Government legal experts have ruled that there will be no criminal charges against the drug’s manufacturer, GlaxoSmithKline.
The UK drugs regulator, the MHRA, had been monitoring the safety of paroxetine since it was first licensed in the early 1990s.
An investigation by the BBC programme Panorama in 2002 highlighted public concerns about suicidal behaviour among children being treated with the drug, sparking a series of meetings between the MHRA and GSK.
It was only in February 2003 that GSK finally submitted clinical trial data to the MHRA showing that paroxetine caused suicidal ideation, and even then data from adult and paediatric trials were merged.
Full data from the clinical trials in children, demonstrating a causal link between paroxetine and suicidal ideation and behaviour, was finally submitted by GSK to the MHRA in May 2003 – a month before the company was due to submit an application for the drug to be licensed for use with children.
Findings show that ‘adverse events’ occurred in at least 2% of patients and a rate at least twice that of placebo.
These events included decreased appetite, tremor, sweating, hperkinesia, hostility, agitation, self-harm, and ‘emotional lability’.
Emotional lability was a catch-all term for a range of symptoms including suicidal thoughts, attempted suicide, mood swings, crying and self-harm.
The data also revealed doubts about the efficacy of paroxetine, which along with the evidence of suicidal behaviour, caused the MHRA to conclude that it was not safe to use on children aged under 18.
At the time, the MHRA estimated that there were 7-8,000 children aged 18 being treated with the drug.
The MHRA then launched a four-year criminal investigation into whether GSK had delayed submitting the clinical trial data – but the government has now opted not to prosecute because of legal loopholes, which are now due to be closed.
MHRA chief executive Kent Woods said: ‘We will take immediate steps to ensure the law is strengthened further, so that there can be no doubt as to companies’ obligations to report safety issues.’
GSK has rejected claims that it withheld information. Dr Alastair Benbow, medical director for GSK Europe, said: ‘We firmly believe we acted properly and responsibly in first carrying out this important clinical trials programme and then informing the regulatory agencies when we identified a potential increased risk of suicidal thinking and behaviour in patients under 18.
‘GSK is committed to working with the government, appropriate regulatory authorities and other pharmaceutical companies to take whatever action is necessary to improve legislation and policy in this area.’