Can malaria or the fever of malaria (or the medication) cause a teen to become depressed and suicidal 18 months on.
That is unlikely. Malaria, when treated, usually resolves completely, without any lingering effects. In some cases, people with severe cerebral malaria can have lasting neurological impacts, such as altered behaviour and difficulties with learning. Some studies have also shown that combat veterans who experienced cerebral malaria were more likely to suffer psychological effects after returning home, which included depression. However, again, a key feature of possible psychological conditions after malaria is that the patient experienced severe, cerebral, P. falciparum malaria. In other, non-complicated, cases of malaria, I have not found evidence for lasting psychological effects.