Abstract
<jats:p>Almost all psychotropics have haematology‐ or biochemistry‐related adverse effects that may be detected using routine blood tests. While many of these changes are idiosyncratic and not clinically significant, others, such as the agranulocytosis associated with agents such as clozapine, will require regular monitoring of the full blood count. Psychiatric adverse effects are poorly characterised in drug clinical trials, often only becoming apparent during post‐marketing surveillance. Given this level of uncertainty, suspected psychiatric adverse effects should be diagnosed and managed on a case‐by‐case basis. A wide range of confounding factors complicate the diagnosis (and perhaps also the recognition) of psychiatric adverse effects. For example, physical illness, co‐prescribed medication, non‐prescribed agents and pre‐existing mental illness may all influence the clinical presentation and outcome.</jats:p>