Comorbidity is common: the patient may have both somatic and psychiatric problems. The knowledge of a serious disease and the limitations due to the disease predispose to mental disorders. Furthermore, mentally retarded patients and patients with dementia are at risk of psychiatric disturbance.
When to suspect a somatic aetiology for a mental disorder
In delirium, especially if an elderly person without a psychiatric history develops an acute confusional state
In psychosis that is not functional by certainty, especially if the patient has not had a psychosis before
Unusual age of onset of a mental disorder: for example, first-episode psychosis, obsessive-compulsive symptoms or bipolar disorder that begins in a person over 40 years of age
Any mental symptoms in an aging patient who was previously in good mental health may be the first sign of an incipient memory disease.
The patient also develops a neurological sign in addition to mental symptoms (e.g. paresis, epileptic seizure, cranial nerve sign).
There are also symptoms of infection.
The patient has a history of any recent brain disease or head injury.
The patient has a significant organic disease (diabetes, hypertension, cardiac insufficiency, atrial fibrillation, renal or hepatic insufficiency etc.).
The psychiatric symptoms do not respond to therapy in the usual manner (e.g. depression refractory to therapy).
There are olfactory or visual hallusinations.
Organic personality change
Any brain disease may, by damaging the neural networks in charge of behavioural and emotional control, cause symptoms that are manifested as change of personality. The patient him-/herself is rarely conscious of the change, but it is apparent to the significant others. Particularly brain tumours, frontotemporal degeneration, brain injuries, as well as frontal infarctions and haemorrhages may be behind the change.
Typical personality changes caused by a neurological disease are apathy (loss of interest and initiative, flattening of emotions and nuances of personality), disturbances of impulse control (e.g. hypersexuality or substance abuse), lack of empathy, unsocial or careless behaviour and features of suspiciousness in behaviour.
Secondary depression
Depressive symptoms are clearly more common in persons with a brain disease than in others. This is thought to derive from, in addition to the disability caused by the disease, the damaging effect of the disease on the neural networks that control emotions.
The treatment of this so-called secondary depression is not different from that of other depressive disorders, but it is often more refractory to treatment.
Compared with general population, depression requiring therapy is reported to be 4-10-fold more common in the subacute phase of a stroke, in patients with a brain tumour, in association with brain injury sequelae, in epilepsy patients with poor seizure control, as well as in patients with Parkinson's disease or MS. The prevalence of severe depression in the adolescent and adult population is about 5-7%.
Somatic disorders that may cause the patient to be referred first to psychiatric treatment
Infections
General infection
In the elderly and in those who are in poor health (pneumonia, upper urinary tract infection, sepsis)
Infections of the central nervous system
Encephalitis Encephalitis may begin with mental changes that resemble acute psychosis.
Meningitis Meningitis in Adults is usually associated with symptoms of general infection, like fever, headache, neck stiffness and clear deterioration of general condition, in addition to mental confusion.
Syphilis with symptoms in the nervous system is still seen Encephalitis.
Subacute sclerosing panencephalitis (SSPE) may start with symptoms resembling psychosis Encephalitis.
Advanced HIV infection may be accompanied by various types of memory symptoms, depression, personality changes, and even psychosis.
Metabolic disorders
Both hypoglycaemia and hyperglycaemia may be manifested as confusion, anxiety and e.g. aggressive behaviour.
Disorders of water balance, e.g. hypo- and hypernatraemia and hypo- and hyperkalaemia may trigger acute confusion.
Thyroid disorders: hypothyroidism may cause depression, retardation of mental functions and even a memory disease among the elderly. Hyperthyroidism is characterized by agitation and insomnia.
Hypercalcaemia (adenoma in the parathyroid gland) may result in symptoms interpreted as depression.
Hepatic coma and also milder hepatic failure causes changes of consciousness. The patient normally has a known history of liver disease or severe alcoholism.
Vitamin B12 deficiency causes impairment of memory.
Medication and substance-related disorders
Confusion can be related to an abnormal susceptibility to the adverse effects of medication used according to instructions (glucocorticoid, for example) or to overuse of medication (see also delirium Delirium in the Elderly).
Alcohol abuse may be well concealed, especially in women and in the elderly.
If alcohol abuse is known, Wernicke-Korsakoff's disease Neurological Disorders and Alcohol should be kept in mind. As a precautionary measure, thiamine at minimum 250 mg i.m. or i.v. is immediately administered to patients arriving in the emergency department if excessive alcohol consumption is suspected.
When encountering a confused or strangely acting patient, keep in mind also
interactions of pharmaceuticals and natural health products; for example St. John's wort, medications for treating migraine attacks and SSRI antidepressants may all affect the serotonin system.
