2.4 Treating depression: the 1990s
The first SSRI (zimeldine) was introduced in 1980, but withdrawn soon afterwards when found to cause a very small but unacceptably high number of serious neurological and other reactions. Next came fluvoxamine (Faverin/Luvox, Solvay), but it was no breakthrough. At launch it was oversold (DTB, 1988) and promoted for a wide range of somatic complaints which might (or might not) be linked to depression, including "aches and pains, agitation, anxiety, sleep loss, low mood, dizziness, worry, sweating" etc. (Duphar, 1987) Also its adverse effects had been underestimated and it ran into bad publicity in the lay media (Ferriman, 1988) after a warning about suspected adverse effects from the Committee on Safety of Medicines (1988).
Fluoxetine was launched in 1988/89. Prozac became a buy-word and the main driving force behind the huge expansion of the depression market. Here is a drug immortalised by Woody Allen (as Valium was before it) and the subject of overwhelming volumes of airtime and webspace, and countless miles of print. Ten popular books with "Prozac" in the title have been referred to in this paper, but there are at least twice that number, in English alone. (Baker & Taylor, 1996)
Along with fluoxetine there are now several other SSRIs and related drugs and the value of the world market (1997) is about £3bn a year. The table shows how Prozac and the others have almost doubled the size of the antidepressant market in England (Department of Health, 1991-1998). The SSRIs have yet not significantly eroded prescribing levels for other antidepressants (as they now have in the US); the whole market dramatically expanded once they arrived on the scene.
NUMBER/COST OF NHS PRESCRIPTIONS (ENGLAND), ANTIDEPRESSANTS & SSRIs
1991 1993 1995 1997 1999 2000 2001 2002 Prescriptions (m) for all antidepressants 8.9 10.8 13.2 16.8 20.1 22.0 24.3 26.3 Prescriptions (m) for SSRIs etc. (% of total) 0.5 (1%) 1.7 (16%) 4.2 (32%) 7.0 (42%) 9.8 (49%) 11.6 (52.7) 13.7
15.5 (58.9) NHS spend: all antidepressants £54m £99m £147m £239m £315m £310 £342 £381 NHS spend on SSRIs etc (% of total) £18m (33%) £53m (54%) £107m (73%) £196m (82%) £262m (83%) £253m (82%) £284
Source: Prescription Cost Analysis (England), Dept of Health Statistics Division, 1991-2003
Click HERE to see 1997 to 2002 sales levels of individual SSRIs
Underlying the success of the SSRIs was the still widely-promoted theory that depression was in effect a serotonin deficiency disease. The thrust of the message was that depression is as biological in origin as is lack of insulin for someone with diabetes - the implication being that drugs like Prozac might be considered almost as essential supplements for people with depression. Though still strongly supported and promoted (See 3.6), the idea that depression has more complex and varied biological origins is said to be gaining ground (Delgado et al., 1992).
Genetic and biological factors can have an important role in depression, but the notion that depression is basically caused by lack of brain serotonin (or some simple imbalance with other neurotransmitters) is clearly problematic. It does not explain, for example, why drugs which have an immediate effect in raising brain serotonin levels nevertheless usually take at least a couple of weeks to exert an antidepressant effect. Nor would it explain why SSRIs have no more effect on depression than other antidepressants which hardly act on serotonin. And how would one explain the lack of effect of antidepressants on the most clear-cut cases of depression, the roughly one-quarter of all cases most resistant to treatment with drugs ? Such theories are widely supported, but their scientific basis is indeed questionable:
" ... far from these hypotheses being an unambiguous advance in the scientific understanding of mental illness, I have argued elsewhere (1987) that the monoamine hypotheses in particular were quite simplistic; that they accounted for less of the clinical data and were as unscientific as the psychodynamic hypotheses before them, in that they have been in practice, incapable of disproof". (Healy, 1990)
Several other recent developments helped the SSRIs to become established. One was the belated recognition of the benzodiazepine (BDZ) dependence problem: in the late 1980s, new curbs on tranquilliser prescribing opened up the market for medicines for anxiety, insomnia and the like. (CSM, 1988) Secondly, there were concerted professional initiatives to encourage both patients and doctors to recognise and treat depression more aggressively. Thirdly, experts rewrote and transformed the treatment guidelines for depression. Other experts formally redefined the condition known as "depression", emphasising the need for prolonged treatment and linking it more closely to the kinds symptoms for which BDZs had hitherto been almost exclusively used.
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