Tonight, I watched a sobering, but thought provoking investigation into how one defines the line between sanity and mental illness. "How Mad Are You?" was a two-part programme as part of the Horizon series on BBC 2 and tonight saw the concluding part. The show sets about identifying whether it is possible for both trained and untrained observers to identify which of 10 volunteers exhibited mental illness and which of the 6 mental illnesses these people potentially suffered from. Sound like more cheap reality TV, though I think this was very revealing.

Three professionals of distinguished psychological training were tasked with identifying the individuals and symptoms based on not having seen the individuals' history, having had no contact with the individuals and instead relying on video taped footage and 3 brief 5 minute interviews. A difficult task, if unrepresentative of the real world. The idea wasn't to show the psychologists up as being ignorant, though. The idea was to show just how possible it is to suffer from, hide (or fail to hide) or recover from mental illness.

The mental illnesses being identified were:

• Obsessive Compulsive Disorder
• Social Anxiety
• Depression
• Bi-polar disorder
• Schizophrenia
• Eating disorder

Viewers and the doctors were invited to label the volunteers as having a mental illness, and if so, which mental illness based on a series of tasks each of which specifically tailored to highlight certain traits of individuals suffering from one of the illnesses. What was alarming, however, was that as the programme briefly summarised each condition, how common the symptoms can be.

Which one of us has not been "down" in the past (depression)? Maybe we've had euphoric moments (Bi-polar)? We've all become fed up and found ourselves being insular, just wanting to avoid people (social anxiety). The programme claimed that 1 in every 10 women have suffered from eating disorders at some point in their life, is this because they decided to go on a diet now and then? We all have suspicions (Schizophrenia) and suspersitions (OCD) that affect how we go about our everyday lives, whether we consciously realise it or not. Looking at these traits, then I guess I should be locked up right away. I can put a tick in every one of those boxes.

"Obviously", I am not ill - but how do I know? At what point should I become concerned that I might be exhibiting concerning signs? In the past three years, I have been involved in a very stressful project with Work Connexions that stretched relationships both professional and personal, I have just left a job I was distinctly not happy in and I am still finding my way around an island that can be very small - you never know if people know you before you've met them! All these situations have stressed me to a point that maybe I should become concerned. Luckily, bouts of colourful language and tantrum or two, I've come out of these situations well. I don't think this is because I am a particularly strong person, mentally, so I can't see what distinguishes me from someone who may succumb to the symptoms. Which one of use can honestly say we haven't known someone who has had problems? Mental illness can touch us all and it can be devestating.

So how did I do, and how did the pscyhologists do?

Of the 6 people who had a history of mental illness, I correctly identified 4. The psychologists correctly identified just 2.

Of the 6 illnesses, I correctly "pigeon-holed" Obsessive Compulsive Disorder and Bi-polar. The psychologists also only got 2 out of 6.

Now think of it the other way round, by getting 2 right, the psychologists "labelled" 4 apparently healthy people with mental disorders. Turns out two of these people just described themselves as "quiet" or "naturally down". They were quite happy with themselves. The individuals that were not "spotted" were clearly very pleased as the work they have been undertaking in overcoming their difficulties had clearly paid off.

I can hardly claim any great degree of success in my own observations. I am increasingly getting teased that I exhibit tendencies of OCD (if liking things to be clean says I have OCD, then sign me up now) so have become aware of idiosyncracies that people may exhibit. I was pleased with my diagnosis of Bi-Polar in one of the volunteers. I made the decision early in the first programme, only going off past experience, so am quite impressed that I picked it out and kept to it throughout. The psyhologists picked it out correctly (after I had ;) ) and then changed their minds. This programme certainly brings out the amateur psychologist in you.

You can see the programmes on BBC IPlayer.