Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
10.3 Major clinical issues with somatoform disorders and cannabis/ hallucinogen use
- There is currently little rigorous evidence to indicate what the role of cannabis might be in managing pain.
- In the absence of other proven forms of treatment, CBT is, at present, the most widely employed form of treatment for cannabis use.
- Somatoform disorders are best managed behaviourally and with cognitive therapy.
10.3.1 Effects of cannabis and other hallucinogens on somatoform disorders
- Cannabis may have a beneficial effect on pain(409). However, there is currently little rigorous evidence (by way of randomised controlled trials) to indicate what the role of cannabis might be in managing pain(410-414).
- Despite this, cannabis is one of the most commonly used substances among individuals with somatoform disorders(415). It may be used by individuals with somatoform or pain disorders in an attempt to alleviate pain or as an antiemetic to relieve nausea associated with opioid use(409, 412, 416).
10.3.2 Interactions between cannabis and therapeutic agents for somatoform disorders
- Cannabis can exacerbate the sedative effects of tricyclic antidepressants and benzodiazepines which increase the risk of impaired driving and injury as well as overdosex.
- Cannabis, benzodiazepines, opioids and antidepressants are metabolised by CYP 450 enzymes which may result in the inhibition or induction of each drug group. Therefore, individuals should be monitored closely to ensure outcomes are appropriate and people are not experiencing increased sedationx.
10.3.3 Management approaches for comorbid somatoform disorders and cannabis and other hallucinogen use
- Abstinence from cannabis is a difficult goal to achieve in cannabis dependent people(128).
- In the absence of other proven forms of treatment, CBT is, at present, the most widely employed form of treatment for cannabis use****(128).
- Somatoform disorders are best managed behaviourally and with cognitive therapy****(380-386).
- There is currently no research that reports the effect of CBT on both cannabis use and somatoform disorders.
- Use of antidepressants may be required for comorbid depression and anxiety***(406, 407), with tricyclics being useful(377) in aiding chronic tension headaches and fibromyalgia.