Polar bears, dogs, parrots, grandparents and children may all become depressed at some time. It is known that when polar bears are threatened as the ice cap melts so their mood changes. Anyone who has owned dogs knows that they react to changes in their environment by showing signs and symptoms such as those described by patients to doctors at every surgery.

When a parrot is depressed it not only goes off its food, looks mopey, but becomes crotchety too and may nip without good reason.

It is a myth that children don’t become depressed; the problem is how to treat them and what induced the depression. It is the underlying cause that should determine the treatment. Usually there isn’t any debate about the diagnosis. The behaviour of depressed children is like that of miserable cats: in both cases it may become unpredictable.

Depressed adolescents with Down’s syndrome may not sit around moping, but often become aggressive and difficult so that once-jolly teenagers start lashing out and being abusive. Tranquillisers might seem an obvious treatment, but these can make them worse, whereas antidepressants may remove aggression.

Depression isn’t a complete diagnosis, but the description of someone’s mood. It is not a disease but a symptom found in many different syndromes. Even when used to describe how a person is feeling the term may not be medically accurate. Often people don’t distinguish someone who is acutely, or even chronically, clinically depressed, from those who are suffering from dysthymia.

Dysthymia is the term used to describe the lesser mood change that leaves someone perpetually dreary and wanting, forever suffering from the blues and feeling down. Their symptoms are not usually severe enough to be described as clinical depression and to warrant the use of drugs. But, surprisingly, some patients with dysthymia respond to Prozac.

Equally confusingly, some people who are usually extrovert, goal-orientated and full of energy do their best to hide their depression because to them the symptom is a sign of weakness and they play down their misery and force themselves to smile. They are the smiling depressives who won’t admit to being depressed and are a trap for the unwary doctor. As a result both groups may be undertreated – sometimes with tragic results.

When I started in medicine the first antidepressants (the tricyclics) had only recently been introduced. They were considered wonder drugs that would empty asylums. Like all successful fashions they were soon overused.

People often debate what would have happened to Van Gogh’s art if his doctor had treated him with modern antidepressants. The discussion shouldn’t centre on his artistic flair, but on the effect treatment would have had on his behaviour. Would antidepressants have made him more agitated, aggressive and obviously crazy? To have given Van Gogh Prozac, without any accompanying antipsychotic or similar drug, would have been to risk immediate disaster – Prozac can induce hyper-mania in some people. Van Gogh’s first incident of self-mutilation might then not just have resulted in a missing ear.

It might not have been a question of whether his genius was smothered and the edge taken off his art, although this could have happened, but would the Prozac have induced violence, suicide or even murder? Although the first antidepressants initially seemed like miracle drugs that helped the endogenous depressive – the person with the inexplicable early morning waking, who has lost appetite, weight and sexual drive and for whom life seems irretrievably hopeless – their weaknesses soon became apparent. They could also be life-saving occasionally for those who were severely and persistently depressed. Antidepressants often didn’t help and at that time weren’t usually given to the inadequate or histrionic.

Prozac and the other SSRIs – the 5HT reuptake inhibitors – largely replaced the tricyclics. They had fewer potentially dangerous side-effects. They soon became grossly overused, diagnosis became sloppy and they were given to the inadequate, who then felt worse because of side-effects. If given to a patient with bipolar disease without other cover they could trigger suicidal or violent behaviour. Misdiagnosis of depression, and the consequent misuse of antidepressants, makes excellent TV, but underrates a useful life-saving – when properly prescribed – group of drugs.

Explore Health

• Expert Advice

• Health Features

• Mental Health

• Alternative Medicine

• Child Health

• Health Club