 LQD is a multicentre randomised clinical trial comparing the clinical and cost effectiveness of lithium versus quetiapine when used as add-on therapies to antidepressant medication for patients with treatment resistant depression. The Lithium versus Quetiapine in Depression LQD study will assess patients over 12 months to establish which if any treatment is more likely to improve TRD over a long duration of time. Professor Anthony Cleare is the Chief Investigator and recruitment is due to start in November 2016. Recruitment will begin in London, followed by additional sites in Newcastle and Oxford in early 2017. 