Geometry shader and triangle adjacency

I'm currently trying to change my project to use GL_TRIANGLE_ADJACENCY instead of GL_TRIANGLES.

Following this question, I have managed to construct my index buffer fine, but when it comes to the drawing stage, I'm getting unexpected results.

Here is my geometry shader code. Bare in mind that I store my indices like so:

(vertex1/adjacent1/vertex2/adjacent2/vertex3/adjacent3)

Geometry Shader

    #version 330

    precision highp float;

    layout (triangles_adjacency) in;
    layout (triangle_strip, max_vertices = 3) out;

    smooth in vec2 vVaryingTexCoords[];
    smooth in vec3 vVaryingNormals[];

    smooth out vec2 gsUV;
    smooth out vec3 gsNormals;

    void main(void)
    {
        int i;

        for(i = 0; i < gl_in.length(); i++)
        {
            switch(i)
            {
                case 0:
                case 2:
                case 4:
                    gl_Position = gl_in[i].gl_Position;
                    gsUV = vVaryingTexCoords[i];
                    gsNormals = vVaryingNormals[i];
                    EmitVertex();
                    break;

                default:
                    break;
            }
    }
    EndPrimitive();
}

Any ideas?

EDIT

Just like to point out that setting the adjacent index to be the same as the vertex index, i.e v1/v1/v2/v2/v3/v3 still produces the same results.