Anxiety associated with Parkinson’s disease can be caused by a number of different factors. If the anxiety occurs regularly, such as during an ‘off’ period (between or at the end of a dose of L-dopa), it may be a non-motor ‘off’ phenomenon. In such cases, the anxiety is best treated by stabilising the effect of the medication and the ‘off’ periods through various adjustments to the baseline dosage – ranging from higher doses, more frequent dosing, or the addition of various agents that can prolong and enhance the effect of the medication (for example, by adding MAO-B inhibitors, COMT inhibitors, or dopamine agonists) if the patient is not already taking any of these agents.
Sometimes, low blood pressure can manifest as anxiety, and usually as tiredness, though not always accompanied by dizziness or palpitations; in such cases, it is often related, for example, to standing up or having been standing for a while. Treatment involves maintaining a good fluid balance and controlling blood pressure.
If the anxiety is unrelated to L-dopa medication and other conditions, it may be linked to a lack of noradrenaline (and serotonin) without the patient simultaneously experiencing any low mood, in which case Venlafaxine may be a suitable option – but the indication must be assessed and carefully considered. If the medication is to be tried, doses range from 37.5 to 300 mg and must be monitored closely as treatment progresses. Treatment can be given in courses of 3–6 months or as a continuous, usually lower, dose over time.
/Håkan Widner