The boy’s seizures started in childhood (v21). He was robbed of speech (v17) but was still ambulant as the spirit threw him to the ground (v18). To have acquired speech he must have been at least three or four years old when he lost his voice. He is described as a boy and therefore was less than 13 as in Jewish custom this is when one becomes a man. This history suggests tonic-clonic or grand mal convulsions.

The absence of seizures in infancy rules out disorders presenting with infantile spasms such as West Syndrome or phenylketonuria. The concurrent loss of speech suggests a secondary cause rather than primary epilepsy. Landau-Kleffner is a rare syndrome characterised by the abrupt or gradual loss of language, inattentiveness to sound, and seizures with onset in the preschool years. The combination of epilepsy and speech loss is also seen in degenerative disorders. X-linked adrenoleukodystrophy presents in children between four and eight with endocrine and neurological symptoms: initially hyperactivity, then parietal lobe dysfunction and seizures. Latterly there is rapid neurological progression with loss of speech due to bulbar muscle dysfunction and hearing loss leading to a vegetative state within two years. Tay Sachs disease is an autosomal recessive disorder found most commonly in Jews. Type II presents with progressive neurological deterioration and seizures. Ataxia and dysarthria are amongst the first signs. A primary parietal brain tumour. would also account for this picture.

But could the symptoms of epilepsy and dysarthria be due to an evil spirit? The key question to consider is whether physical and spiritual diagnoses are inter-related or not. If Satan can act by manipulating natural forces (Jb 2:7), is it not then possible that he might cause convulsions through a secondary disease process? This does not mean that Satan is directly behind every disease process, just that he may be. Though Jesus healed the boy by casting out the spirit, it is equally feasible that a dose of rectal diazepam may also have controlled the seizure. This of course would have been treating the symptoms and not the cause. In this case, Jesus dealt with the underlying spiritual cause, and we must remember that the ultimate healing that we need in a fallen world is not physical but spiritual, the ‘rebirth’ that brings us back into a right relationship with God. Christian doctors can believe that spirits can cause physical symptoms, as this is the clear teaching of the Bible. We must remember that Jesus himself concluded ‘this kind can come out only by prayer’ (Mk 9:29).