Thespianism is a treatable condition and, as ever, the first step towards treatment is diagnosis. There are five key symptoms of Thespianism; if somebody close to you appears to be displaying these symptoms, it is essential that you consult an expert.

1. A tendency to harmonise.

Thespianism can prompt some quite unusual and, if out of tune, very disturbing behavioural patterns. Harmonising is a key character trait of most Thespians; a marked increase in harmonisation can suggest the presence of Thespianism within the individual. This is particularly true if the individual is found harmonising to West End musicals.

2. Singing, when a musical is unintentionally referenced.

Another significant behavioural pattern common to most Thespians is the singing of show-tunes at any given opportunity. To test the individual for Thespianism, try slipping a few quotes from musicals into conversation; if the individual bursts into song at any of the following references, it is highly likely that they are under the influence of Thespianism:

◦     Good morning. (Good morning!)

◦     Tonight – (tonight, it all began tonight.)

◦     Dentist – (I'll be your dentist!)

◦     Food (glorious food!),

◦     Popular – (you're gunna be pop-u-lar)

◦     At the end of the day (you're another day older.)

◦     Super – (califragilisticexpialidocious.)

◦     Only thing to do (is jump over the moon)

◦     He had it coming. (He only had himself to blame.)

◦     The hills (are alive!)

◦     Think of me; (think of me fondly.)

3. Taking offence at seemingly harmless phrases, when they are used in reference to the theatre.

The Thespian may well take offence when, for example, the terms 'half-time' and 'practice' are used instead of 'interval' and 'rehearsal'. Recording how the individual reacts when exposed to such phrases could be very useful to an expert, later on.

4. Having an unusual understanding of the 'celebrity' concept.

To the Thespian, West End and Broadway stars will be considered the ultimate celebrities. Furthermore, the Thespian may be entirely unaware of other 'celebrities', if they haven't appeared on stage; the individual can therefore seem, at times, slightly confused and disorientated during conversations about off-stage personalities.

5. Knowing several facts about theatre and/or individual shows.

The knowing of theatrical facts is a definite symptom of Thespianism. The individual may try to slip these facts into every day conversation, but it is more likely that a trigger will set them off.

The trigger: Triggers can take numerous forms, and are often unintentional; they can therefore be hard to spot. Do not be concerned if you don't understand why a certain trigger led to the spewing of theatrical facts; often such things only make sense to the true Thespian.

Is somebody that you care for displaying these symptoms?

Thespianism may seem like something that could never affect you, or somebody close to you, but very few people can withstand the condition, when they are expose to the stage. The sooner your loved on is diagnosed, the better.

If you have observed any other symptoms of Thespianism, please post them on a comment so that we can better understand the condition that is fast becoming a theatrical epidemic.

• Features