BJPsych Kaleidoscope December 2019

magazine-coverThere is enormous interest – and public pressure – about cannabis derived medicinal products (CDMPs) – since deregulation made their prescribing (at least theoretically) easier; but have we been sold a pup?

January’s Kaleidoscope reports on a systematic review and meta-analysis of the current best evidence for CDMPs in mental illness, encapsulating 83 studies (42 in depression (23 RCTs)), 31 in anxiety (17 RCTs), 8 in Tourette syndrome (2 RCTs) and 11 in psychosis (6 RCTs)). Pharmaceutical THC improved anxiety in those with chronic pain and multiple sclerosis, with or without cannabidiol (CBD). No other effects were seen anywhere else beyond a worsening of negative symptoms of psychosis. Two key findings emerge from the poor data: there is a lack of evidence, so perhaps better studies will revise this; secondly there is a lack of data on pharmaceutical CBD and medicinal cannabis (namely the full plant, with its many psychoactive components, grown in controlled conditions). Many tens of millions in the UK suffer with only partially treated conditions; the clamour for cannabis is unmatched, and seems unlikely to deliver what its most ardent proponents promise. The question remains if it might nevertheless provide comfort and treatment to some, and if so, who are they?

Antipsychotics were sometimes called ‘major tranquillisers’, though we seldom use that name anymore. However, sceptics will occasionally hurl it as a criticism that these drugs only ‘work’ through sedation.

Further, RCTs that compare antipsychotics with placebo face the challenge that side-effects might unmask participants to which intervention they are receiving, potentially skewing results in favour of the active treatment. One approach to overcome this criticism is to use active compounds in the control arm. Kaleidoscope reports on a meta-analysis of RCTs that compared antipsychotics with barbiturates or benzodiazepines in the acute treatment of schizophrenia. The results demonstrated that antipsychotics were significantly more effective than barbiturates, but there were inadequate data on benzodiazepines to draw any firm conclusions. The findings rebut the challenge that effectiveness is a result of sedation or unmasking, although it is notable that the studies included are somewhat dated; a large contemporary RCT comparing antipsychotics with benzodiazepines would be interesting.


  1. A recent meta-analysis of cannabis derived medicinal products found that pharmaceutical THC improved anxiety in those with chronic pain and multiple sclerosis.
  2. A survey has upturned water-cooler conversations and gossip to show that women perceive their ex-partners more favourably than men.
  3. The first randomised controlled trial on the topic has demonstrated clinical effectiveness in treating PTSD from physically blocking the stellate ganglion and sympathetic nervous outflow.


  1. True.
  2. False, the other way around.
  3. True.
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