31 May 2005

Psychiatric co-morbidity in drug and alcohol dependence - with focus on anxiety symptoms

31st May 2005

Dr Glenys Dore, Psychiatrist and
Dr Lisa Juckes, Senior Registrar & Fellow in Psychiatry from Macquarie Hospital.

This session focused on anxiety disorders and their management, from both a pharmacological and non-pharmacological (eg: CBT) perspective. We were given a very complete hand-out which summarised, among other things, the diagnostic features of various anxiety disorders. These can also be accessed through the DSM-IV and good mental health texts.

Attention was drawn to the high rates of anxiety disorders in people with drug and alcohol dependence problem. The lifetime prevalence of anxiety disorders in the general population is between 10-20%, yet around 32% of people with an opiate use disorder will experience at least one of these disorders in their lifetime. The various anxiety disorders often co-exist both with substance misuse and other mental health disorders such as depression. A person may also have more than one anxiety disorder; the co-existence of panic disorder and agoraphobia being particularly common.

We were reminded that people with anxiety disorders, particularly generalised anxiety disorder (GAD), will often present with physical symptoms. Whilst there is a short list of medical conditions that it may be pertinent to screen for, these symptoms are usually the result of physiological arousal. There were a lot of questions about post-traumatic stress disorder (PTSD), and Dr Dore noted that opiate users score highly on both PTSD and depression scores. These two diagnoses can be difficult to sort out from each other when they co-exist and can be so intertwined that knowing what symptom belongs to which is impossible. However at the heart of PTSD is a life-threatening trauma to which the patient can usually direct us. We were reminded of the intense horror and fear felt by many victims of sexual assault, and how important the work of feminists has been in bringing this trauma under the PTSD umbrella of life-threatening events. Acute stress disorder was alluded to briefly, and can sometimes be a predecessor of PTSD, though it resolves in 60% of cases. On the other hand, some people may have no immediate anxiety following a life-threatening event, but over time begin to exhibit symptoms.

There was an interesting debate involving the audience about the extent to which D and A specialist doctors should manage the psychological issues. It was noted that some patients on methadone have a separate GP, and that in some cases it may be feasible for the drug and alcohol issues and psychological issues to be dealt with by two different doctors or other health professionals. However this was seen to be very situation specific, for example in rural areas the lack of availability of GPs can make separation of care impossible, and in other cases prescribers of methadone may find that they are in fact the only regular medical/counselling contact a patient attends.

Dr Dore pointed out that the "post-withdrawal syndrome" from alcohol can last 3 to 12 months, and that in that time there may be some unmasking of anxiety disorders which seem to apparently prolong this state. The link between excess alcohol consumption and anxiety was emphasised, and the difficulties of knowing whether excess anxiety causes excess drinking or vice versa was discussed. However the inability to be sure which is the chicken and which the egg should not prevent treatment. Dr Dore told us that the best management through this phase is CBT, and that medicating was not recommended unless the anxiety symptoms pre-dated the heavy drinking . and therefore appeared to indicate an independent anxiety disorder.

The post-withdrawal syndrome relating to opiates was also discussed and the importance of educating patients about this before they come off their opiates was emphasised. The first few months off opiates is often the time when psycho-social pressures build up strongly. There can be an expectation, either from the patient's community or even from the patient themselves, that mental health is linked wholly and solely to being opiate-free. Since factors influencing mental health are far more complex than that, it is crucial to support the patient through this ~6 month period. The major toxicological differences between alcohol and opiates was pointed out with reference to management in the post-withdrawal syndrome phase. Because of the direct toxic effects of alcohol on several organ systems, once the patient is over the acute withdrawal from alcohol they may start to feel better much sooner than the patient who has come off opiates. This in turn may have implications for the issue of medical management through the post-withdrawal syndrome phase.

The two main arms of treatment for both anxiety disorders and post-withdrawal syndromes are CBT and pharmacological. Cognitive behavioural therapy starts with the provision of information to the patient about the nature of their condition; how and why it occurs and what can be done about it. There is an emphasis on promoting active participation from the patient. The principles of CBT apply to all anxiety disorders, so that whilst management is fine-tuned to suit the patient overall strategies and aims are similar.

Patients can be encouraged to self-monitor their treatment by keeping diaries, noting what works and when. Structured problem solving can be taught, and slow breathing (the "six-second cycle") is a very useful technique to teach the patient. Relaxation therapies such as muscle relaxation or meditation can be taught. Assertiveness and social skills training is also part of CBT. Other important CBT strategies include graded exposure to the feared situations and cognitive challenge work.

Dr Dore noted that most of the anti-depressants are also excellent anti-anxiety agents. Her handout gave details of the various groups of anti-depressants that are useful. Special attention was paid to SSRIs, and Dr Dore reminded us of the interaction between fluvoxamine and methadone. This particular SSRI, when used with methadone, can cause methadone toxicity by elevating methadone blood levels and is thus best avoided. Dr Dore also noted that it is wise to commence the SSRI's at a very low dose in anxiety states (eg 25mg sertraline) as the SSRIs can cause an initial increase in anxiety which can be prevented with a "start low" approach. While venlafaxine is useful for anxiety disorders, it can be problematic when patients stop it abruptly because of unpleasant rebound symptoms including increased anxiety. It was noted that patients on methadone maintenance therapy may be more likely to "stop/start" anti-anxiety medication, which adds weight to Dr Dore's advice.

Special mention was made of the RIMAs (such as moclobemide) and their excellent anti-anxiety properties. Tri-cyclics tend to be avoided these days due to their side effect profile and toxicity in overdose. Mirtazapine was also noted to be effective in this group of patients, though weight gain can be a major problem. Interestingly, mirtazapine has a greater sedative effect at a dose of 15mg compared to 30mg. Reboxetine ('Edronax', an SNRI) needs to be carefully titrated against the patient's response: Dr Dore mentioned that she starts very low and usually "trickles in" 2mg every few days. Reboxetine can be effective in increasing patients' motivation, but this effect can trip over into agitation if not monitored carefully.

The atypical anti-psychotics can be used as second-line medication for anxiety disorders, but in much lower doses than are used for treatment of psychoses eg sometimes 25 - 50mg of quetiapine (Seroquel) is a large enough dose to maintain an anti-anxiety effect, while other patients may need 100 - 200 mg. Anti-convulsants were also briefly mentioned as possibilities if anxiety is refractory to other treatments. Sodium valproate (Epilim) is best avoided in women of child-bearing age due to its deleterious effects on the foetus. Complex anxiety states requiring more complex medication regimes are best managed in partnership with a psychiatrist. Also, PBS rules must be carefully observed as not all of these drugs are covered for general use.

Finally, Dr Dore told us that benzodiazepines are best avoided in patients with a history of substance abuse, though she outlined some exceptions to this. The beginnings of a lively debate about the role of benzodiazepines came from the audience, and we look forward to a future seminar on this important and complex topic.

Written by Dr Jenny James, Daruk Aboriginal Medical Service.