palsy.

• Korsakoff syndrome is an amnestic disorder in which new memories cannot form, so delayed recall fails while working memory (forward digit span), attention and procedural memory are relatively preserved.

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Wilson's disease

• Wilson's disease is a treatable recessive disorder of copper excretion, caused by ATP7B abnormalities on chromosome 13, giving hepatic, neurological or psychiatric change in young people.

• Damage is heaviest in the lenticular nucleus (putamen plus globus pallidus), not the striatum (caudate plus putamen).

• Kayser-Fleischer rings, copper deposited in Descemet's membrane at the corneal limbus, are its characteristic eye sign.

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Infective and autoimmune causes

• HIV-associated neurocognitive disorder begins with a subcortical pattern: slowing, executive and attentional failure, retrieval-type memory loss, apathy and motor clumsiness.

• Cortical language signs such as aphasia appear late, in advanced global HIV dementia.

• Systemic lupus erythematosus causes new psychosis, mood disturbance and seizures in young women, signalled by photosensitive facial rash, inflammatory joint pain and oral ulcers.

• Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis targets GluN1 (NR1), and psychosis may precede seizures, orofacial dyskinesia, autonomic instability and reduced consciousness.

• Anti-NMDA receptor encephalitis mostly affects young women, some with an ovarian teratoma, and the electroencephalogram may show extreme delta brush.

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Other causes

• Epilepsy can cause ictal, postictal or interictal psychosis, and psychosis through forced normalisation.

• Neurodegenerative, endocrine and metabolic disease, brain injury and substance misuse or withdrawal are also causes.

Persistent delusional disorder

• Persistent delusional disorder is a non-bizarre, encapsulated delusion with preserved affect, speech and behaviour outside its theme.

• It has no hallucinations, passivity or disorganisation, and none of the wider features of schizophrenia or an organic psychosis.

Assessment and management

• Take a collateral timeline of fluctuation, seizures, illness and every medication or substance change, and examine vital signs, neurology, cognition and attention.

• Investigations follow the presentation: bloods, targeted copper, autoimmune, infection and toxicology tests, electroencephalography (generalised slowing suggests encephalopathy), imaging and lumbar puncture.

• Treat the cause, and use antipsychotics only for distress or risk, at the lowest dose for the shortest time.

• In Lewy body and Parkinson's dementias, severe neuroleptic sensitivity means avoiding routine dopamine blockade; quetiapine or clozapine may be used cautiously.