River Dart in Totnes searched for 'legal high' teenager Published duration 6 August 2016

image copyright Devon & Cornwall Police image caption Police believe the so-called "new psychoactive substance" (NPS) that Nathan Wood is suspected to have taken caused a change in his behaviour

Search teams are continuing to look for a teenager feared to have fallen into a river after taking a so-called "new psychoactive substance" (NPS).

Nathan Wood, 16, was reportedly seen running naked near the River Dart in Totnes on Friday evening in a "distressed state", police said.

Officers said they believed he entered the water at about 18:30 BST on Friday.

Divers, the Dartmoor Rescue Group and a helicopter were drafted in on Saturday to help find Mr Wood.

media caption The BBC's Andy Birkett said rescue crews were finding it easier to search the river area in daylight

Acting Sgt Kevin Rowe, of Devon and Cornwall Police, told the BBC the boy had been with a group of friends.

Sgt Rowe said there was a "possibility he may have taken some sort of [formerly] legal high which has had an adverse effect on his behaviour and caused him to behave quite irrationally".

New psychoactive substances, formerly known as "legal highs", are synthetic versions of drugs such as amphetamines and cannabis designed to mimic their effects.