cpdclinicalbiochem.co.ukCPDCLINICALBIOCHEM.CO.UKCPDCLINICALBIOCHEM.CO.UK3008-044410.61336/cpdcb/2024-01-10Legal Highs - Not so new and still growing in popularityFrancis J NoneDunneKhalid NoneJaffarShazia NoneHashmiFRCPsych, Consultant Psychiatrist, Havering Community Recovery Team, 137-145 Church Road, Romford, Essex RM3 0SH.MRCPsych, Specialist Registrar ST6, Havering Community Recovery Team, 137-145 Church Road, Romford, Essex RM3 0SH.Designer or synthetic drugs which include legal highs and other “club drugs” are substances which have a propensity to cause euphoria, central nervous system stimulation, and hallucinations. Based on chemical formulae for opioids, mescaline, and cannabis, they are created in laboratories under lax conditions for no defined medical purposes. Because they vary in composition from batch to batch they are potentially dangerous for users. Furthermore, the chemical structure is continually changing in order to avoid legislation and therefore users can never be sure what they are taking. For the purpose of this article readers should use the terms legal highs, designer drugs, bath salts, herbal highs, ‘research’ chemicals, and novel psychoactive substances, interchangeably. Their main purpose is to induce psychoactive effects that mimic amphetamines, cannabinoids or psychedelic drugs. The term ‘research’ only infers that very little is known about these substances and information on adverse effects is often sparse. The reader should also bear in mind that it is beyond the scope of this article to include many other agents.