Behavioural side effect: This term refers to unwanted changes in mood, behaviour or thinking that may occur while taking a medicine. NHS information on medical cannabis includes mood and behavioural changes among possible side effects.
Important because some patients and carers notice behaviour changes before physical side effects.
NHS specifically lists behavioural or mood change, hallucinations and suicidal thoughts among possible side effects.
New agitation, distress, severe anxiety, suicidal thoughts or hallucinations warrant urgent clinical advice.