The Affective illnesses are called endogenous depression ( endogenous = not provoked by events from without - but arising from changes somewhere within ); manic depression; puerperal depression;..... from the Guardian; Unipolar or Bipolar where the affect is on the one side or the other; Bipolar where there are moves into an overactive elated shifts, and at other times into the down moods; often mixed states and frequent shifts. between both.

I think the most important thing to state is that there is an illness of mood, that can be so enduring and disabling in it's consequence, that it must have medication or physical treatment.
Without it, the condition, although always recovering itself , can take up to two years to do that by itself.
More commonly it is a matter of months.

Whilst the state of illness is continuing, there is a risk of a move into a period of heavier burden of it, which the sufferer cannot bear.

It needs medication or other medical treatment

You cannot 'overcome' Medical mood illnesses yourself, by something you do, or things that happen to you in the ordinary way.
Medical depression has its own autonomy.
It goes along its own way.

It can be made more unbearable and difficult to get through, by misguided, often well meaning, explanations and advice about things that are recommended that the sufferer should do before relief/cure is found [ go on holiday, pull yourself together, try acropuncture hypnotherappy etc ] ; or what the sufferer should not have done, to get the condition in the first place, or to make it persist.

Very often sufferers have tried all these things and more and are in some level of despair that what helps 'normal' depression has not helpesd them.
The failure of such adice only adds, puts off real help, and worsens the burden.

The chief indication that depression is 'medical' is a significant duration of a persistent change in mental health.

Consistent in duration over three weeks

Changes in mental behaviour from before

The symptom changes now do not react as mood normally does; they persist - they have gone into their own pattern.

Medical depression is not to be defined by what appears to be the mildness or seriousness of the disability, but by the autonomous - going along on its own way - nature of the disabilities that show up the mood change. A mild medical depression which continues for weeks and months is a very definite medical condition with consequences that can be serious. It should not go unaddressed.

The changes that occur are typical.

Interest in activities, hobbies, group participitation, which was present, is lost and does not now attract or entertain.
This is so to some degree with all 'appetites' - food, sex, activities, work.
Ordinary activities carry a burden of effort.
Sleep is disturbed and this, less so in young people, is the best marker for the depression being 'medical'. It is unrefreshing, interrupted, and curtailed. The sleep disturbance is not to be seen as the cause of depression, but the consequence, and is a diagnostic for it.
Treatment for the sleeplessness is to deal with the depression not to turn to sleeping pills, in quantities,which may give the despairing the opportunity for overdose.

There is often a pattern to 'medical' depression which makes for a point of distinction from ordinary sadnesses and despairs.
In 'medical'depression the condition is usually worse in the morning and can lift appreciably in the evening. To an extent that observers in the morning get a different impression from people visiting in the evening when the mood lifts to some extent.

How to distinguish this medical mood condition from normal depression - sadness at loss and break up, overwhelming and despairing obligation to be borne without help - these hardships that have sometimes to be borne with.

In general terms those conditions can feel comforted in different settings, so that a relief for some time can be obtained, if not sustained.

There are times in the day, in some places, and in something going on, which gives an escape from the mood.

Sleep will also vary - not always broken, shortend, and unrefreshing.

An abnormal mood is stuck, and stays in Its pattern until - puzzlingly, but absolutely so - the condition goes away as puzzlingly as it started.

Whatever is being given or happening at the time of this spontaneous 'remission' , claims and gets the credit from this spontaneous resolution.
Medical mood illnesses can last from weeks,months, occasionally something like two years, but sometimes even just days [ some premenstrual depression is a remnant of endogenous depression ]- the future the duration of illness to come, cannot be known, although a past history may, but only may, be helpful.

Sadness, despair, grief, loss, debt, persistently poor or lost companionship, insufficient distancing; these are accountable. They have an undeerstandable proportionate response to a source of the reaction in the life lived. They come after a particular happening and relate to it. They call for 'professional' substitutive companionship, self examination in supportive relationships of the kind that cognitive behaviour therapy provides, or new replacement better life events-... protective cover ... ' I can't - I am seeing the doctor , the counsellor , the team , whatever ' ... -

Medical and psychiatric intervention - is temporary - using medical authority to win protection from further upset - from locally arising pressures - and to gain distancing in time and space, until better times arrive, and better supporting companionship is in place.

The abnormal mood states have no adequate explanation from what is going on in the life of the person.
That does not mean that the sufferer is free from life events. Life goes on outside the sufferer, but the mood change is not a reflection of that.
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Its autonomy overrides personality.

Because of this, insight is lost - insight and judgement is coated with the same clouding.
No reason for it; therefore no reason for it to stop.
No explanation for it; then how and why should it ever end.

Whereas an ordinary mood can be explained by an observer who knows the person and the circumstances, this abnormal state, its pattern and its duration, cannot be accounted for in that way.

Its onset and its fluctuation are inexplicable within the limits of normal explanatory usage. Its recovery - it's disappearance likewise has no explanation.

Sometimes the endogenous depresions are sub-divided - retarded, agitated, melancholic.

It is likely that these variations follow the severity of affect change and the pattern of personality; retarded in the introverted personality; agitated in the more outgoing, or those carrying high basic level of anxiety all the time.

Lesser degrees of endogenous mood change fade into normal range for observers - the milder forms can be seen as nervous anxiety and doubt. Sufferers know something is wrong but cannot announce it clearly. It is the persistence, the duration, the lack of response to natural easements, the pattern and consistency, that places the category of illness.

The milder forms can be the more 'dangerous' as they are often not taken seriously by observers; or even by the person themselves, who blame themselves for their ill state.

Agitation in outward personalities can be seen as histrionic clamouring, attention seeking - which gets rejection in our culture, and adds to the burden of the illness - when proper attention to the state is in fact what they need.

The conclusion that this is illness meets resistance all the way; and receives disappointment all along, as 'no cause' ' no explanation ' bemuses all in contact.
When sufferers get to medical contact their bewilderment often means they do not well put their case.

It may take some time to get the appropriate treatment.