Depression in primary hypothyroidism masquerading as inadequate or excessive L-thyroxine consumption

Depression may occasionally be a presenting feature of primary hypothyroidism but the influence of psychological illness upon L-thyroxine compliance in hypothyroidism has not been specifically addressed. We report six patients with primary hypothyroidism in whom repeated thyroid function tests implied that they were not taking their L-thyroxine as prescribed. The eventual recognition of underlying depression and its treatment led to appropriate treatment with thyroxine as evidenced by clinical euthyroidism and normal thyroid function tests.