Dementia is a generalized decline of intellect, memory, and personality, without impairment of consciousness, leading to functional impairment. 
It is a clinical syndrome, rather than a diagnosis in itself, which may cause by a variety of pathologies. Dementia is an acquire disorder, as distinct from learning disability in which impairments are present from birth, although the onset may be at any age. In a middle-aged or older person any social lapse that is out of character should always suggest dementia. 
Course: Protracted, although may be reversible in some cases. 
Sign & Symptoms of Dementia:
- Poor memory
- Impaired attention
- Aphasia, agnosia, and apraxia
- ‘Personality change’
- Odd and disorganized
- Restless, wandering
- Social withdrawal Mood
- Slow, impoverished
- Impaired. 
Causes of Dementia:
Parenchymatous brain disease:
Alzheimer’s disease, Pick’s disease, Parkins on’s disease, Huntington’s chorea, Lewy body dementia, Steel Richardson syndrome ( Progressive Supranuclear Palsy).
Multi-infarct dementia, subcortical vascular dementia ( Binswanger’s disease).
Toxic dementias :
Bromide intoxication, drugs, heavy metals, alcohol, carbon monoxide, analgesics, anti convulsants, benzodiazepines, psychotropic drugs.
Chronic hepatic or uraemic encephalopathy, dialysis dementia, Wilson’s disease.
Chronic subdural haematoma, head injury.
Potentially reversible causes:
Thyroid, parathyroid, pituitary, adrenal dysfunction.
Pernicious anaemia, pellagra, folic acid deﬁciency, thiamine deﬁciency.
Neoplasms and other intracranial space-occupying lesions.
Normal pressure hydrocephalus. 
Types of Dementia:
This is the commonest cause of dementia, seen in about 70% of all cases of dementia in USA. It is more commonly seen in women. Earlier, it was differentiated into two forms: a presenile form and a senile
form. Autopsy shows macroscopic changes such as enlarged cerebral ventricles, widened cerebral sulci and shrinkage of cerebral cortex.
Neurochemically, there is a marked decrease in brain choline acetyltransferase (CAT) with a similar decrease in brain acetylcholinesterase (AchE).
- Rivastigmine(1.5 mg twice a day to 6 mg twice a day).
- Donepezil(5-10 mg/day).
- Galantamine (4 mg twice a day to 12 mg twice a day) have used in the recent past for treatment of moderate dementia with Alzheimer’s disease.
These elevate a cetylcholine (Ach) concentrations in cerebral cortex by slowing the degradation of acetylcholine released by still intact cholinergic neurons in Alzheimer’s disease.
Memantine (5-20 mg/day), an N-methyl-Daspartate (NMDA) antagonist, is also available for the treatment of moderately severe to severe Alzheimer’s disease.
2. Multi-infarct Dementia:
Multi-infarct dementia is the second commonest cause of dementia, seen in 10-15% of all cases, though it is probably more common in India. Occurrence of multiple cerebral infarctions can lead to a progressive disruption of brain function, leading to dementia.
The most typical form of multi-infarct dementia is characterise by the following features:
1. An abrupt onset.
2. Acute exacerbations (due to repeated infarct ions).
3. Stepwise clinical deterioration (step-ladder pattern).
4. Fluctuating course.
5. Presence of hypertension (most comm only) or any other signiﬁcant cardiovascular disease.
6. History of previous stroke or transient ischemic attacks (TIAs).
Diagnosis: Emotional lability is common. EEG (showing focal area of slowing) and brain imaging (CT scan or MRI scan of brain showing multiple infarcts) help in diagnosis.
3. Hypothyroid Dementia:
This has been considered one of the most important treatable and reversible causes of dementia, second only to toxic dementias. Although it accounts for less than 1% of dementias, hypothyroidism should be suspected in every patient of dementia. Prompt treatment can reverse the dementing process and can lead to complete recovery if the treatment is start within two years of the onset of dementia.
4. AIDS Dementia Complex:
About 50-70% of patients suffering from AIDS exhibit a triad of cognitive, behavioural and motoric deﬁcits of subcortical dementia type and this is known as the AIDS-dementia complex (ADC).
As the AIDS virus (a lenti-virus, a type of retrovirus) is highly neurotropic and the virus crosses the blood-brain barrier early in the course of the disease cognitive impairment is nearly ubiquitous in AIDS.
Diagnosis: The diagnosis is establishe by ELISA (enzymelinked immuno-sorbent assay) showing anti-HIV antibodies, and the Western Blot test (blotting of antibody speciﬁcities to HIV-speciﬁc proteins). A Cranial CT scan can show cortical atrophy 1-4 months before the onset of clinical dementia while MRI scan is helpful in detecting the white matter lesions.
5. Lewy Body Dementia:
Lewy body dementia is now believe to be the second most common cause of the degenerative dementias, accounting for about 4% of all dementias.