Epileptic seizure, temporal epilepsy, postictal state
Especially if the patient has unusual behaviour appearing as fits, the cause may be a polymorphic focal epileptic seizure. Often it is already known that the patient has epilepsy. An EEG taken during the seizure may clarify the situation.
Some patients with temporal epilepsy have visual or auditory hallucinations and phobias as prodromal symptoms.
Certain epileptic patients may have post-ictal confusion after seizures. This may last up to several hours during which they may act aggressively.
A cerebral infarction in an elderly person may present only with confusion without other signs.
Infarction in the right (non-dominant) hemisphere affects the spatial sense. The patient may have a feeling of strangeness in the environment and may give an impression of a psychiatic disorder if there are no other signs of stroke.
Infarction in the left (dominant) hemisphere may cause only sensory dysphasia (inability to understand speech while the patient's own speech is moderately normal), which may resemble a psychiatric disorder.
Intra-cranial expansions
A frontal lobe tumour may cause a slow change in personality. Symptoms may include slowness and deterioration of thinking. On the other hand, there may be disinhibited behaviour, loss of judgement and sometimes deteriorated sense of smell.
A temporal lobe tumour may also produce personality changes and often causes epileptic seizures, which may not present as convulsions but as psychogenic symptoms.
Chronic subdural haematoma Traumatic Cerebral Haemorrhages may cause slowness and deterioration of mental capacity that worsens gradually over weeks or months. It is often accompanied by nausea, headache and fluctuations in consciousness. The patients are often elderly people or alcoholics.
Epidural haematoma Traumatic Cerebral Haemorrhages and subacute subdural haematoma should be considered as causes of sudden confusion. Usually there are accompanying signs, such as headache and changes of consciousness.
Memory diseases
Vascular cognitive impairment Vascular Cognitive Impairment (Vci) may sometimes initially cause depression and states of confusion in association with new brain infarctions before clinical neurological signs and dementia can be detected.
Alzheimer's disease Alzheimer's Disease is associated with several psychiatric symptoms.
Depression is common in the early stages of disease.
Memory impairment may be manifested as, for example, paranoid symptoms. The patient may cover up memory gaps by fabrications that he/she him-/herself believes in (confabulation).
In the moderately severe phase many patients become anxious and restless. Many patients also suffer from insomnia.
In the moderate to severe phases behavioural disorders, such as soiling, wandering, uncontrolled aggressivity, running, and constant dressing and undressing or eating disorders are often present.
Lewy body dementia Parkinson's Disease Dementia and Dementia with Lewy Bodies includes, in addition to memory impairment, also visual disturbances and rigidity, which may be confused with depression. The patients are sensitive to antipsychotic drugs, which may cause extrapyramidal symptoms, and to antiparkinsonian medications, which may trigger a state of confusion. The patients often also have the so-called REM sleep behaviour disorder (RBD), which may, during sleep, manifest as intense or aggressive motoric restlessness that sometimes may be erroneously interpreted as psychotic.
Creutzfeldt-Jakob disease Uncommon Infections of the Central Nervous System is characterized by rapidly progressing dementia accompanied by neurological signs (paralysis, extrapyramidal signs, myoclonus). In the early stage the disease can be interpreted as psychiatric disorder.
Huntington's disease is often first diagnosed as psychosis, even as schizophrenia. Patients are lively and overactive. The development of choreiform movements and knowledge of similar disease in the family help in establishing the diagnosis.
Polycystic lipomembranous osteodysplasia with sclerosing leucoencephalopathy (PLO, Nasu-Hakola disease; see also Parkinson's Disease Dementia and Dementia with Lewy Bodies) is a rare disease causing primarily frontal lobe cerebral degeneration as well as bone cysts. In the initial phase the patients are full of action and behave uncontrollably.
Confusion due to medication of Parkinson's disease
In severe Parkinson's disease the patient may need abundant medication with usually dopaminergic drugs (levodopa, MAO-B inhibitors, dopamine agonists and COMT inhibitors) and anticholinergic drugs (classic antiparkinsonian drugs) to maintain his or her ability to move. As a result of synergism a state of confusion may develop, possibly triggered by addition of a new drug.
The confusion caused by levodopa and dopamine agonists is often accompanied by hallucinations in which the patient sees his or her relatives, dead or distant, and is aware that these sights are hallucinations.
Dopaminergic medication (dopamine antagonists in particular) may, even when smaller doses are used and already in the early phases of the disease, trigger disorders of impulse control, such as gambling or hypersexual behaviour, or (most commonly) a manic psychosis.
The treatment is a reduction of medication, which may lead to reduced ability to move. A balance must be sought in the level of medication: either the patient can move more easily but becomes confused or cannot move but avoids confusion.