The Effect of Behavioral Intervention on the Cannabinoid Receptor System in Patients With Bipolar Affective Disorder

Bipolar affective disorder (BAD) is often poorly controlled by prescribed drugs. Clinical observations suggest that the endocannabinoid system is dysfunctional in BAD and fails to control the level of cortical excitation and inhibition in the brain. Thus, excessively high endocannabinoid tone (mania) or excessively low endocannabinoid tone (depression) may manifest itself in BAD patients. Interestingly, cannabis use is common in patients with this disorder and anecdotal reports suggest that some patients take it to alleviate symptoms of both mania and depression. The investigators have recently studied brain activations during a cold stress paradigm in a 57 year old Dutch national (Wim Hof), the so-called "Iceman", who has the ability to withstand frequent prolonged periods of extreme cold exposure using a self-developed technique that includes a combination of breathing exercises, cold exposure and meditation (referred to as the WH technique). The WH technique allows the "Iceman" to regulate his own autonomic nervous system in the presence of severe cold and to perform remarkable acts of survival under extreme thermal conditions. Moreover, it has been shown that the WH technique can be successfully taught to novice users. Preliminary studies performed by the investigators have examined CNS mechanisms associated with the practice of the WH technique and the obtained findings unequivocally demonstrated activation of autonomic brainstem areas that are implicated in stress-induced analgesia as well as cognitive cortical areas that are associated with self-reflection (such as the anterior insula). In particular, a strong activation of the periaqueductal gray (PAG) was determined, which is implicated in the release of endogenous opiates/cannabinoids that mediate decreased sensitivity to cold exposure and (via connections to higher-order cortical areas) promote a feeling of euphoria and well-being. This finding suggests that the WH technique might allow practitioners to assert increased level of control over key components of the affective system and as a result might be a viable, non-drug related approach for patients with pathological mood swings. The investigators believe that this method might be particularly effective in patients suffering from BAD, as the practice of the WH technique can be implemented during both remission and at the onset of highly motivational manic episodes, which will then help to limit the effects of negative mood swings during depressive (and manic) episodes. The investigators will study the effects of the WH technique on cannabinoid receptor density using the cannabinoid PET tracer (F18-FMPEP-d2) by determining regional changes in cannabinoid receptor density in various brain regions prior and post behavioral intervention.