The rate of drug-related deaths in the Derry and Strabane decreased over the middle years of the last decade.
There were nine deaths in the Local Government District in 2014, a rate of six fatalities per 100,000 people.
But in 2018 there were eight deaths; 5.3 per capita.
Derry and Strabane was one of only two districts - Mid Ulster was the other - where there was a decrease over the five year period.
Higher rates, however, were recorded in 2015 (11 deaths; 7.4 per 100,000), 2016 (12 deaths; 8 per 100,000) and 2017 (9 deaths; 6 per 100,000).
The figures have been newly-released by the Northern Ireland Research and Statistics Agency (NISRA).
The data show that while Derry and Strabane experienced a dip in deaths there was an increase across the Western Trust area.
Across the health authority the number of deaths rose from 15 in 2014 to 20 in 2020.
The rate of death thus increased from five fatalities per 100,000 people in 2014 to 6.6 deaths in 2018.
Across the North as a whole there were 189 drug-related deaths registered in 2018.
Half (95) of these deaths were of men aged 25-44.
The 2018 total (189) is more than double that recorded a decade ago (89) and has risen by 39.0 per cent over the year, from 136 in 2017.
Drug-related deaths accounted for 10.0 deaths per 100,000 people in 2018.
In terms of all deaths registered in the North in 2018 (15,922), drug-related deaths accounted for 1.2 per cent of the total.
The figures further show that between 2017 and 2018 the drug-related mortality rate increased for both males and females.
The rate for males increased from 11.0 per 100,000 males to 14.4; for females the equivalent rate rose from 3.7 per 100,000 females to 5.9.
Males accounted for 70.4 per cent (133) of the 189 drug-related deaths registered in the North in 2018.
Of the 189 drug-related deaths in 2018, 72 (38.1%) were in the 25-34 age group with a further 50 (26.5%) in the 35-44 age group.
These figures equate to age-specific, drug-related mortality rates of 29.0 deaths per 100,000 people, aged 25-34 and 20.9 deaths per 100,000 people, aged 35-44.
More than eighty five per cent (161) of all drug-related deaths in 2018 were classed as drug-misuse deaths, compared with 59.6 per cent (53) in 2008.
The rate of death relating to drug-misuse increased from 3.0 deaths per 100,000 people in 2008 to 8.6 deaths per 100,000 people in 2018.
Half of drug-related deaths in 2018 involved three or more drugs. In contrast, in 2008 almost half of drug-related deaths involved one drug.
Since 2010, over half of drug-related deaths each year have involved an opioid.
In 2018, a total of 115 drug-related deaths had an opioid mentioned on the death certificate.
Heroin and morphine were the most frequently mentioned opioids in 2018, connected to 40 drug-related deaths, up from 24 in 2017 and the highest number on record.
Drug-related deaths involving cocaine increased from 13 in 2017 to 28 in 2018 and is the highest level on record.
Diazepam was listed in 40.2 per cent of all drug-related deaths in 2018, a similar proportion to that recorded in previous years.
Drug-related deaths involving pregabalin, however, have risen consistently since its first appearance in these statistics in 2013; the annual number of deaths involving this controlled substance rose from 9 in 2016, to 33 in 2017 and 54 in 2018.
The latest figure sees pregabalin appearing in 28.6% of all drug related deaths.
Almost twenty three per cent of all drug-related deaths in 2018 also mentioned alcohol on the death certificate, a proportion which has remained relatively consistent over the last five years.
The statistics also indicate that there are notably higher numbers of drug-related deaths in areas of deprivation across the North.
People living in the most deprived areas are five times more likely to die from a drug-related death than those in the least deprived areas.