To ask the Secretary of State for Defence, what guidance his Department has provided to the NHS on appropriate treatment for former Service personnel presenting with suicidal ideation resulting from brain injury caused by neurological side-effects of Lariam (Mefloquine) antimalarial prophylaxis; and how such guidance differs from that required for people experiencing purely psychiatric crises.
Mefloquine, trade name Lariam, is recommended as an effective anti-malarial by international health agencies, including the World Health Organisation. Ministry of Defence (MOD) and the National Health Service both follow National Institute for Care and Excellence guidelines on the prescription and management of side effects associated with mefloquine.
MOD is engaged with NHS England (NHSE) through the NHSE Armed Forces Clinical Reference Group. This group has reviewed the clinical management of the side effects associated with mefloquine. As symptoms can resemble acute psychiatric conditions, clinicians are advised to assess patients individually and are expected to take a full drug and alcohol history, including any previous mefloquine use.
The side effects that may be experienced whilst taking, or with a history of having taken mefloquine, will be treated according to the diagnosis; for example, if the patient is experiencing depressive symptoms, the treatment for depression will be instigated.
Since 2016, MOD has admitted mefloquine can cause minor psychiatric injury in certain individuals for a limited period of time. Causation of long-term psychiatric injury is denied.
I would encourage any Veteran who is struggling with their mental health to self-refer or seek the support of their GP to access Op COURAGE, the Veterans' Mental Health and Wellbeing Service.
Answered on 1 Jun 2026