Schizophrenia: Definition, symptoms, subtypes and key to diagnosis

Schizophrenia is a psychotic disorder in which the term literally means 'split mind,' this is because there is a split between emotion and cognition.

The prevalence of schizophrenia is around 1/100 meaning that it affects around 1% of the population. It is no more or less common in men or women but is instead equally common, however, men do tend to experience more severe cases of the illness. In addition to this, men are usually diagnosed earlier than women. Men tend to be diagnosed in their late teens to early twenties while women tend to be diagnosed late- from their mid twenties to early thirties.

Despite the illness having a prevalence of 1% identical twins have a concordance rate of 48% Meaning that if one twin is diagnosed then there is nearly a 50% chance that the other twin will be diagnosed at some point in their lives too.

Symptoms of schizphrenia can be classified as positive or negative. Obviously positive does not refer to 'good' symptoms and negative refer to 'bad' symptoms as all symptoms of schizophrenia are awful to suffer. Instead positive symptoms refers to the acquistion of abnormal functioning/behaviour and negative symptoms refers to the loss of normal functions.

Hallucinations: These are false sensations that have no identifiable source. The most common form of hallucination are auditory i.e. hearing things that are not there and have no source and visual hallucinations which is literally seeing things which are not in reality present. Other types of hallucinations can be olfactory (smelling things which are not really present) or tactile (believing something is touching you when really nothing is.)

Delusions: This is when situations or other things are misinterpreted so false beliefs are created without a basis of fact or evidence. As with hallucinations there are a variety of different types of delusions. Delusions of grandeur which is believing that you have great power, status or important-an example of this would be completely believing that you are Jesus. Delusions of persecution are believing that you are being victimised or spied on for example you may think that while you're walking down the street MI5 are following you or that your house has been bugged so people can listen to what you're doing. Delusions of control are when you believe that your thoughts/actions are being controlled by others for example aliens or just another person.

Disorganised Speech: This is when the sufferer acquires communication problems which makes them hard to understand. An example of a type of this would be making loose associations where the sufferer switches rapidly between topics that are clearly not linked. Additionally the sufferer may create neologisms which are made up words that only they can understand. And finally they may start speaking with lots of clang associations which is where the person will repeat rhyming words in a conversation.

Mutism: Another term for this is 'poverty of speech,' and it is when there is a reduction in communication. An example of this is giving short, empty responses to questions which is thought to result from slowing or blocking thoughts. Although mutism can also also manifest by a total loss of speech.

Flat Effect: This is a reduction in emotional expression. The persons tone of voice is often monotone and facial expressions do not alter much and are in general less intense- thus making the sufferer appear 'flat.'

Social Withdrawal: As the name suggests this is when the sufferer chooses to spend a large proportion of their time alone and has little or no interest in being around others. In essence the person completely isolates themself away from society.

As well as positive and negative symptoms there are also several others which a schizophrenic may suffer from.

Inappropriate Affect: This is when emotional responses/expressions are unsuitable for the situation. For example laughing when someone tells you that a loved relative of theirs has died.

Catatonia: This is abnormal movement (a psychomotor symptom) and tends to involve either extreme rigidity or extreme flexibility of limbs. Catatonic rigidity is when the person stays complete still and their limbs are hard to move out of the position they have stopped in, sufferers can remain in rigid positions of minutes or even hours at a time. Catatonic excitement is when the sufferer shows wild and uncontrollable motor movements such as flayling limbs. Also, a sufferer can alternate between the two.

There are many different types of schizophrenia, all of which have different symptoms.

Disorganised: Disorganised or muddled speech and behaviour is common along with random giggling, pulling faces and flat/inappropriate effect.

Residual: With this type the signs of the symptoms are still present but are reduced and much less intense. People in this category are not 'cured' but are not 'fully active.' Hence the symptoms are in a less severe state.

Catatonic: Sufferers may experience catatonic stupors where they spend long periods of time rigid and immobile or may suffer from catatonic excitement where they show wild and uncontrollable motor movements. It is not uncommon for sufferers to alternate between the two different types of catatonia.

Undifferentiated: These sufferers do not typically fit into any other subtype. The symptoms these sufferers show are often drawn from all other subtypes so they show a wide variety of different symptoms.

Paranoid: The main features of this subtype are delusions and hallucinations. With regards to delusions they are normally delusions of persecution so they person believes that they are being plotted against or persecuted in some way. And with regards to hallucinations they tend to be auditory. With this subtype sufferers are often agitated, angry, argumentative and highly suspicious of others.

For a diagnosis to be made there are some criteria that need to be fulfilled as according to the DSM IV (Diagnostic and Statistical Manual of Mental Disorders edition 4.)

Characteristic Symptoms: Two or more symptoms are needed to be present for 1 month, this includes: delusions, hallucinations, disorganised speech, disorganised/catatonic behaviour or negative symptoms. However, only one symptom is required for diagnosis if hallucinations/delusions are 'bizarre.' You may be asking what defines 'bizarre' but I will answer this question in the next hub. (Criteria A)

Social/occupational dysfunction: This must be present for 6 months. There must also be evidence that work, interpersonal relations and self care must be much lower than before the onset of the illness. (Criteria B)

Duration: Symptoms from Criteria A must be present for 1 month. And symptoms for Criteria B must be present for 6 months. (Criteria C)

Schizoaffective & mood disorder exclusion: Schizophrenia can only be diagnosed if schizoaffective or mood disorder is rules out. This can only be done if the patient did not experience depressive, manic or mixed episodes at the same time as experiencing the symptoms for criteria A. (Criteria D)

Substance/general medical condition exclusion: Schizophrenia could be diagnosed if the disturbance is not due to any physiological effects e.g. of a substance, medication or a general medical condition. (Criteria E)

Relationship to a pervasive developmental disorder: If a history of Autistic disorder or another pervasive developmental disorder is present, schizophrenia is only diagnosed if prominent hallucinations or delusions are also present for at least one month-less than one month if being successfully treated. (Criteria F)