Pharmacotherapy

For comorbid bipolar and AOD use disorders, multiple medications are often used to treat each specific disorder, such as the use of mood stabilisers (see Table 36), antipsychotics (see Table 33), and/or antidepressants (see Table 38) for the bipolar disorder, in conjunction with medication specifically to treat the AOD use disorder (e.g., naltrexone for alcohol use disorder) [540]. A recent update on the treatment of bipolar disorders recommended initiating pharmacological treatment with mood stabilisers and/or antipsychotics, and then later supplementing the treatment with antidepressant medication, due to the possibility of antidepressant-induced mania [564].

Adapted from Black Dog Institute [565]. For a full list of generic brands available, see the Therapeutic Goods Administration website (https://www.tga.gov.au/).

The effectiveness of mood stabilisers (e.g., lithium, sodium valproate, lamotrigine) in treating comorbid bipolar disorder and AOD use is yet to be fully established with only a small number of controlled trials in this area. An RCT examining the effectiveness of lithium in treating adolescents with bipolar disorder and AOD use disorders (primarily alcohol and/or cannabis) found that, relative to placebo, lithium had a positive effect on bipolar symptoms and on AOD use [566]. A further study demonstrated that lithium had an impact on reducing cannabis and cocaine use in people with comorbid bipolar disorder, but it is difficult to generalise the findings of this study due to less than one-quarter of the original sample completing the stabilisation phase and continuing into the main portion of the study [567].

Promising findings have also been found relating to the use of sodium valproate (or divalproex). In an uncontrolled study, Salloum and colleagues [568] found beneficial effects from divalproex alone in reducing bipolar symptoms and cocaine use. There is also some evidence to suggest that the addition of sodium valproate may further improve the effects of lithium [540]. In an RCT of people with bipolar disorder and alcohol use disorders, Salloum and colleagues [569] found that those randomised to receive lithium plus valproate had a greater reduction in heavy drinking days relative to those randomised to receive lithium alone. Manic and depressive symptoms improved equally in both groups. However, Kemp and colleagues [567] found no additional benefits for mood and AOD use when using divalproex and lithium, compared with lithium alone. As mentioned previously however, the findings of this study need to be interpreted with caution given the high drop-out rate.

Lamotrigine has been found to be associated with improvements in bipolar symptoms, craving, and AOD use in a number of open-label, uncontrolled trials [570, 571]. However, in a more recent RCT, the effects of lamotrigine on mood and cocaine use were not significantly different to placebo, although money spent on cocaine was reduced in the lamotrigine group [572].

A small number of uncontrolled, open-label trials have examined the use of the anti-psychotic quetiapine in the treatment of bipolar disorder comorbid with AOD use disorders. These studies have found that quetiapine has a positive impact on psychiatric symptoms, but no impact on AOD use [573, 574]. Furthermore, a large RCT examining the efficacy of quetiapine as an adjunct to lithium or divalproex among individuals with bipolar disorder and alcohol dependence found that there was no additional improvement in symptoms of mania or heavy drinking days, relative to a placebo control [575]. Lastly, it should be noted that the potential for the misuse of quetiapine, particularly in prison settings, has been well documented [576].

It is also important to bear in mind that clients with a comorbid bipolar disorder may be less likely to comply with medication if they enjoy their manic episodes. Measures to increase medication compliance may be particularly pertinent among this group (discussed later in this chapter). Other strategies to promote medication compliance among clients with comorbid bipolar disorder include the Improving Treatment Adherence Program, which is an adjunctive psychosocial approach designed to improve treatment adherence [577]. The Improving Treatment Adherence Program is delivered through individual sessions, a meeting with the client’s family member and/or significant other, and follow-up telephone contacts with the client and his/her significant other. Whilst an RCT testing this program is yet to establish the program’s efficacy, early results indicate that the intervention appears promising both in terms of feasibility and acceptability to clients, and also in terms of enhancing the benefits of existing treatments.