Addiction rehabilitation and treatment in Kingston and Surbiton. Teenage mental health is a topical issue, with the related problems it presents. STEM4 offers advice on addiction treatment for common addictions in teenagers, including alcohol, smoking, cannabis, amphetamines, cocaine, etc. STEM4 offers addiction advice to various target groups, preventing serious and long lasting mental health problems in teenagers throughout Kingston, Surbiton and South West London â see our range of services.