46 soldiers given marching orders after drug tests
But 17 who produced positive sample allowed to stay in ranks
A total of 63 members of the Irish Army have failed drug tests for substances including cocaine and cannabis in the last five years - but just 46 were discharged from duty.
The compulsory random drug testing (CRDT) programme, introduced in 2002, is carried out on 10pc of the force each year.
The scheme is meant to act as a deterrent, according to sources, and is aimed particularly at young recruits.
The Defence Forces refused to provide a complete list of drugs tested, claiming the release of this information may "assist those intent on using prescribed substances to avoid detection".
However, it is understood legal medications that may not have been personally prescribed for a soldier are also looked for.
Defence force personnel are selected at random and must produce a sample. Those who test positive face three options: they can retire, be discharged, or face withdrawal of a cadetship.
But they can continue in service if they can make a case that taking the drug was inadvertent, or the result of some circumstance, such as consuming a spiked drink.
Those who test positive for a controlled drug are subject to an administrative process, including the testing of a 'B' sample, if so requested by individuals involved.
In certain instances, some of those disciplined as a result of a positive result have challenged the decision through the courts.
Sources stress that the taking of illegal drugs is incompatible with the ethos of military life and contrary to military law. Soldiers also have additional duties and responsibilities of care and safety, as they are frequently in charge of loaded weapons and heavy artillery.
Records show that 12 people failed a random test last year - but just seven were dismissed from the force.
In 2015, 17 failed to pass, with 12 forced to leave.
In the previous year, an illegal substance was found in five members of the force who were tested. Two of these then departed military life.
Nearly 1,000 members of the British armed forces - which have a zero-tolerance drugs policy - were found to have taken illicit substances last year.
Meanwhile, some 717 litigation claims have been brought against the authorities in Ireland by defence personnel in just two years. Bullying and harassment accounted for 37 cases. Issues arising from weapons and explosives, and post traumatic stress disorder (PTSD) are also among key categories of complaint.
PTSD occurs in response to exposure to a very stressful or traumatic event, or an exceptionally shocking, threatening or catastrophic situation.
Common symptoms include re-experiencing the event in nightmares or flashbacks. Records obtained by the Sunday Independent show 11 cases were recorded in 2014, and 14 in 2015.
In total, eight people sued for alleged sexual harassment.
A further 69 claims have been taken from current and former members of the Defence Forces who allege injury as a consequence of using the controversial anti-malaria drug Lariam. It is alleged that the drug can cause depression and panic attacks in a minority of users.
Lariam's manufacturer took it off the market in Ireland for commercial reasons last July. However, it remains available in certain other jurisdictions.
For many years the drug was given to soldiers deployed to missions in sub-Saharan Africa to prevent life-threatening illness.
There are currently three anti-malarial drugs in use by the Irish Defence Forces: Lariam (mefloquine), Malarone and Doxycycline. The decision on which medication to provide to soldiers, including the use of Lariam, is made by medical officers, and depends on the 'specific circumstances' of a mission.
In a statement, the Department of Defence said malaria was a serious disease and a threat to any military force operating in areas where it is prevalent.
"Significant precautions are taken by Irish Defence Forces medical officers in assessing the medical suitability of members of our Defence Forces to take any of the anti-malarial medications," the statement said.
It added that the health and welfare of soldiers was a "priority".