In the UK, data from the Office for National Statistics for 2001 (see England & Wales methods of suicide) showed that of the total 1,243 drug related suicides, 28.5% were due to paracetamol and its compounds, and 24.5% were by anti-depressants, making these the top two methods.
In the US (see Drug poisoning in the US), the story is similar, with the CDC reporting that the most commonly used drugs identified in drug-related suicides were psychoactive drugs, such as sedatives and antidepressants, followed by opiates and prescription pain medications.