Disclaimer: This is not intended as medical advice but for informational purposes only.
Depression
Extremely common in hospital. Often difficult to detect because it is normal to feel ‘depressed’ when unwell as part of the physiological response to acute disease. The problem comes when the depression persists long after the acute illness has recovered. The reasons are multifactorial and include the environment they are in, chronic disease factors, nutrition, social factors, previous history, reaction to loss, employment, financial problems… the list is long.
The question is how can patient’s be helped. Oftentimes the best thing is to get out of hospital and back into normal life environments. However, sometimes the depression may actually impair recovery and lead to delays in getting home, particularly in the elderly.
The most important thing is to recognise the problem and offer people support and also relationships where they feel they can trust those caring for them. Medication and psychiatric support may play a role depending on the severity of the condition but should not be a first resort.
Delirium
Delirium is extremely common in hospital.
It is associated with significantly worsened outcomes and tends to affect those at the extremes of age:
It makes it extremely difficult for people to ‘filter’ out irrelevant noise. Delirious people struggle to cope with disturbances and lots of stimulation. It tends to exacerbate the problem.
Therefore the aim of treatment is to keep things calm, quiet, well lit, constant, with good feeding, sleep hygeine and the ability for the person to explore.
Dementia
Becoming increasingly common in hospital. Management principles are related to those for delirium except that complete neurological recovery is not anticipated.
The difficulty comes when people lack capacity to make decisions regarding their care, finances, discharge and other major questions. In the UK if you are over 16 years old you are presumed to have capacity to make your own decisions. Capacity is decision specific. A person with dementia can have capacity over some decisions in their life like what decisions they would like to take over their own health, but that same person may lack the capacity to manage their finances or discharge destination. It is also time specific: ie. It can fluctuate and vary during the day or week. This is why it is so hard to measure.
A common sense approach is reasonable most of the time; The baseline assumption is that people have capacity, even to make what others may consider to be foolish decisions. However, if there is doubt the following rules should be tested: 1) Does the patient have the ability to understand the information?, 2) Can they retain the information long enough to make a decision? 3) Can they weigh it up (pros and cons) in order to make that decision – note their logic doesn’t have to be the same as yours!, 4) Can they communicate their decision?

Every effort has to be made to facilitate the above. However, if there is compelling evidence that someone cannot perform the above (normally most of the issues are to do with retaining the information). The gravity/severity of the decisions are also key factors that have to be considered and if there is doubt second and third opinions may be needed. If there is time it is better to involve all the key parties.
This above all the other areas is the most tricky and thorny part of psychiatry in hospital. It takes a lot of time and discussion; but with good planning, forethought and involvement with key stakeholders often the situation becomes clear over time.