Typically, the clinical features of Lewy body dementia include:
i. Fluctuating cognitive impairment over weeks or months, with involvement of memory and higher cortical functions (such as language, visuo-spatial ability, praxis and reasoning). Lucid intervals can be present in between ﬂ uctuations.
ii. Recurrent and detailed visual hallucinations.
iii. Spontaneous extrapyramidal or parkinsonian symptoms such as rigidity and tremors.
iv. Neuroleptic sensitivity syndrome, characterised by a marked sensitivity to the effects of typical doses of antipsychotic drugs (resulting in severe extrapyramidal side-effects with use of antipsychotics).
Other clinical features: It may include repeated falls, autonomic dysfunction (e.g. orthostatic hypotension), urinary incontinence, delusions and depressive features.
Although Lewy bodies (intra-cytoplasmic inclusion bodies) are also present in Parkinson’s disease, the occurrence of Lewy bodies in Lewy body dementia is more widespread. Antipsychotic medication should be avoided (or used with extreme caution and in low doses) in patients with Lewy body dementia.
Diagnosis: A PET (Positron Emission Tomography) or SPECT (Single Photon Emission Computerised Tomography) scan of brain may show low dopamine transporter uptake in basal ganglia. 
Diagnosis of Dementia:
According to ICD-10, the following features are required for diagnosis:
- Evidence of;
Decline in both memory and thinking, sufﬁcient enough to impair personal activities of daily living
Memory impairment (typically affecting registration, storage, and retrieval of new information though previously learned material may also be lost particularly in later stages.
Impaired thinking, presence of clear consciousness (consciousness can be impaired if delirium is also present), and a duration of at least 6 months. 
- The Mini Mental State Examination (MMSE) is used widely in assessment; it combines standard questions with tests of spatial ability, and has high sensitivity and specificity. 
- Basic Haematology
- Liver function
- Thyroid function
- Vitamin B12
A CT or MRI brain scan may be needed, as they are valuable in the diagnosis of both focal and diffuse cerebral pathology. 
Treatment of Dementia:
- Treat any physical disorders
- Psychoeducation of patient, family, and carers
- Promote and maintain independence with a written care plan
- Provide training courses and support groups for carers
- Respite care
- Palliative care input
- Structured group cognitive stimulation programme
- For agitation: aromatherapy, dance/music therapy, animal therapy
- Psychological support for carers
- Acetylcholinesterase inhibitors: (Donepezil, Galantamine, Rivastigmine) increase the concentration of and duration of action of acetylcholine in the central nervous system. There is evidence that in moderately severe Alzheimer’s disease, these drugs improve cognitive function and behaviour for up to a year. These drugs should only be prescribed by specialists, and should be stopped after 6 months if there is no clinical benefit.
- Memantine: It is a glutamine NMDA receptor antagonist which improves cognition, mood, and behaviour in moderate to severe Alzheimer’s.
- For agitation:
Antipsychotics : Antipsychotics should generally be avoided whenever possible and only have a role in patients with severely distressing symptoms or agitation causing risk to self or others. They should be avoided in those with mild to moderate dementia, as there is a slight increase in the risk of cerebrovascular events. The recommended drugs are haloperidol and olanzapine. A few patients need long-term oral antipsychotics to manage their behaviour at home.
Benzodiazepines: Benzodiazepines should be avoided wherever possible, especially during the day. Intramuscular lorazepam is a suitable alternative to an antipsychotic for extreme agitation, and should be tried if antipsychotics do not relieve the symptoms.
- For depression: antidepressants. 
Homeopathic Treatment for Dementia:
1.Dementia, due to schizophrenia-agaricus, anacardium, hyoscyamus, nux vomica, lilium tig, phosphorus.
2. Dementia after epileptic attack-aconite, belladonna, silicia.
3. Dementia due to depression-tarentula.
4. Senile dementia (Alzheimer’s disease)-agnus castus, anacardium, conium, crotalus hor, lycopodium.
5. Specific remedies, which can be given every 12 hours for up to 3 doses for dementia:
(a) Person once intellectually sharp and ambitious, now thin and withered, lacking in self-confidence, afraid of being alone, always using wrong words Lycopodium 30c.
(b) Degenerative changes in blood vessels, enlarged prostate gland, weakness and tiredness, problems exacerbated by cold Batuta 30c.
(c) Partial paralysis, blood vessels supplying brain affected by arteriosclerosis Auriuti iod 30c.
(d) Atherosclerosis, craving for salt, person highly strung and very apprehensive Phosphorus 30c. 
- Psychiatry, Fourth Edition- Oxford Medical Publications – SRG- by Geddes, Jonathan Price, Rebecca McKnight / Ch 26.
- A Short Textbook of Psychiatry by Niraj Ahuja / Ch 3.
- Homeopathy in Treatment Of Psychological Disorders by Shilpa Harwani / Ch 17.