Police officers in the West Midlands are warning of a \u201cpublic health crisis\u201d over a new synthetic drug known as\u00a0monkey dust\u00a0that can be bought for as little as \u00a32.\r\nThe drug causes hallucinations and paranoia, and users have been known to climb trees and buildings and will\u00a0lash out at members of the emergency services who approach them.\r\nSo what is the drug and how big a problem is it?\r\nWhat is monkey dust?\r\nMonkey dust is also known as\u00a0MDPV\u00a0and comes as an off-white powder which can be swallowed, injected or snorted.\r\nIt\u00a0 is from a family of drugs known as\u00a0cathinones.\u00a0While\u00a0MDPV\u00a0is man-made, a so-called \u201cdesigner drug\u201d, the\u00a0cathinones\u00a0include the naturally occurring stimulant\u00a0khat, popular among some sections of the\u00a0Somali and other West African communities.\r\nBefore 2010\u00a0cathinones\u00a0could be bought in 'head shops', but they were reclassified as Class B drugs in legislation rushed through Parliament to tackle the rise of the drug, mephedrone, before a wider crack down on so-called\u00a0\u201clegal highs\u201d.\r\nThey are chemically similar to amphetamines and have similar effects. Synthetic forms like\u00a0MDPV\u00a0can be made with various tweaks in their chemical structure and can cause unpredictable effects.\r\nMDPV\u00a0 has already gained notoriety in America, where it was known as \u201cbath salts\u201d. Fears around the drug were sparked by a number of reported "cannibalism incidents". This includes the case of Miami man Rudy Eugene who was shot while naked and chewing another person\u2019s face \u2014 though\u00a0this was later put down to psychosis not linked to the drug.\u00a0Another incident with the drug led to an\u00a0elderly woman being attacked with a shovel by a man claiming to be an alien.\r\nWhat does it do?\r\nMonkey dust dampens perceptions of pain and causes powerful hallucinations which lead to severe paranoia.\r\nPolice officers report users often feel they are being chased and will lash out or climb buildings to escape, and this has led to serious falls.\r\nIn an interview with Sky News, PC Rich Frost said violent users were all too common, adding: "When you are trying to restrain them it's almost like trying to restrain someone who thinks they are the Incredible Hulk, the strength is unbelievable.\u201d\r\nThe effects can last several days and rapidly lead to addiction with meth-like withdrawal symptoms.\r\nWhy is monkey dust on the rise?\r\nDoses of the drug can be bought for as little as \u00a32 in Stoke-on-Trent and its effects can be felt even after ingesting amounts\u00a0as small as 3mg, meaning a little will go a long way and it can rapidly lead to users becoming\u00a0addicted.\r\nIts increase mirrors the growing epidemic of synthetic cannabinoids, including "spice" and "black mamba", which were also made illegal in the ban on\u00a0legal highs.\r\nHow big an issue is monkey dust?\r\nStaffordshire Police said on Friday that it has dealt with 950 calls related to the drug in the past three months, an average of 10 per day.\r\nIt was first reported as an issue in the county in 2016 but its presence has grown the force\u2019s chief superintendent, Jeff Moore, spoke out publicly this week to call for a concerted effort to stamp it out.\r\n\u201cThe drug is highly addictive and highly unpredictable, meaning emergency services can often struggle to provide the appropriate treatment to those under the influence,\u201d Chief Superintendent Moore said.\r\n\u201cEvery user acts differently, displaying behaviour that is volatile and dangerous to both the user and emergency services personnel responding."\r\nWhile Staffordshire is a known\u00a0epicentre for the drug, West Midlands Ambulance Service said it has dealt with cases across the region. Paramedics have been called to 178 incidents since April involving\u00a0monkey dust\u00a0\u2014 131 of them in North Staffordshire.\r\nIn July, Shropshire police linked a\u00a0bad batch of the drug to two deaths in Telford\u00a0and warned people not to take it. \u00a0West Mercia Police have issued similar warnings over the drug in Worcestershire.